* [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support
@ 2012-08-21 13:51 Bharat Bhushan
2012-08-21 13:51 ` [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct Bharat Bhushan
` (5 more replies)
0 siblings, 6 replies; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:51 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
From: Bharat Bhushan <bharat.bhushan@freescale.com>
This patchset adds the QEMU debug stub support for powerpc (booke/bookehv).
[1/6] KVM: PPC: booke: use vcpu reference from thread_struct
- This is a cleanup patch to use vcpu reference from thread struct
[2/6] KVM: PPC: booke: Allow multiple exception types
[3/6] KVM: PPC: booke: Added debug handler
- These two patches install the KVM debug handler.
[4/6] KVM: PPC: debug stub interface parameter defined
[5/6] booke: Added DBCR4 SPR number
[6/6] KVM: booke/bookehv: Add debug stub support
- Add the debug stub interface on booke/bookehv
Bharat Bhushan (6):
KVM: PPC: booke: use vcpu reference from thread_struct
KVM: PPC: booke: Allow multiple exception types
KVM: PPC: booke: Added debug handler
KVM: PPC: debug stub interface parameter defined
booke: Added DBCR4 SPR number
KVM: booke/bookehv: Add debug stub support
arch/powerpc/include/asm/kvm.h | 54 +++++++++
arch/powerpc/include/asm/kvm_host.h | 6 +
arch/powerpc/include/asm/kvm_ppc.h | 2 -
arch/powerpc/include/asm/reg_booke.h | 1 +
arch/powerpc/kernel/asm-offsets.c | 29 +++++-
arch/powerpc/kvm/book3s.c | 6 +
arch/powerpc/kvm/booke.c | 162 ++++++++++++++++++++++++---
arch/powerpc/kvm/booke.h | 1 +
arch/powerpc/kvm/booke_interrupts.S | 198 +++++++++++++++++++++++++++++++--
arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++-
arch/powerpc/kvm/e500.c | 16 ++-
arch/powerpc/kvm/e500mc.c | 3 +-
arch/powerpc/kvm/powerpc.c | 6 -
13 files changed, 575 insertions(+), 50 deletions(-)
^ permalink raw reply [flat|nested] 32+ messages in thread
* [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
@ 2012-08-21 13:51 ` Bharat Bhushan
2012-09-24 16:27 ` Alexander Graf
2012-08-21 13:51 ` [PATCH 2/6] KVM: PPC: booke: Allow multiple exception types Bharat Bhushan
` (4 subsequent siblings)
5 siblings, 1 reply; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:51 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
Like other places, use thread_struct to get vcpu reference.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
arch/powerpc/kernel/asm-offsets.c | 2 +-
arch/powerpc/kvm/booke_interrupts.S | 6 ++----
2 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 85b05c4..fbb999c 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -116,7 +116,7 @@ int main(void)
#ifdef CONFIG_KVM_BOOK3S_32_HANDLER
DEFINE(THREAD_KVM_SVCPU, offsetof(struct thread_struct, kvm_shadow_vcpu));
#endif
-#ifdef CONFIG_KVM_BOOKE_HV
+#if defined(CONFIG_KVM) && defined(CONFIG_BOOKE)
DEFINE(THREAD_KVM_VCPU, offsetof(struct thread_struct, kvm_vcpu));
#endif
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index bb46b32..ca16d57 100644
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -56,7 +56,8 @@
_GLOBAL(kvmppc_handler_\ivor_nr)
/* Get pointer to vcpu and record exit number. */
mtspr \scratch , r4
- mfspr r4, SPRN_SPRG_RVCPU
+ mfspr r4, SPRN_SPRG_THREAD
+ lwz r4, THREAD_KVM_VCPU(r4)
stw r3, VCPU_GPR(R3)(r4)
stw r5, VCPU_GPR(R5)(r4)
stw r6, VCPU_GPR(R6)(r4)
@@ -402,9 +403,6 @@ lightweight_exit:
lwz r8, kvmppc_booke_handlers@l(r8)
mtspr SPRN_IVPR, r8
- /* Save vcpu pointer for the exception handlers. */
- mtspr SPRN_SPRG_WVCPU, r4
-
lwz r5, VCPU_SHARED(r4)
/* Can't switch the stack pointer until after IVPR is switched,
--
1.7.0.4
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH 2/6] KVM: PPC: booke: Allow multiple exception types
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
2012-08-21 13:51 ` [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct Bharat Bhushan
@ 2012-08-21 13:51 ` Bharat Bhushan
2012-08-21 13:51 ` [PATCH 3/6] KVM: PPC: booke: Added debug handler Bharat Bhushan
` (3 subsequent siblings)
5 siblings, 0 replies; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:51 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
Current kvmppc_booke_handlers uses the same macro (KVM_HANDLER) and
all handlers are considered to be the same size. This will not be
the case if we want to use different macros for different handlers.
This patch improves the kvmppc_booke_handler so that it can
support different macros for different handlers.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
[bharat.bhushan@freescale.com: Substantial changes]
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
arch/powerpc/include/asm/kvm_ppc.h | 2 -
arch/powerpc/kvm/booke.c | 14 ++++++++----
arch/powerpc/kvm/booke.h | 1 +
arch/powerpc/kvm/booke_interrupts.S | 37 ++++++++++++++++++++++++++++++++--
arch/powerpc/kvm/e500.c | 16 +++++++++-----
5 files changed, 54 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index c06a64b..ba60230 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -47,8 +47,6 @@ enum emulation_result {
extern int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu);
extern int __kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu);
-extern char kvmppc_handlers_start[];
-extern unsigned long kvmppc_handler_len;
extern void kvmppc_handler_highmem(void);
extern void kvmppc_dump_vcpu(struct kvm_vcpu *vcpu);
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 959aae9..90d4798 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1493,7 +1493,9 @@ int __init kvmppc_booke_init(void)
{
#ifndef CONFIG_KVM_BOOKE_HV
unsigned long ivor[16];
+ unsigned long *handler = kvmppc_booke_handler_addr;
unsigned long max_ivor = 0;
+ unsigned long handler_len;
int i;
/* We install our own exception handlers by hijacking IVPR. IVPR must
@@ -1526,14 +1528,16 @@ int __init kvmppc_booke_init(void)
for (i = 0; i < 16; i++) {
if (ivor[i] > max_ivor)
- max_ivor = ivor[i];
+ max_ivor = i;
+ handler_len = handler[i + 1] - handler[i];
memcpy((void *)kvmppc_booke_handlers + ivor[i],
- kvmppc_handlers_start + i * kvmppc_handler_len,
- kvmppc_handler_len);
+ (void *)handler[i], handler_len);
}
- flush_icache_range(kvmppc_booke_handlers,
- kvmppc_booke_handlers + max_ivor + kvmppc_handler_len);
+
+ handler_len = handler[max_ivor + 1] - handler[max_ivor];
+ flush_icache_range(kvmppc_booke_handlers, kvmppc_booke_handlers +
+ ivor[max_ivor] + handler_len);
#endif /* !BOOKE_HV */
return 0;
}
diff --git a/arch/powerpc/kvm/booke.h b/arch/powerpc/kvm/booke.h
index ba61974..de9e526 100644
--- a/arch/powerpc/kvm/booke.h
+++ b/arch/powerpc/kvm/booke.h
@@ -65,6 +65,7 @@
(1 << BOOKE_IRQPRIO_CRITICAL))
extern unsigned long kvmppc_booke_handlers;
+extern unsigned long kvmppc_booke_handler_addr[];
void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr);
void kvmppc_mmu_msr_notify(struct kvm_vcpu *vcpu, u32 old_msr);
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index ca16d57..eae8483 100644
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -74,6 +74,14 @@ _GLOBAL(kvmppc_handler_\ivor_nr)
bctr
.endm
+.macro KVM_HANDLER_ADDR ivor_nr
+ .long kvmppc_handler_\ivor_nr
+.endm
+
+.macro KVM_HANDLER_END
+ .long kvmppc_handlers_end
+.endm
+
_GLOBAL(kvmppc_handlers_start)
KVM_HANDLER BOOKE_INTERRUPT_CRITICAL SPRN_SPRG_RSCRATCH_CRIT SPRN_CSRR0
KVM_HANDLER BOOKE_INTERRUPT_MACHINE_CHECK SPRN_SPRG_RSCRATCH_MC SPRN_MCSRR0
@@ -94,9 +102,7 @@ KVM_HANDLER BOOKE_INTERRUPT_DEBUG SPRN_SPRG_RSCRATCH_CRIT SPRN_CSRR0
KVM_HANDLER BOOKE_INTERRUPT_SPE_UNAVAIL SPRN_SPRG_RSCRATCH0 SPRN_SRR0
KVM_HANDLER BOOKE_INTERRUPT_SPE_FP_DATA SPRN_SPRG_RSCRATCH0 SPRN_SRR0
KVM_HANDLER BOOKE_INTERRUPT_SPE_FP_ROUND SPRN_SPRG_RSCRATCH0 SPRN_SRR0
-
-_GLOBAL(kvmppc_handler_len)
- .long kvmppc_handler_1 - kvmppc_handler_0
+_GLOBAL(kvmppc_handlers_end)
/* Registers:
* SPRG_SCRATCH0: guest r4
@@ -461,6 +467,31 @@ lightweight_exit:
lwz r4, VCPU_GPR(R4)(r4)
rfi
+ .data
+ .align 4
+ .globl kvmppc_booke_handler_addr
+kvmppc_booke_handler_addr:
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_CRITICAL
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_MACHINE_CHECK
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_DATA_STORAGE
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_INST_STORAGE
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_EXTERNAL
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_ALIGNMENT
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_PROGRAM
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_FP_UNAVAIL
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_SYSCALL
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_AP_UNAVAIL
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_DECREMENTER
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_FIT
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_WATCHDOG
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_DTLB_MISS
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_ITLB_MISS
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_DEBUG
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_SPE_UNAVAIL
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_SPE_FP_DATA
+KVM_HANDLER_ADDR BOOKE_INTERRUPT_SPE_FP_ROUND
+KVM_HANDLER_END /*Always keep this in end*/
+
#ifdef CONFIG_SPE
_GLOBAL(kvmppc_save_guest_spe)
cmpi 0,r3,0
diff --git a/arch/powerpc/kvm/e500.c b/arch/powerpc/kvm/e500.c
index b479ed7..6dd4de7 100644
--- a/arch/powerpc/kvm/e500.c
+++ b/arch/powerpc/kvm/e500.c
@@ -491,6 +491,9 @@ static int __init kvmppc_e500_init(void)
{
int r, i;
unsigned long ivor[3];
+ /* Process remaining handlers above the generic first 16 */
+ unsigned long *handler = &kvmppc_booke_handler_addr[16];
+ unsigned long handler_len;
unsigned long max_ivor = 0;
r = kvmppc_core_check_processor_compat();
@@ -506,15 +509,16 @@ static int __init kvmppc_e500_init(void)
ivor[1] = mfspr(SPRN_IVOR33);
ivor[2] = mfspr(SPRN_IVOR34);
for (i = 0; i < 3; i++) {
- if (ivor[i] > max_ivor)
- max_ivor = ivor[i];
+ if (ivor[i] > ivor[max_ivor])
+ max_ivor = i;
+ handler_len = handler[i + 1] - handler[i];
memcpy((void *)kvmppc_booke_handlers + ivor[i],
- kvmppc_handlers_start + (i + 16) * kvmppc_handler_len,
- kvmppc_handler_len);
+ (void *)handler[i], handler_len);
}
- flush_icache_range(kvmppc_booke_handlers,
- kvmppc_booke_handlers + max_ivor + kvmppc_handler_len);
+ handler_len = handler[max_ivor + 1] - handler[max_ivor];
+ flush_icache_range(kvmppc_booke_handlers, kvmppc_booke_handlers +
+ ivor[max_ivor] + handler_len);
return kvm_init(NULL, sizeof(struct kvmppc_vcpu_e500), 0, THIS_MODULE);
}
--
1.7.0.4
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH 3/6] KVM: PPC: booke: Added debug handler
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
2012-08-21 13:51 ` [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct Bharat Bhushan
2012-08-21 13:51 ` [PATCH 2/6] KVM: PPC: booke: Allow multiple exception types Bharat Bhushan
@ 2012-08-21 13:51 ` Bharat Bhushan
2012-08-21 13:51 ` [PATCH 4/6] KVM: PPC: debug stub interface parameter defined Bharat Bhushan
` (2 subsequent siblings)
5 siblings, 0 replies; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:51 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
Installed debug handler will be used for guest debug support
and debug facility emulation features (patches for these
features will follow this patch).
Signed-off-by: Liu Yu <yu.liu@freescale.com>
[bharat.bhushan@freescale.com: Substantial changes]
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
arch/powerpc/include/asm/kvm_host.h | 1 +
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kvm/booke_interrupts.S | 49 ++++++++++++++++++++++++++++++-----
3 files changed, 44 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index f20a5ef..c7219c1 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -495,6 +495,7 @@ struct kvm_vcpu_arch {
u32 tlbcfg[4];
u32 mmucfg;
u32 epr;
+ u32 crit_save;
struct kvmppc_booke_debug_reg dbg_reg;
#endif
gpa_t paddr_accessed;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index fbb999c..555448e 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -563,6 +563,7 @@ int main(void)
DEFINE(VCPU_LAST_INST, offsetof(struct kvm_vcpu, arch.last_inst));
DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
+ DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
#endif /* CONFIG_PPC_BOOK3S */
#endif /* CONFIG_KVM */
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index eae8483..dd9c5d4 100644
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -52,12 +52,7 @@
(1<<BOOKE_INTERRUPT_PROGRAM) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
-.macro KVM_HANDLER ivor_nr scratch srr0
-_GLOBAL(kvmppc_handler_\ivor_nr)
- /* Get pointer to vcpu and record exit number. */
- mtspr \scratch , r4
- mfspr r4, SPRN_SPRG_THREAD
- lwz r4, THREAD_KVM_VCPU(r4)
+.macro __KVM_HANDLER ivor_nr scratch srr0
stw r3, VCPU_GPR(R3)(r4)
stw r5, VCPU_GPR(R5)(r4)
stw r6, VCPU_GPR(R6)(r4)
@@ -74,6 +69,46 @@ _GLOBAL(kvmppc_handler_\ivor_nr)
bctr
.endm
+.macro KVM_HANDLER ivor_nr scratch srr0
+_GLOBAL(kvmppc_handler_\ivor_nr)
+ /* Get pointer to vcpu and record exit number. */
+ mtspr \scratch , r4
+ mfspr r4, SPRN_SPRG_THREAD
+ lwz r4, THREAD_KVM_VCPU(r4)
+ __KVM_HANDLER \ivor_nr \scratch \srr0
+.endm
+
+.macro KVM_DBG_HANDLER ivor_nr scratch srr0
+_GLOBAL(kvmppc_handler_\ivor_nr)
+ mtspr \scratch, r4
+ mfspr r4, SPRN_SPRG_THREAD
+ lwz r4, THREAD_KVM_VCPU(r4)
+ stw r3, VCPU_CRIT_SAVE(r4)
+ mfcr r3
+ mfspr r4, SPRN_CSRR1
+ andi. r4, r4, MSR_PR
+ bne 1f
+ /* debug interrupt happened in enter/exit path */
+ mfspr r4, SPRN_CSRR1
+ rlwinm r4, r4, 0, ~MSR_DE
+ mtspr SPRN_CSRR1, r4
+ lis r4, 0xffff
+ ori r4, r4, 0xffff
+ mtspr SPRN_DBSR, r4
+ mfspr r4, SPRN_SPRG_THREAD
+ lwz r4, THREAD_KVM_VCPU(r4)
+ mtcr r3
+ lwz r3, VCPU_CRIT_SAVE(r4)
+ mfspr r4, \scratch
+ rfci
+1: /* debug interrupt happened in guest */
+ mtcr r3
+ mfspr r4, SPRN_SPRG_THREAD
+ lwz r4, THREAD_KVM_VCPU(r4)
+ lwz r3, VCPU_CRIT_SAVE(r4)
+ __KVM_HANDLER \ivor_nr \scratch \srr0
+.endm
+
.macro KVM_HANDLER_ADDR ivor_nr
.long kvmppc_handler_\ivor_nr
.endm
@@ -98,7 +133,7 @@ KVM_HANDLER BOOKE_INTERRUPT_FIT SPRN_SPRG_RSCRATCH0 SPRN_SRR0
KVM_HANDLER BOOKE_INTERRUPT_WATCHDOG SPRN_SPRG_RSCRATCH_CRIT SPRN_CSRR0
KVM_HANDLER BOOKE_INTERRUPT_DTLB_MISS SPRN_SPRG_RSCRATCH0 SPRN_SRR0
KVM_HANDLER BOOKE_INTERRUPT_ITLB_MISS SPRN_SPRG_RSCRATCH0 SPRN_SRR0
-KVM_HANDLER BOOKE_INTERRUPT_DEBUG SPRN_SPRG_RSCRATCH_CRIT SPRN_CSRR0
+KVM_DBG_HANDLER BOOKE_INTERRUPT_DEBUG SPRN_SPRG_RSCRATCH_CRIT SPRN_CSRR0
KVM_HANDLER BOOKE_INTERRUPT_SPE_UNAVAIL SPRN_SPRG_RSCRATCH0 SPRN_SRR0
KVM_HANDLER BOOKE_INTERRUPT_SPE_FP_DATA SPRN_SPRG_RSCRATCH0 SPRN_SRR0
KVM_HANDLER BOOKE_INTERRUPT_SPE_FP_ROUND SPRN_SPRG_RSCRATCH0 SPRN_SRR0
--
1.7.0.4
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
` (2 preceding siblings ...)
2012-08-21 13:51 ` [PATCH 3/6] KVM: PPC: booke: Added debug handler Bharat Bhushan
@ 2012-08-21 13:51 ` Bharat Bhushan
2012-09-24 15:38 ` Alexander Graf
2012-08-21 13:51 ` [PATCH 5/6] booke: Added DBCR4 SPR number Bharat Bhushan
2012-08-21 13:52 ` [PATCH 6/6] KVM: booke/bookehv: Add debug stub support Bharat Bhushan
5 siblings, 1 reply; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:51 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
This patch defines the interface parameter for KVM_SET_GUEST_DEBUG
ioctl support. Follow up patches will use this for setting up
hardware breakpoints, watchpoints and software breakpoints.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
arch/powerpc/include/asm/kvm.h | 33 +++++++++++++++++++++++++++++++++
arch/powerpc/kvm/book3s.c | 6 ++++++
arch/powerpc/kvm/booke.c | 6 ++++++
arch/powerpc/kvm/powerpc.c | 6 ------
4 files changed, 45 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
index 3c14202..61b197e 100644
--- a/arch/powerpc/include/asm/kvm.h
+++ b/arch/powerpc/include/asm/kvm.h
@@ -269,8 +269,41 @@ struct kvm_debug_exit_arch {
/* for KVM_SET_GUEST_DEBUG */
struct kvm_guest_debug_arch {
+ struct {
+ /* H/W breakpoint/watchpoint address */
+ __u64 addr;
+ /*
+ * Type denotes h/w breakpoint, read watchpoint, write
+ * watchpoint or watchpoint (both read and write).
+ */
+#define KVMPPC_DEBUG_NOTYPE 0x0
+#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
+#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
+#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
+ __u32 type;
+ __u32 pad1;
+ __u64 pad2;
+ } bp[16];
};
+/* Debug related defines */
+/*
+ * kvm_guest_debug->control is a 32 bit field. The lower 16 bits are generic
+ * and upper 16 bits are architecture specific. Architecture specific defines
+ * that ioctl is for setting hardware breakpoint or software breakpoint.
+ */
+#define KVM_GUESTDBG_USE_SW_BP 0x00010000
+#define KVM_GUESTDBG_USE_HW_BP 0x00020000
+
+/* When setting software breakpoint, Change the software breakpoint
+ * instruction to special trap instruction and set KVM_GUESTDBG_USE_SW_BP
+ * flag in kvm_guest_debug->control. KVM does keep track of software
+ * breakpoints. So when KVM_GUESTDBG_USE_SW_BP flag is set and special trap
+ * instruction is executed by guest then exit to userspace.
+ * NOTE: A Nice interface can be added to get the special trap instruction.
+ */
+#define KVMPPC_INST_GUEST_GDB 0x7C00021C /* ehpriv OC=0 */
+
/* definition of registers in kvm_run */
struct kvm_sync_regs {
};
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index e946665..385b027 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -475,6 +475,12 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
return 0;
}
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
+{
+ return -EINVAL;
+}
+
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
return -ENOTSUPP;
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 90d4798..dd0e5b8 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1403,6 +1403,12 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
return r;
}
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
+{
+ return -EINVAL;
+}
+
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
return -ENOTSUPP;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 32d217c..c565f5d 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -518,12 +518,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
vcpu->cpu = -1;
}
-int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
- struct kvm_guest_debug *dbg)
-{
- return -EINVAL;
-}
-
static void kvmppc_complete_dcr_load(struct kvm_vcpu *vcpu,
struct kvm_run *run)
{
--
1.7.0.4
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH 5/6] booke: Added DBCR4 SPR number
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
` (3 preceding siblings ...)
2012-08-21 13:51 ` [PATCH 4/6] KVM: PPC: debug stub interface parameter defined Bharat Bhushan
@ 2012-08-21 13:51 ` Bharat Bhushan
2012-09-05 23:24 ` Scott Wood
2012-08-21 13:52 ` [PATCH 6/6] KVM: booke/bookehv: Add debug stub support Bharat Bhushan
5 siblings, 1 reply; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:51 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
arch/powerpc/include/asm/reg_booke.h | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/reg_booke.h b/arch/powerpc/include/asm/reg_booke.h
index e07e6af..b417de3 100644
--- a/arch/powerpc/include/asm/reg_booke.h
+++ b/arch/powerpc/include/asm/reg_booke.h
@@ -56,6 +56,7 @@
#define SPRN_SPRG7W 0x117 /* Special Purpose Register General 7 Write */
#define SPRN_EPCR 0x133 /* Embedded Processor Control Register */
#define SPRN_DBCR2 0x136 /* Debug Control Register 2 */
+#define SPRN_DBCR4 0x233 /* Debug Control Register 4 */
#define SPRN_MSRP 0x137 /* MSR Protect Register */
#define SPRN_IAC3 0x13A /* Instruction Address Compare 3 */
#define SPRN_IAC4 0x13B /* Instruction Address Compare 4 */
--
1.7.0.4
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
` (4 preceding siblings ...)
2012-08-21 13:51 ` [PATCH 5/6] booke: Added DBCR4 SPR number Bharat Bhushan
@ 2012-08-21 13:52 ` Bharat Bhushan
2012-09-05 23:23 ` Scott Wood
2012-09-24 16:20 ` Alexander Graf
5 siblings, 2 replies; 32+ messages in thread
From: Bharat Bhushan @ 2012-08-21 13:52 UTC (permalink / raw)
To: kvm-ppc, kvm, agraf; +Cc: Bharat Bhushan
This patch adds the debug stub support on booke/bookehv.
Now QEMU debug stub can use hw breakpoint, watchpoint and
software breakpoint to debug guest.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
arch/powerpc/include/asm/kvm.h | 29 ++++++-
arch/powerpc/include/asm/kvm_host.h | 5 +
arch/powerpc/kernel/asm-offsets.c | 26 ++++++
arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++----
arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++++++++++-
arch/powerpc/kvm/e500mc.c | 3 +-
7 files changed, 435 insertions(+), 23 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
index 61b197e..53479ea 100644
--- a/arch/powerpc/include/asm/kvm.h
+++ b/arch/powerpc/include/asm/kvm.h
@@ -25,6 +25,7 @@
/* Select powerpc specific features in <linux/kvm.h> */
#define __KVM_HAVE_SPAPR_TCE
#define __KVM_HAVE_PPC_SMT
+#define __KVM_HAVE_GUEST_DEBUG
struct kvm_regs {
__u64 pc;
@@ -264,7 +265,31 @@ struct kvm_fpu {
__u64 fpr[32];
};
+
+/*
+ * Defines for h/w breakpoint, watchpoint (read, write or both) and
+ * software breakpoint.
+ * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
+ * for KVM_DEBUG_EXIT.
+ */
+#define KVMPPC_DEBUG_NONE 0x0
+#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
+#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
+#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
struct kvm_debug_exit_arch {
+ __u64 pc;
+ /*
+ * exception -> returns the exception number. If the KVM_DEBUG_EXIT
+ * exit is not handled (say not h/w breakpoint or software breakpoint
+ * set for this address) by qemu then it is supposed to inject this
+ * exception to guest.
+ */
+ __u32 exception;
+ /*
+ * exiting to userspace because of h/w breakpoint, watchpoint
+ * (read, write or both) and software breakpoint.
+ */
+ __u32 status;
};
/* for KVM_SET_GUEST_DEBUG */
@@ -276,10 +301,6 @@ struct kvm_guest_debug_arch {
* Type denotes h/w breakpoint, read watchpoint, write
* watchpoint or watchpoint (both read and write).
*/
-#define KVMPPC_DEBUG_NOTYPE 0x0
-#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
-#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
-#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
__u32 type;
__u32 pad1;
__u64 pad2;
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index c7219c1..3ba465a 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -496,7 +496,12 @@ struct kvm_vcpu_arch {
u32 mmucfg;
u32 epr;
u32 crit_save;
+ /* guest debug registers*/
struct kvmppc_booke_debug_reg dbg_reg;
+ /* shadow debug registers */
+ struct kvmppc_booke_debug_reg shadow_dbg_reg;
+ /* host debug registers*/
+ struct kvmppc_booke_debug_reg host_dbg_reg;
#endif
gpa_t paddr_accessed;
gva_t vaddr_accessed;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 555448e..6987821 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -564,6 +564,32 @@ int main(void)
DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
+ DEFINE(VCPU_DBSR, offsetof(struct kvm_vcpu, arch.dbsr));
+ DEFINE(VCPU_SHADOW_DBG, offsetof(struct kvm_vcpu, arch.shadow_dbg_reg));
+ DEFINE(VCPU_HOST_DBG, offsetof(struct kvm_vcpu, arch.host_dbg_reg));
+ DEFINE(KVMPPC_DBG_DBCR0, offsetof(struct kvmppc_booke_debug_reg,
+ dbcr0));
+ DEFINE(KVMPPC_DBG_DBCR1, offsetof(struct kvmppc_booke_debug_reg,
+ dbcr1));
+ DEFINE(KVMPPC_DBG_DBCR2, offsetof(struct kvmppc_booke_debug_reg,
+ dbcr2));
+#ifdef CONFIG_KVM_E500MC
+ DEFINE(KVMPPC_DBG_DBCR4, offsetof(struct kvmppc_booke_debug_reg,
+ dbcr4));
+#endif
+ DEFINE(KVMPPC_DBG_IAC1, offsetof(struct kvmppc_booke_debug_reg,
+ iac[0]));
+ DEFINE(KVMPPC_DBG_IAC2, offsetof(struct kvmppc_booke_debug_reg,
+ iac[1]));
+ DEFINE(KVMPPC_DBG_IAC3, offsetof(struct kvmppc_booke_debug_reg,
+ iac[2]));
+ DEFINE(KVMPPC_DBG_IAC4, offsetof(struct kvmppc_booke_debug_reg,
+ iac[3]));
+ DEFINE(KVMPPC_DBG_DAC1, offsetof(struct kvmppc_booke_debug_reg,
+ dac[0]));
+ DEFINE(KVMPPC_DBG_DAC2, offsetof(struct kvmppc_booke_debug_reg,
+ dac[1]));
+ DEFINE(VCPU_GUEST_DEBUG, offsetof(struct kvm_vcpu, guest_debug));
#endif /* CONFIG_PPC_BOOK3S */
#endif /* CONFIG_KVM */
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index dd0e5b8..4d82e34 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -132,6 +132,9 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)
#ifdef CONFIG_KVM_BOOKE_HV
new_msr |= MSR_GS;
+
+ if (vcpu->guest_debug)
+ new_msr |= MSR_DE;
#endif
vcpu->arch.shared->msr = new_msr;
@@ -667,10 +670,21 @@ out:
return ret;
}
-static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
+static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
+ int exit_nr)
{
enum emulation_result er;
+ if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
+ vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
+ run->exit_reason = KVM_EXIT_DEBUG;
+ run->debug.arch.pc = vcpu->arch.pc;
+ run->debug.arch.exception = exit_nr;
+ run->debug.arch.status = 0;
+ kvmppc_account_exit(vcpu, DEBUG_EXITS);
+ return RESUME_HOST;
+ }
+
er = kvmppc_emulate_instruction(run, vcpu);
switch (er) {
case EMULATE_DONE:
@@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
default:
BUG();
}
+
+ if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
+ (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
+ run->exit_reason = KVM_EXIT_DEBUG;
+ return RESUME_HOST;
+ }
+}
+
+static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+ u32 dbsr;
+
+#ifndef CONFIG_KVM_BOOKE_HV
+ if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
+ vcpu->arch.pc = mfspr(SPRN_DSRR0);
+ else
+ vcpu->arch.pc = mfspr(SPRN_CSRR0);
+#endif
+ dbsr = vcpu->arch.dbsr;
+
+ run->debug.arch.pc = vcpu->arch.pc;
+ run->debug.arch.status = 0;
+ vcpu->arch.dbsr = 0;
+
+ if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
+ run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
+ } else {
+ if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
+ run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
+ else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
+ run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
+ if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
+ run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
+ else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
+ run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
+ }
+
+ return RESUME_HOST;
}
static void kvmppc_fill_pt_regs(struct pt_regs *regs)
@@ -843,7 +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
break;
case BOOKE_INTERRUPT_HV_PRIV:
- r = emulation_exit(run, vcpu);
+ r = emulation_exit(run, vcpu, exit_nr);
break;
case BOOKE_INTERRUPT_PROGRAM:
@@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
break;
}
- r = emulation_exit(run, vcpu);
+ r = emulation_exit(run, vcpu, exit_nr);
break;
case BOOKE_INTERRUPT_FP_UNAVAIL:
@@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
}
case BOOKE_INTERRUPT_DEBUG: {
- u32 dbsr;
-
- vcpu->arch.pc = mfspr(SPRN_CSRR0);
-
- /* clear IAC events in DBSR register */
- dbsr = mfspr(SPRN_DBSR);
- dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
- mtspr(SPRN_DBSR, dbsr);
-
- run->exit_reason = KVM_EXIT_DEBUG;
+ r = kvmppc_handle_debug(run, vcpu);
+ if (r == RESUME_HOST) {
+ run->debug.arch.exception = exit_nr;
+ run->exit_reason = KVM_EXIT_DEBUG;
+ }
kvmppc_account_exit(vcpu, DEBUG_EXITS);
- r = RESUME_HOST;
break;
}
@@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
return r;
}
+#define BP_NUM KVMPPC_BOOKE_IAC_NUM
+#define WP_NUM KVMPPC_BOOKE_DAC_NUM
+
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
struct kvm_guest_debug *dbg)
{
- return -EINVAL;
+
+ if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
+ /* Clear All debug events */
+ vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
+ vcpu->guest_debug = 0;
+ return 0;
+ }
+
+ vcpu->guest_debug = dbg->control;
+ vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
+
+ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+ vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
+
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
+ struct kvmppc_booke_debug_reg *gdbgr =
+ &(vcpu->arch.shadow_dbg_reg);
+ int n, b = 0, w = 0;
+ const u32 bp_code[] = {
+ DBCR0_IAC1 | DBCR0_IDM,
+ DBCR0_IAC2 | DBCR0_IDM,
+ DBCR0_IAC3 | DBCR0_IDM,
+ DBCR0_IAC4 | DBCR0_IDM
+ };
+ const u32 wp_code[] = {
+ DBCR0_DAC1W | DBCR0_IDM,
+ DBCR0_DAC2W | DBCR0_IDM,
+ DBCR0_DAC1R | DBCR0_IDM,
+ DBCR0_DAC2R | DBCR0_IDM
+ };
+
+#ifndef CONFIG_KVM_BOOKE_HV
+ gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
+ DBCR1_IAC3US | DBCR1_IAC4US;
+ gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
+#else
+ gdbgr->dbcr1 = 0;
+ gdbgr->dbcr2 = 0;
+#endif
+
+ for (n = 0; n < (BP_NUM + WP_NUM); n++) {
+ u32 type = dbg->arch.bp[n].type;
+
+ if (!type)
+ break;
+
+ if (type & (KVMPPC_DEBUG_WATCH_READ |
+ KVMPPC_DEBUG_WATCH_WRITE)) {
+ if (w < WP_NUM) {
+ if (type & KVMPPC_DEBUG_WATCH_READ)
+ gdbgr->dbcr0 |= wp_code[w + 2];
+ if (type & KVMPPC_DEBUG_WATCH_WRITE)
+ gdbgr->dbcr0 |= wp_code[w];
+ gdbgr->dac[w] = dbg->arch.bp[n].addr;
+ w++;
+ }
+ } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
+ if (b < BP_NUM) {
+ gdbgr->dbcr0 |= bp_code[b];
+ gdbgr->iac[b] = dbg->arch.bp[n].addr;
+ b++;
+ }
+ }
+ }
+ }
+ return 0;
}
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index dd9c5d4..2202936 100644
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -39,6 +39,8 @@
#define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4)
#define HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
#define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
+#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
+ DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
#define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS) | \
@@ -52,6 +54,8 @@
(1<<BOOKE_INTERRUPT_PROGRAM) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
+#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
+
.macro __KVM_HANDLER ivor_nr scratch srr0
stw r3, VCPU_GPR(R3)(r4)
stw r5, VCPU_GPR(R5)(r4)
@@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
stw r9, VCPU_FAULT_ESR(r4)
..skip_esr:
+ addi r7, r4, VCPU_HOST_DBG
+ mfspr r9, SPRN_DBCR0
+ lwz r8, KVMPPC_DBG_DBCR0(r7)
+ andis. r9, r9, DBCR0_AC_BITS@h
+ beq skip_load_host_debug
+ li r9, 0
+ mtspr SPRN_DBCR0, r9 /* disable all debug event */
+ lwz r9, KVMPPC_DBG_DBCR1(r7)
+ mtspr SPRN_DBCR1, r9
+ lwz r9, KVMPPC_DBG_DBCR2(r7)
+ mtspr SPRN_DBCR2, r9
+ lwz r9, KVMPPC_DBG_IAC1+4(r7)
+ mtspr SPRN_IAC1, r9
+ lwz r9, KVMPPC_DBG_IAC2+4(r7)
+ mtspr SPRN_IAC2, r9
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ lwz r9, KVMPPC_DBG_IAC3+4(r7)
+ mtspr SPRN_IAC3, r9
+ lwz r9, KVMPPC_DBG_IAC4+4(r7)
+ mtspr SPRN_IAC4, r9
+#endif
+ lwz r9, KVMPPC_DBG_DAC1+4(r7)
+ mtspr SPRN_DAC1, r9
+ lwz r9, KVMPPC_DBG_DAC2+4(r7)
+ mtspr SPRN_DAC2, r9
+skip_load_host_debug:
+ /* Clear h/w DBSR and save current(guest) DBSR */
+ mfspr r9, SPRN_DBSR
+ mtspr SPRN_DBSR, r9
+ isync
+ andi. r7, r6, NEED_DEBUG_SAVE
+ beq skip_dbsr_save
+ /*
+ * If vcpu->guest_debug flag is set then do not check for
+ * shared->msr.DE as this debugging (say by QEMU) does not
+ * depends on shared->msr.de. In these scanerios MSR.DE is
+ * always set using shared_msr and should be handled always.
+ */
+ lwz r7, VCPU_GUEST_DEBUG(r4)
+ cmpwi r7, 0
+ bne skip_save_trap_event
+ PPC_LL r3, VCPU_SHARED(r4)
+#ifndef CONFIG_64BIT
+ lwz r3, (VCPU_SHARED_MSR + 4)(r3)
+#else
+ ld r3, (VCPU_SHARED_MSR)(r3)
+#endif
+ andi. r3, r3, MSR_DE
+ bne skip_save_trap_event
+ andis. r9, r9, DBSR_TIE@h
+skip_save_trap_event:
+ stw r9, VCPU_DBSR(r4)
+skip_dbsr_save:
+ mtspr SPRN_DBCR0, r8
+
/* Save remaining volatile guest register state to vcpu. */
stw r0, VCPU_GPR(R0)(r4)
stw r1, VCPU_GPR(R1)(r4)
@@ -465,6 +524,57 @@ lightweight_exit:
PPC_LD(r3, VCPU_SHARED_SPRG7, r5)
mtspr SPRN_SPRG7W, r3
+ mfmsr r7
+ rlwinm r7, r7, 0, ~MSR_DE
+ mtmsr r7
+ addi r5, r4, VCPU_SHADOW_DBG
+ addi r7, r4, VCPU_HOST_DBG
+ lwz r6, 0(r5)
+ mfspr r8, SPRN_DBCR0
+ andis. r3, r6, DBCR0_AC_BITS@h
+ stw r8, KVMPPC_DBG_DBCR0(r7)
+ beq skip_load_guest_debug
+ mfspr r8, SPRN_DBCR1
+ stw r8, KVMPPC_DBG_DBCR1(r7)
+ mfspr r8, SPRN_DBCR2
+ stw r8, KVMPPC_DBG_DBCR2(r7)
+ mfspr r8, SPRN_IAC1
+ stw r8, KVMPPC_DBG_IAC1+4(r7)
+ mfspr r8, SPRN_IAC2
+ stw r8, KVMPPC_DBG_IAC2+4(r7)
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ mfspr r8, SPRN_IAC3
+ stw r8, KVMPPC_DBG_IAC3+4(r7)
+ mfspr r8, SPRN_IAC4
+ stw r8, KVMPPC_DBG_IAC4+4(r7)
+#endif
+ mfspr r8, SPRN_DAC1
+ stw r8, KVMPPC_DBG_DAC1+4(r7)
+ mfspr r8, SPRN_DAC2
+ stw r8, KVMPPC_DBG_DAC2+4(r7)
+ li r8, 0
+ mtspr SPRN_DBCR0, r8 /* disable all debug event */
+ lwz r8, KVMPPC_DBG_DBCR1(r5)
+ mtspr SPRN_DBCR1, r8
+ lwz r8, KVMPPC_DBG_DBCR2(r5)
+ mtspr SPRN_DBCR2, r8
+ lwz r8, KVMPPC_DBG_IAC1+4(r5)
+ mtspr SPRN_IAC1, r8
+ lwz r8, KVMPPC_DBG_IAC2+4(r5)
+ mtspr SPRN_IAC2, r8
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ lwz r8, KVMPPC_DBG_IAC3+4(r5)
+ mtspr SPRN_IAC3, r8
+ lwz r8, KVMPPC_DBG_IAC4+4(r5)
+ mtspr SPRN_IAC4, r8
+#endif
+ lwz r8, KVMPPC_DBG_DAC1+4(r5)
+ mtspr SPRN_DAC1, r8
+ lwz r8, KVMPPC_DBG_DAC2+4(r5)
+ mtspr SPRN_DAC2, r8
+skip_load_guest_debug:
+ mtspr SPRN_DBCR0, r6
+
#ifdef CONFIG_KVM_EXIT_TIMING
/* save enter time */
1:
diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S
index 099fe82..d021735 100644
--- a/arch/powerpc/kvm/bookehv_interrupts.S
+++ b/arch/powerpc/kvm/bookehv_interrupts.S
@@ -59,6 +59,10 @@
#define NEED_EMU 0x00000001 /* emulation -- save nv regs */
#define NEED_DEAR 0x00000002 /* save faulting DEAR */
#define NEED_ESR 0x00000004 /* save faulting ESR */
+#define NEED_DBSR 0x00000008 /* save DBSR */
+
+#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
+ DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
/*
* On entry:
@@ -198,6 +202,11 @@
PPC_STL r9, VCPU_FAULT_DEAR(r4)
.endif
+ .if \flags & NEED_DBSR
+ mfspr r9, SPRN_DBSR
+ stw r9, VCPU_DBSR(r4)
+ .endif
+
b kvmppc_resume_host
.endm
@@ -292,9 +301,9 @@ kvm_handler BOOKE_INTERRUPT_GUEST_DBELL, SPRN_GSRR0, SPRN_GSRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_GUEST_DBELL_CRIT, \
SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_DEBUG, \
- SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
+ SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, NEED_DBSR
kvm_lvl_handler BOOKE_INTERRUPT_DEBUG, \
- SPRN_SPRG_RSCRATCH_DBG, SPRN_DSRR0, SPRN_DSRR1, 0
+ SPRN_SPRG_RSCRATCH_DBG, SPRN_DSRR0, SPRN_DSRR1, NEED_DBSR
/* Registers:
@@ -304,6 +313,56 @@ kvm_lvl_handler BOOKE_INTERRUPT_DEBUG, \
* r14: KVM exit number
*/
_GLOBAL(kvmppc_resume_host)
+ /*
+ * If guest not used debug facility then hw debug registers
+ * already have proper host values. If guest used debug
+ * facility then restore host debug registers.
+ * No Need to save guest debug registers as they are already intact
+ * in guest/shadow registers.
+ */
+ lwz r9, VCPU_SHADOW_DBG(r4)
+ rlwinm. r8, r9, 0, ~DBCR0_IDM
+ beq skip_load_host_debug
+ lwz r3, VCPU_HOST_DBG(r4)
+ andis. r9, r9, DBCR0_AC_BITS@h
+ li r9, 0
+ mtspr SPRN_DBCR0, r9 /* disable all debug event */
+ beq skip_load_hw_bkpts
+ lwz r7, VCPU_HOST_DBG+KVMPPC_DBG_DBCR1(r4)
+ lwz r8, VCPU_HOST_DBG+KVMPPC_DBG_DBCR2(r4)
+ lwz r9, VCPU_HOST_DBG+KVMPPC_DBG_DBCR4(r4)
+ mtspr SPRN_DBCR1, r7
+ PPC_LD(r6, VCPU_HOST_DBG+KVMPPC_DBG_IAC1, r4)
+ PPC_LD(r7, VCPU_HOST_DBG+KVMPPC_DBG_IAC2, r4)
+ mtspr SPRN_DBCR2, r8
+ mtspr SPRN_DBCR4, r9
+ mtspr SPRN_IAC1, r6
+ mtspr SPRN_IAC2, r7
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ PPC_LD(r7, VCPU_HOST_DBG+KVMPPC_DBG_IAC3, r4)
+ PPC_LD(r8, VCPU_HOST_DBG+KVMPPC_DBG_IAC4, r4)
+ mtspr SPRN_IAC3, r7
+ mtspr SPRN_IAC4, r8
+#endif
+ PPC_LD(r8, VCPU_HOST_DBG+KVMPPC_DBG_DAC1, r4)
+ PPC_LD(r9, VCPU_HOST_DBG+KVMPPC_DBG_DAC2, r4)
+ mtspr SPRN_DAC1, r8
+ mtspr SPRN_DAC2, r9
+skip_load_hw_bkpts:
+ isync
+ /* Clear h/w DBSR and save current(guest) DBSR */
+ mfspr r8, SPRN_DBSR
+ mtspr SPRN_DBSR, r8
+ isync
+ /* Clear EPCR.DUVD and set host DBCR0 */
+ mfspr r8, SPRN_EPCR
+ rlwinm r8, r8, 0, ~SPRN_EPCR_DUVD
+ mtspr SPRN_EPCR, r8
+ isync
+ mtspr SPRN_DBCR0, r3
+ isync
+skip_load_host_debug:
+
/* Save remaining volatile guest register state to vcpu. */
mfspr r3, SPRN_VRSAVE
PPC_STL r0, VCPU_GPR(R0)(r4)
@@ -543,6 +602,84 @@ lightweight_exit:
mtspr SPRN_SPRG6W, r7
mtspr SPRN_SPRG7W, r8
+ mfmsr r7
+ rlwinm r7, r7, 0, ~MSR_DE
+ mtmsr r7
+ /*
+ * Load hw debug registers with guest(shadow) debug registers
+ * if guest is using the debug facility and also set EPCR.DUVD
+ * to not allow debug events in HV mode. Do not change the
+ * debug registers if guest is not using the debug facility.
+ */
+ lwz r6, VCPU_SHADOW_DBG(r4)
+ rlwinm. r7, r6, 0, ~DBCR0_IDM
+ beq skip_load_guest_debug
+ /* Save host DBCR0 */
+ mfspr r8, SPRN_DBCR0
+ stw r8, VCPU_HOST_DBG(r4)
+ /*
+ * Save host DBCR1/2, IACx and DACx and load guest DBCR1/2,
+ * IACx and DACx if guest using hw breakpoint/watchpoints.
+ */
+ andis. r3, r6, DBCR0_AC_BITS@h
+ beq skip_hw_bkpts
+ mfspr r7, SPRN_DBCR1
+ stw r7, VCPU_HOST_DBG+KVMPPC_DBG_DBCR1(r4)
+ mfspr r8, SPRN_DBCR2
+ stw r8, VCPU_HOST_DBG+KVMPPC_DBG_DBCR2(r4)
+ mfspr r7, SPRN_DBCR4
+ stw r7, VCPU_HOST_DBG+KVMPPC_DBG_DBCR4(r4)
+ mfspr r8, SPRN_IAC1
+ PPC_STD(r8, VCPU_HOST_DBG+KVMPPC_DBG_IAC1, r4)
+ mfspr r7, SPRN_IAC2
+ PPC_STD(r7, VCPU_HOST_DBG+KVMPPC_DBG_IAC2, r4)
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ mfspr r8, SPRN_IAC3
+ PPC_STD(r8, VCPU_HOST_DBG+KVMPPC_DBG_IAC3, r4)
+ mfspr r7, SPRN_IAC4
+ PPC_STD(r7, VCPU_HOST_DBG+KVMPPC_DBG_IAC4, r4)
+#endif
+ mfspr r8, SPRN_DAC1
+ PPC_STD(r8, VCPU_HOST_DBG+KVMPPC_DBG_DAC1, r4)
+ mfspr r7, SPRN_DAC2
+ PPC_STD(r7, VCPU_HOST_DBG+KVMPPC_DBG_DAC2, r4)
+ li r8, 0
+ mtspr SPRN_DBCR0, r8 /* disable all debug event */
+ lwz r7, VCPU_SHADOW_DBG+KVMPPC_DBG_DBCR1(r4)
+ lwz r8, VCPU_SHADOW_DBG+KVMPPC_DBG_DBCR2(r4)
+ lwz r9, VCPU_SHADOW_DBG+KVMPPC_DBG_DBCR4(r4)
+ mtspr SPRN_DBCR1, r7
+ PPC_LD(r7, VCPU_SHADOW_DBG+KVMPPC_DBG_IAC1, r4)
+ PPC_LD(r3, VCPU_SHADOW_DBG+KVMPPC_DBG_IAC2, r4)
+ mtspr SPRN_DBCR2, r8
+ mtspr SPRN_DBCR4, r9
+ mtspr SPRN_IAC1, r7
+ mtspr SPRN_IAC2, r3
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ PPC_LD(r7, VCPU_SHADOW_DBG+KVMPPC_DBG_IAC3, r4)
+ PPC_LD(r8, VCPU_SHADOW_DBG+KVMPPC_DBG_IAC4, r4)
+ mtspr SPRN_IAC3, r7
+ mtspr SPRN_IAC4, r8
+#endif
+ PPC_LD(r7, VCPU_SHADOW_DBG+KVMPPC_DBG_DAC1, r4)
+ PPC_LD(r8, VCPU_SHADOW_DBG+KVMPPC_DBG_DAC2, r4)
+ mtspr SPRN_DAC1, r7
+ mtspr SPRN_DAC2, r8
+skip_hw_bkpts:
+ /* Set EPCR.DUVD and guest DBCR0 */
+ mfspr r7, SPRN_EPCR
+ oris r7, r7, SPRN_EPCR_DUVD@h
+ mtspr SPRN_EPCR, r7
+ isync
+ /* Clear if any deferred debug event */
+ mfspr r8, SPRN_DBSR
+ mtspr SPRN_DBSR, r8
+ isync
+ /* Restore guest DBCR */
+ mtspr SPRN_DBCR0, r6
+ isync
+skip_load_guest_debug:
+
/* Load some guest volatiles. */
PPC_LL r3, VCPU_LR(r4)
PPC_LL r5, VCPU_XER(r4)
diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index 1f89d26..f5fc6f5 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -182,8 +182,7 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu)
{
struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
- vcpu->arch.shadow_epcr = SPRN_EPCR_DSIGS | SPRN_EPCR_DGTMI | \
- SPRN_EPCR_DUVD;
+ vcpu->arch.shadow_epcr = SPRN_EPCR_DSIGS | SPRN_EPCR_DGTMI;
#ifdef CONFIG_64BIT
vcpu->arch.shadow_epcr |= SPRN_EPCR_ICM;
#endif
--
1.7.0.4
^ permalink raw reply related [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-08-21 13:52 ` [PATCH 6/6] KVM: booke/bookehv: Add debug stub support Bharat Bhushan
@ 2012-09-05 23:23 ` Scott Wood
2012-09-05 23:27 ` Scott Wood
2012-09-24 16:20 ` Alexander Graf
1 sibling, 1 reply; 32+ messages in thread
From: Scott Wood @ 2012-09-05 23:23 UTC (permalink / raw)
To: Bharat Bhushan; +Cc: kvm-ppc, kvm, agraf, Bharat Bhushan
On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
> This patch adds the debug stub support on booke/bookehv.
> Now QEMU debug stub can use hw breakpoint, watchpoint and
> software breakpoint to debug guest.
>
> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> ---
> arch/powerpc/include/asm/kvm.h | 29 ++++++-
> arch/powerpc/include/asm/kvm_host.h | 5 +
> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++----
> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
> arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++++++++++-
> arch/powerpc/kvm/e500mc.c | 3 +-
> 7 files changed, 435 insertions(+), 23 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
> index 61b197e..53479ea 100644
> --- a/arch/powerpc/include/asm/kvm.h
> +++ b/arch/powerpc/include/asm/kvm.h
> @@ -25,6 +25,7 @@
> /* Select powerpc specific features in <linux/kvm.h> */
> #define __KVM_HAVE_SPAPR_TCE
> #define __KVM_HAVE_PPC_SMT
> +#define __KVM_HAVE_GUEST_DEBUG
>
> struct kvm_regs {
> __u64 pc;
> @@ -264,7 +265,31 @@ struct kvm_fpu {
> __u64 fpr[32];
> };
>
> +
> +/*
> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
> + * software breakpoint.
> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
> + * for KVM_DEBUG_EXIT.
> + */
> +#define KVMPPC_DEBUG_NONE 0x0
> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> struct kvm_debug_exit_arch {
That says "arch", but it's not in an arch-specific file.
> + __u64 pc;
> + /*
> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
> + * exit is not handled (say not h/w breakpoint or software breakpoint
> + * set for this address) by qemu then it is supposed to inject this
> + * exception to guest.
> + */
> + __u32 exception;
> + /*
> + * exiting to userspace because of h/w breakpoint, watchpoint
> + * (read, write or both) and software breakpoint.
> + */
> + __u32 status;
> };
What does "exception number" mean in a generic API?
What values can go in "status"?
> + addi r7, r4, VCPU_HOST_DBG
> + mfspr r9, SPRN_DBCR0
> + lwz r8, KVMPPC_DBG_DBCR0(r7)
> + andis. r9, r9, DBCR0_AC_BITS@h
> + beq skip_load_host_debug
> + li r9, 0
> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
> + lwz r9, KVMPPC_DBG_DBCR1(r7)
> + mtspr SPRN_DBCR1, r9
> + lwz r9, KVMPPC_DBG_DBCR2(r7)
> + mtspr SPRN_DBCR2, r9
> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
> + mtspr SPRN_IAC1, r9
> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
> + mtspr SPRN_IAC2, r9
> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
> + mtspr SPRN_IAC3, r9
> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
> + mtspr SPRN_IAC4, r9
> +#endif
What if CONFIG_PPC_ADV_DEBUG_REGS isn't set?
-Scott
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 5/6] booke: Added DBCR4 SPR number
2012-08-21 13:51 ` [PATCH 5/6] booke: Added DBCR4 SPR number Bharat Bhushan
@ 2012-09-05 23:24 ` Scott Wood
0 siblings, 0 replies; 32+ messages in thread
From: Scott Wood @ 2012-09-05 23:24 UTC (permalink / raw)
To: Bharat Bhushan; +Cc: kvm-ppc, kvm, agraf, Bharat Bhushan
On 08/21/2012 08:51 AM, Bharat Bhushan wrote:
> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> ---
> arch/powerpc/include/asm/reg_booke.h | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/reg_booke.h b/arch/powerpc/include/asm/reg_booke.h
> index e07e6af..b417de3 100644
> --- a/arch/powerpc/include/asm/reg_booke.h
> +++ b/arch/powerpc/include/asm/reg_booke.h
> @@ -56,6 +56,7 @@
> #define SPRN_SPRG7W 0x117 /* Special Purpose Register General 7 Write */
> #define SPRN_EPCR 0x133 /* Embedded Processor Control Register */
> #define SPRN_DBCR2 0x136 /* Debug Control Register 2 */
> +#define SPRN_DBCR4 0x233 /* Debug Control Register 4 */
> #define SPRN_MSRP 0x137 /* MSR Protect Register */
> #define SPRN_IAC3 0x13A /* Instruction Address Compare 3 */
> #define SPRN_IAC4 0x13B /* Instruction Address Compare 4 */
>
Please keep this in numerical order.
-Scott
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-05 23:23 ` Scott Wood
@ 2012-09-05 23:27 ` Scott Wood
2012-09-06 14:56 ` Bhushan Bharat-R65777
0 siblings, 1 reply; 32+ messages in thread
From: Scott Wood @ 2012-09-05 23:27 UTC (permalink / raw)
To: Bharat Bhushan; +Cc: kvm-ppc, kvm, agraf, Bharat Bhushan
On 09/05/2012 06:23 PM, Scott Wood wrote:
> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>> This patch adds the debug stub support on booke/bookehv.
>> Now QEMU debug stub can use hw breakpoint, watchpoint and
>> software breakpoint to debug guest.
>>
>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>> ---
>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>> arch/powerpc/include/asm/kvm_host.h | 5 +
>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++----
>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>> arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++++++++++-
>> arch/powerpc/kvm/e500mc.c | 3 +-
>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
>> index 61b197e..53479ea 100644
>> --- a/arch/powerpc/include/asm/kvm.h
>> +++ b/arch/powerpc/include/asm/kvm.h
>> @@ -25,6 +25,7 @@
>> /* Select powerpc specific features in <linux/kvm.h> */
>> #define __KVM_HAVE_SPAPR_TCE
>> #define __KVM_HAVE_PPC_SMT
>> +#define __KVM_HAVE_GUEST_DEBUG
>>
>> struct kvm_regs {
>> __u64 pc;
>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>> __u64 fpr[32];
>> };
>>
>> +
>> +/*
>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>> + * software breakpoint.
>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>> + * for KVM_DEBUG_EXIT.
>> + */
>> +#define KVMPPC_DEBUG_NONE 0x0
>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>> struct kvm_debug_exit_arch {
>
> That says "arch", but it's not in an arch-specific file.
Sigh, I can't read today apparently.
>> + __u64 pc;
>> + /*
>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>> + * set for this address) by qemu then it is supposed to inject this
>> + * exception to guest.
>> + */
>> + __u32 exception;
>> + /*
>> + * exiting to userspace because of h/w breakpoint, watchpoint
>> + * (read, write or both) and software breakpoint.
>> + */
>> + __u32 status;
>> };
>
> What does "exception number" mean in a generic API?
Still, "exception number" is not a well-defined concept powerpc-wide.
-Scott
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-05 23:27 ` Scott Wood
@ 2012-09-06 14:56 ` Bhushan Bharat-R65777
2012-09-06 22:56 ` Scott Wood
0 siblings, 1 reply; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-09-06 14:56 UTC (permalink / raw)
To: Wood Scott-B07421
Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, agraf@suse.de
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Thursday, September 06, 2012 4:57 AM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
> R65777
> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>
> On 09/05/2012 06:23 PM, Scott Wood wrote:
> > On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
> >> This patch adds the debug stub support on booke/bookehv.
> >> Now QEMU debug stub can use hw breakpoint, watchpoint and software
> >> breakpoint to debug guest.
> >>
> >> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> >> ---
> >> arch/powerpc/include/asm/kvm.h | 29 ++++++-
> >> arch/powerpc/include/asm/kvm_host.h | 5 +
> >> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
> >> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
> --
> >> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
> >> arch/powerpc/kvm/bookehv_interrupts.S | 141
> +++++++++++++++++++++++++++++++-
> >> arch/powerpc/kvm/e500mc.c | 3 +-
> >> 7 files changed, 435 insertions(+), 23 deletions(-)
> >>
> >> diff --git a/arch/powerpc/include/asm/kvm.h
> >> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
> >> --- a/arch/powerpc/include/asm/kvm.h
> >> +++ b/arch/powerpc/include/asm/kvm.h
> >> @@ -25,6 +25,7 @@
> >> /* Select powerpc specific features in <linux/kvm.h> */ #define
> >> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
> >> +#define __KVM_HAVE_GUEST_DEBUG
> >>
> >> struct kvm_regs {
> >> __u64 pc;
> >> @@ -264,7 +265,31 @@ struct kvm_fpu {
> >> __u64 fpr[32];
> >> };
> >>
> >> +
> >> +/*
> >> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
> >> + * software breakpoint.
> >> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
> >> + * for KVM_DEBUG_EXIT.
> >> + */
> >> +#define KVMPPC_DEBUG_NONE 0x0
> >> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> >> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> >> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> >> struct kvm_debug_exit_arch {
> >
> > That says "arch", but it's not in an arch-specific file.
>
> Sigh, I can't read today apparently.
>
> >> + __u64 pc;
> >> + /*
> >> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
> >> + * exit is not handled (say not h/w breakpoint or software breakpoint
> >> + * set for this address) by qemu then it is supposed to inject this
> >> + * exception to guest.
> >> + */
> >> + __u32 exception;
> >> + /*
> >> + * exiting to userspace because of h/w breakpoint, watchpoint
> >> + * (read, write or both) and software breakpoint.
> >> + */
> >> + __u32 status;
> >> };
> >
> > What does "exception number" mean in a generic API?
>
> Still, "exception number" is not a well-defined concept powerpc-wide.
Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
Thanks
-Bharat
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-06 14:56 ` Bhushan Bharat-R65777
@ 2012-09-06 22:56 ` Scott Wood
2012-09-24 14:46 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Scott Wood @ 2012-09-06 22:56 UTC (permalink / raw)
To: Bhushan Bharat-R65777
Cc: Wood Scott-B07421, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
agraf@suse.de
On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>
>
>> -----Original Message-----
>> From: Wood Scott-B07421
>> Sent: Thursday, September 06, 2012 4:57 AM
>> To: Bhushan Bharat-R65777
>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>> R65777
>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>
>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>> This patch adds the debug stub support on booke/bookehv.
>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>> breakpoint to debug guest.
>>>>
>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>> ---
>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>> --
>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>> +++++++++++++++++++++++++++++++-
>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>> @@ -25,6 +25,7 @@
>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>
>>>> struct kvm_regs {
>>>> __u64 pc;
>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>> __u64 fpr[32];
>>>> };
>>>>
>>>> +
>>>> +/*
>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>> + * software breakpoint.
>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>> + * for KVM_DEBUG_EXIT.
>>>> + */
>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>> struct kvm_debug_exit_arch {
>>>
>>> That says "arch", but it's not in an arch-specific file.
>>
>> Sigh, I can't read today apparently.
>>
>>>> + __u64 pc;
>>>> + /*
>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>> + * set for this address) by qemu then it is supposed to inject this
>>>> + * exception to guest.
>>>> + */
>>>> + __u32 exception;
>>>> + /*
>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>> + * (read, write or both) and software breakpoint.
>>>> + */
>>>> + __u32 status;
>>>> };
>>>
>>> What does "exception number" mean in a generic API?
>>
>> Still, "exception number" is not a well-defined concept powerpc-wide.
>
> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>
> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
We can pass up the exception type; it just needs more documentation
about what exactly you're referring to, and probably some enumeration
that says which exception numberspace it is.
For booke the exception number should probably be related to the fixed
offsets rather than the IVOR number, as IVORs are phased out.
-Scott
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-06 22:56 ` Scott Wood
@ 2012-09-24 14:46 ` Alexander Graf
2012-09-25 10:38 ` Jan Kiszka
0 siblings, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-09-24 14:46 UTC (permalink / raw)
To: Scott Wood
Cc: Bhushan Bharat-R65777, Wood Scott-B07421, kvm-ppc, KVM list,
Jan Kiszka
On 07.09.2012, at 00:56, Scott Wood wrote:
> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>
>>
>>> -----Original Message-----
>>> From: Wood Scott-B07421
>>> Sent: Thursday, September 06, 2012 4:57 AM
>>> To: Bhushan Bharat-R65777
>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>> R65777
>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>
>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>> breakpoint to debug guest.
>>>>>
>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>> ---
>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>> --
>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>> +++++++++++++++++++++++++++++++-
>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>
>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>> @@ -25,6 +25,7 @@
>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>
>>>>> struct kvm_regs {
>>>>> __u64 pc;
>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>> __u64 fpr[32];
>>>>> };
>>>>>
>>>>> +
>>>>> +/*
>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>> + * software breakpoint.
>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>> + * for KVM_DEBUG_EXIT.
>>>>> + */
>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>> struct kvm_debug_exit_arch {
>>>>
>>>> That says "arch", but it's not in an arch-specific file.
>>>
>>> Sigh, I can't read today apparently.
>>>
>>>>> + __u64 pc;
>>>>> + /*
>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>> + * exception to guest.
>>>>> + */
>>>>> + __u32 exception;
>>>>> + /*
>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>> + * (read, write or both) and software breakpoint.
>>>>> + */
>>>>> + __u32 status;
>>>>> };
>>>>
>>>> What does "exception number" mean in a generic API?
>>>
>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>
>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>
>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>
> We can pass up the exception type; it just needs more documentation
> about what exactly you're referring to, and probably some enumeration
> that says which exception numberspace it is.
>
> For booke the exception number should probably be related to the fixed
> offsets rather than the IVOR number, as IVORs are phased out.
Jan, I would like to get your comment on this one.
Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
2012-08-21 13:51 ` [PATCH 4/6] KVM: PPC: debug stub interface parameter defined Bharat Bhushan
@ 2012-09-24 15:38 ` Alexander Graf
2012-10-04 7:14 ` Bhushan Bharat-R65777
2012-10-04 7:37 ` Bhushan Bharat-R65777
0 siblings, 2 replies; 32+ messages in thread
From: Alexander Graf @ 2012-09-24 15:38 UTC (permalink / raw)
To: Bharat Bhushan; +Cc: kvm-ppc, kvm, Bharat Bhushan
On 21.08.2012, at 15:51, Bharat Bhushan wrote:
> This patch defines the interface parameter for KVM_SET_GUEST_DEBUG
> ioctl support. Follow up patches will use this for setting up
> hardware breakpoints, watchpoints and software breakpoints.
>
> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> ---
> arch/powerpc/include/asm/kvm.h | 33 +++++++++++++++++++++++++++++++++
> arch/powerpc/kvm/book3s.c | 6 ++++++
> arch/powerpc/kvm/booke.c | 6 ++++++
> arch/powerpc/kvm/powerpc.c | 6 ------
> 4 files changed, 45 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
> index 3c14202..61b197e 100644
> --- a/arch/powerpc/include/asm/kvm.h
> +++ b/arch/powerpc/include/asm/kvm.h
> @@ -269,8 +269,41 @@ struct kvm_debug_exit_arch {
>
> /* for KVM_SET_GUEST_DEBUG */
> struct kvm_guest_debug_arch {
> + struct {
> + /* H/W breakpoint/watchpoint address */
> + __u64 addr;
> + /*
> + * Type denotes h/w breakpoint, read watchpoint, write
> + * watchpoint or watchpoint (both read and write).
> + */
> +#define KVMPPC_DEBUG_NOTYPE 0x0
> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> + __u32 type;
> + __u32 pad1;
Why the padding?
> + __u64 pad2;
> + } bp[16];
Why 16?
> };
>
> +/* Debug related defines */
> +/*
> + * kvm_guest_debug->control is a 32 bit field. The lower 16 bits are generic
> + * and upper 16 bits are architecture specific. Architecture specific defines
> + * that ioctl is for setting hardware breakpoint or software breakpoint.
> + */
> +#define KVM_GUESTDBG_USE_SW_BP 0x00010000
> +#define KVM_GUESTDBG_USE_HW_BP 0x00020000
> +
> +/* When setting software breakpoint, Change the software breakpoint
> + * instruction to special trap instruction and set KVM_GUESTDBG_USE_SW_BP
> + * flag in kvm_guest_debug->control. KVM does keep track of software
> + * breakpoints. So when KVM_GUESTDBG_USE_SW_BP flag is set and special trap
> + * instruction is executed by guest then exit to userspace.
> + * NOTE: A Nice interface can be added to get the special trap instruction.
> + */
> +#define KVMPPC_INST_GUEST_GDB 0x7C00021C /* ehpriv OC=0 */
This definitely has to be passed to user space (which writes that instruction into guest phys memory). Other PPC subarchs will use different instructions. Just model it as a read-only ONE_REG.
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-08-21 13:52 ` [PATCH 6/6] KVM: booke/bookehv: Add debug stub support Bharat Bhushan
2012-09-05 23:23 ` Scott Wood
@ 2012-09-24 16:20 ` Alexander Graf
2012-10-04 11:06 ` Bhushan Bharat-R65777
1 sibling, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-09-24 16:20 UTC (permalink / raw)
To: Bharat Bhushan; +Cc: kvm-ppc, kvm, Bharat Bhushan
On 21.08.2012, at 15:52, Bharat Bhushan wrote:
> This patch adds the debug stub support on booke/bookehv.
> Now QEMU debug stub can use hw breakpoint, watchpoint and
> software breakpoint to debug guest.
>
> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> ---
> arch/powerpc/include/asm/kvm.h | 29 ++++++-
> arch/powerpc/include/asm/kvm_host.h | 5 +
> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++----
> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
> arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++++++++++-
> arch/powerpc/kvm/e500mc.c | 3 +-
> 7 files changed, 435 insertions(+), 23 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
> index 61b197e..53479ea 100644
> --- a/arch/powerpc/include/asm/kvm.h
> +++ b/arch/powerpc/include/asm/kvm.h
> @@ -25,6 +25,7 @@
> /* Select powerpc specific features in <linux/kvm.h> */
> #define __KVM_HAVE_SPAPR_TCE
> #define __KVM_HAVE_PPC_SMT
> +#define __KVM_HAVE_GUEST_DEBUG
>
> struct kvm_regs {
> __u64 pc;
> @@ -264,7 +265,31 @@ struct kvm_fpu {
> __u64 fpr[32];
> };
>
> +
> +/*
> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
> + * software breakpoint.
> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
> + * for KVM_DEBUG_EXIT.
> + */
> +#define KVMPPC_DEBUG_NONE 0x0
> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> struct kvm_debug_exit_arch {
> + __u64 pc;
> + /*
> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
> + * exit is not handled (say not h/w breakpoint or software breakpoint
> + * set for this address) by qemu then it is supposed to inject this
> + * exception to guest.
> + */
> + __u32 exception;
> + /*
> + * exiting to userspace because of h/w breakpoint, watchpoint
> + * (read, write or both) and software breakpoint.
> + */
> + __u32 status;
> };
>
> /* for KVM_SET_GUEST_DEBUG */
> @@ -276,10 +301,6 @@ struct kvm_guest_debug_arch {
> * Type denotes h/w breakpoint, read watchpoint, write
> * watchpoint or watchpoint (both read and write).
> */
> -#define KVMPPC_DEBUG_NOTYPE 0x0
> -#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> -#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> -#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> __u32 type;
> __u32 pad1;
> __u64 pad2;
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index c7219c1..3ba465a 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -496,7 +496,12 @@ struct kvm_vcpu_arch {
> u32 mmucfg;
> u32 epr;
> u32 crit_save;
> + /* guest debug registers*/
> struct kvmppc_booke_debug_reg dbg_reg;
> + /* shadow debug registers */
> + struct kvmppc_booke_debug_reg shadow_dbg_reg;
> + /* host debug registers*/
> + struct kvmppc_booke_debug_reg host_dbg_reg;
> #endif
> gpa_t paddr_accessed;
> gva_t vaddr_accessed;
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index 555448e..6987821 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -564,6 +564,32 @@ int main(void)
> DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
> DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
> DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
> + DEFINE(VCPU_DBSR, offsetof(struct kvm_vcpu, arch.dbsr));
> + DEFINE(VCPU_SHADOW_DBG, offsetof(struct kvm_vcpu, arch.shadow_dbg_reg));
> + DEFINE(VCPU_HOST_DBG, offsetof(struct kvm_vcpu, arch.host_dbg_reg));
> + DEFINE(KVMPPC_DBG_DBCR0, offsetof(struct kvmppc_booke_debug_reg,
> + dbcr0));
> + DEFINE(KVMPPC_DBG_DBCR1, offsetof(struct kvmppc_booke_debug_reg,
> + dbcr1));
> + DEFINE(KVMPPC_DBG_DBCR2, offsetof(struct kvmppc_booke_debug_reg,
> + dbcr2));
> +#ifdef CONFIG_KVM_E500MC
> + DEFINE(KVMPPC_DBG_DBCR4, offsetof(struct kvmppc_booke_debug_reg,
> + dbcr4));
> +#endif
> + DEFINE(KVMPPC_DBG_IAC1, offsetof(struct kvmppc_booke_debug_reg,
> + iac[0]));
> + DEFINE(KVMPPC_DBG_IAC2, offsetof(struct kvmppc_booke_debug_reg,
> + iac[1]));
> + DEFINE(KVMPPC_DBG_IAC3, offsetof(struct kvmppc_booke_debug_reg,
> + iac[2]));
> + DEFINE(KVMPPC_DBG_IAC4, offsetof(struct kvmppc_booke_debug_reg,
> + iac[3]));
> + DEFINE(KVMPPC_DBG_DAC1, offsetof(struct kvmppc_booke_debug_reg,
> + dac[0]));
> + DEFINE(KVMPPC_DBG_DAC2, offsetof(struct kvmppc_booke_debug_reg,
> + dac[1]));
> + DEFINE(VCPU_GUEST_DEBUG, offsetof(struct kvm_vcpu, guest_debug));
> #endif /* CONFIG_PPC_BOOK3S */
> #endif /* CONFIG_KVM */
>
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index dd0e5b8..4d82e34 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -132,6 +132,9 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)
>
> #ifdef CONFIG_KVM_BOOKE_HV
> new_msr |= MSR_GS;
> +
> + if (vcpu->guest_debug)
> + new_msr |= MSR_DE;
> #endif
>
> vcpu->arch.shared->msr = new_msr;
> @@ -667,10 +670,21 @@ out:
> return ret;
> }
>
> -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
> +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> + int exit_nr)
> {
> enum emulation_result er;
>
> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
> + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
This belongs into the normal emulation code path, behind the same switch() that everything else goes through.
> + run->exit_reason = KVM_EXIT_DEBUG;
> + run->debug.arch.pc = vcpu->arch.pc;
> + run->debug.arch.exception = exit_nr;
> + run->debug.arch.status = 0;
> + kvmppc_account_exit(vcpu, DEBUG_EXITS);
> + return RESUME_HOST;
> + }
> +
> er = kvmppc_emulate_instruction(run, vcpu);
> switch (er) {
> case EMULATE_DONE:
> @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
> default:
> BUG();
> }
> +
> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
> + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
I don't understand how this is supposed to work. When we enable singlestep, why would we end up in emulation_exit()?
> + run->exit_reason = KVM_EXIT_DEBUG;
> + return RESUME_HOST;
> + }
> +}
> +
> +static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu *vcpu)
> +{
> + u32 dbsr;
> +
> +#ifndef CONFIG_KVM_BOOKE_HV
> + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
> + vcpu->arch.pc = mfspr(SPRN_DSRR0);
> + else
> + vcpu->arch.pc = mfspr(SPRN_CSRR0);
> +#endif
Why doesn't this get handled in the asm code that recovers from the respective exceptions?
> + dbsr = vcpu->arch.dbsr;
> +
> + run->debug.arch.pc = vcpu->arch.pc;
> + run->debug.arch.status = 0;
> + vcpu->arch.dbsr = 0;
> +
> + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
> + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
> + } else {
> + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
> + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
> + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
> + }
Mind to explain the guest register sharing mechanism you are envisioning? Which registers are used by the guest? Which are used by the host? Who decides what gets used by whom?
> +
> + return RESUME_HOST;
> }
>
> static void kvmppc_fill_pt_regs(struct pt_regs *regs)
> @@ -843,7 +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> break;
>
> case BOOKE_INTERRUPT_HV_PRIV:
> - r = emulation_exit(run, vcpu);
> + r = emulation_exit(run, vcpu, exit_nr);
> break;
>
> case BOOKE_INTERRUPT_PROGRAM:
> @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> break;
> }
>
> - r = emulation_exit(run, vcpu);
> + r = emulation_exit(run, vcpu, exit_nr);
> break;
>
> case BOOKE_INTERRUPT_FP_UNAVAIL:
> @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> }
>
> case BOOKE_INTERRUPT_DEBUG: {
> - u32 dbsr;
> -
> - vcpu->arch.pc = mfspr(SPRN_CSRR0);
> -
> - /* clear IAC events in DBSR register */
> - dbsr = mfspr(SPRN_DBSR);
> - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
> - mtspr(SPRN_DBSR, dbsr);
> -
> - run->exit_reason = KVM_EXIT_DEBUG;
> + r = kvmppc_handle_debug(run, vcpu);
> + if (r == RESUME_HOST) {
> + run->debug.arch.exception = exit_nr;
> + run->exit_reason = KVM_EXIT_DEBUG;
> + }
> kvmppc_account_exit(vcpu, DEBUG_EXITS);
> - r = RESUME_HOST;
> break;
> }
>
> @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
> return r;
> }
>
> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
> +
> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
> struct kvm_guest_debug *dbg)
> {
> - return -EINVAL;
> +
> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
> + /* Clear All debug events */
> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> + vcpu->guest_debug = 0;
> + return 0;
> + }
> +
> + vcpu->guest_debug = dbg->control;
> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> +
> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
> +
> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
> + struct kvmppc_booke_debug_reg *gdbgr =
> + &(vcpu->arch.shadow_dbg_reg);
> + int n, b = 0, w = 0;
> + const u32 bp_code[] = {
> + DBCR0_IAC1 | DBCR0_IDM,
> + DBCR0_IAC2 | DBCR0_IDM,
> + DBCR0_IAC3 | DBCR0_IDM,
> + DBCR0_IAC4 | DBCR0_IDM
> + };
> + const u32 wp_code[] = {
> + DBCR0_DAC1W | DBCR0_IDM,
> + DBCR0_DAC2W | DBCR0_IDM,
> + DBCR0_DAC1R | DBCR0_IDM,
> + DBCR0_DAC2R | DBCR0_IDM
> + };
> +
> +#ifndef CONFIG_KVM_BOOKE_HV
> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
> + DBCR1_IAC3US | DBCR1_IAC4US;
> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
> +#else
> + gdbgr->dbcr1 = 0;
> + gdbgr->dbcr2 = 0;
> +#endif
> +
> + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
> + u32 type = dbg->arch.bp[n].type;
> +
> + if (!type)
> + break;
> +
> + if (type & (KVMPPC_DEBUG_WATCH_READ |
> + KVMPPC_DEBUG_WATCH_WRITE)) {
> + if (w < WP_NUM) {
> + if (type & KVMPPC_DEBUG_WATCH_READ)
> + gdbgr->dbcr0 |= wp_code[w + 2];
> + if (type & KVMPPC_DEBUG_WATCH_WRITE)
> + gdbgr->dbcr0 |= wp_code[w];
> + gdbgr->dac[w] = dbg->arch.bp[n].addr;
> + w++;
> + }
> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
> + if (b < BP_NUM) {
> + gdbgr->dbcr0 |= bp_code[b];
> + gdbgr->iac[b] = dbg->arch.bp[n].addr;
> + b++;
> + }
> + }
> + }
> + }
> + return 0;
> }
>
> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
> diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
> index dd9c5d4..2202936 100644
> --- a/arch/powerpc/kvm/booke_interrupts.S
> +++ b/arch/powerpc/kvm/booke_interrupts.S
> @@ -39,6 +39,8 @@
> #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4)
> #define HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
> #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
> +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
> + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
>
> #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
> (1<<BOOKE_INTERRUPT_DTLB_MISS) | \
> @@ -52,6 +54,8 @@
> (1<<BOOKE_INTERRUPT_PROGRAM) | \
> (1<<BOOKE_INTERRUPT_DTLB_MISS))
>
> +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
> +
> .macro __KVM_HANDLER ivor_nr scratch srr0
> stw r3, VCPU_GPR(R3)(r4)
> stw r5, VCPU_GPR(R5)(r4)
> @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
> stw r9, VCPU_FAULT_ESR(r4)
> ..skip_esr:
>
> + addi r7, r4, VCPU_HOST_DBG
> + mfspr r9, SPRN_DBCR0
> + lwz r8, KVMPPC_DBG_DBCR0(r7)
> + andis. r9, r9, DBCR0_AC_BITS@h
> + beq skip_load_host_debug
> + li r9, 0
> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
> + lwz r9, KVMPPC_DBG_DBCR1(r7)
> + mtspr SPRN_DBCR1, r9
> + lwz r9, KVMPPC_DBG_DBCR2(r7)
> + mtspr SPRN_DBCR2, r9
> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
> + mtspr SPRN_IAC1, r9
> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
> + mtspr SPRN_IAC2, r9
> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
> + mtspr SPRN_IAC3, r9
> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
> + mtspr SPRN_IAC4, r9
> +#endif
> + lwz r9, KVMPPC_DBG_DAC1+4(r7)
> + mtspr SPRN_DAC1, r9
> + lwz r9, KVMPPC_DBG_DAC2+4(r7)
Yikes. Please move this into a struct, similar to how the MSR save/restore happens on x86.
Also, these are 64-bit loads and stores, no?
> + mtspr SPRN_DAC2, r9
> +skip_load_host_debug:
> + /* Clear h/w DBSR and save current(guest) DBSR */
> + mfspr r9, SPRN_DBSR
> + mtspr SPRN_DBSR, r9
> + isync
> + andi. r7, r6, NEED_DEBUG_SAVE
> + beq skip_dbsr_save
> + /*
> + * If vcpu->guest_debug flag is set then do not check for
> + * shared->msr.DE as this debugging (say by QEMU) does not
> + * depends on shared->msr.de. In these scanerios MSR.DE is
> + * always set using shared_msr and should be handled always.
> + */
> + lwz r7, VCPU_GUEST_DEBUG(r4)
> + cmpwi r7, 0
> + bne skip_save_trap_event
> + PPC_LL r3, VCPU_SHARED(r4)
> +#ifndef CONFIG_64BIT
> + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
> +#else
> + ld r3, (VCPU_SHARED_MSR)(r3)
> +#endif
Didn't we have 64-bit access helpers for these?
Also this shouldn't happen in the entry/exit code. We have shadow_msr for these purposes.
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct
2012-08-21 13:51 ` [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct Bharat Bhushan
@ 2012-09-24 16:27 ` Alexander Graf
2012-10-04 6:50 ` Bhushan Bharat-R65777
0 siblings, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-09-24 16:27 UTC (permalink / raw)
To: Bharat Bhushan; +Cc: kvm-ppc, kvm, Bharat Bhushan
On 21.08.2012, at 15:51, Bharat Bhushan wrote:
> Like other places, use thread_struct to get vcpu reference.
Please remove the definition of SPRN_SPRG_R/WVCPU as well.
Alex
>
> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> ---
> arch/powerpc/kernel/asm-offsets.c | 2 +-
> arch/powerpc/kvm/booke_interrupts.S | 6 ++----
> 2 files changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index 85b05c4..fbb999c 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -116,7 +116,7 @@ int main(void)
> #ifdef CONFIG_KVM_BOOK3S_32_HANDLER
> DEFINE(THREAD_KVM_SVCPU, offsetof(struct thread_struct, kvm_shadow_vcpu));
> #endif
> -#ifdef CONFIG_KVM_BOOKE_HV
> +#if defined(CONFIG_KVM) && defined(CONFIG_BOOKE)
> DEFINE(THREAD_KVM_VCPU, offsetof(struct thread_struct, kvm_vcpu));
> #endif
>
> diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
> index bb46b32..ca16d57 100644
> --- a/arch/powerpc/kvm/booke_interrupts.S
> +++ b/arch/powerpc/kvm/booke_interrupts.S
> @@ -56,7 +56,8 @@
> _GLOBAL(kvmppc_handler_\ivor_nr)
> /* Get pointer to vcpu and record exit number. */
> mtspr \scratch , r4
> - mfspr r4, SPRN_SPRG_RVCPU
> + mfspr r4, SPRN_SPRG_THREAD
> + lwz r4, THREAD_KVM_VCPU(r4)
> stw r3, VCPU_GPR(R3)(r4)
> stw r5, VCPU_GPR(R5)(r4)
> stw r6, VCPU_GPR(R6)(r4)
> @@ -402,9 +403,6 @@ lightweight_exit:
> lwz r8, kvmppc_booke_handlers@l(r8)
> mtspr SPRN_IVPR, r8
>
> - /* Save vcpu pointer for the exception handlers. */
> - mtspr SPRN_SPRG_WVCPU, r4
> -
> lwz r5, VCPU_SHARED(r4)
>
> /* Can't switch the stack pointer until after IVPR is switched,
> --
> 1.7.0.4
>
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-24 14:46 ` Alexander Graf
@ 2012-09-25 10:38 ` Jan Kiszka
2012-09-25 10:47 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Jan Kiszka @ 2012-09-25 10:38 UTC (permalink / raw)
To: Alexander Graf
Cc: Scott Wood, Bhushan Bharat-R65777, Wood Scott-B07421,
kvm-ppc@vger.kernel.org, KVM list
On 2012-09-24 16:46, Alexander Graf wrote:
>
> On 07.09.2012, at 00:56, Scott Wood wrote:
>
>> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>>
>>>
>>>> -----Original Message-----
>>>> From: Wood Scott-B07421
>>>> Sent: Thursday, September 06, 2012 4:57 AM
>>>> To: Bhushan Bharat-R65777
>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>>> R65777
>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>
>>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>>> breakpoint to debug guest.
>>>>>>
>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>>> ---
>>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>>> --
>>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>>> +++++++++++++++++++++++++++++++-
>>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>>
>>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>>> @@ -25,6 +25,7 @@
>>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>>
>>>>>> struct kvm_regs {
>>>>>> __u64 pc;
>>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>>> __u64 fpr[32];
>>>>>> };
>>>>>>
>>>>>> +
>>>>>> +/*
>>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>>> + * software breakpoint.
>>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>>> + * for KVM_DEBUG_EXIT.
>>>>>> + */
>>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>>> struct kvm_debug_exit_arch {
>>>>>
>>>>> That says "arch", but it's not in an arch-specific file.
>>>>
>>>> Sigh, I can't read today apparently.
>>>>
>>>>>> + __u64 pc;
>>>>>> + /*
>>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>>> + * exception to guest.
>>>>>> + */
>>>>>> + __u32 exception;
>>>>>> + /*
>>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>>> + * (read, write or both) and software breakpoint.
>>>>>> + */
>>>>>> + __u32 status;
>>>>>> };
>>>>>
>>>>> What does "exception number" mean in a generic API?
>>>>
>>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>>
>>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>>
>>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>>
>> We can pass up the exception type; it just needs more documentation
>> about what exactly you're referring to, and probably some enumeration
>> that says which exception numberspace it is.
>>
>> For booke the exception number should probably be related to the fixed
>> offsets rather than the IVOR number, as IVORs are phased out.
>
> Jan, I would like to get your comment on this one.
>
> Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
>
> If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
Reinjection depends on userspace. It has to check if the debug event was
related to the host debugging the guest or if it was due to a
guest-internal debugging event. That's because the kernel does not track
individual breakpoints, just controls the trapping. So we need a way to
manage the reinjection, and we do this (on x86) by passing the exception
up and then using it for SET_VCPU_EVENTS to reinject it if necessary.
The general logic (reinjection filter in userspace) should be generic
enough, but all the details can, of course, be defined in an
arch-specific manner.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-25 10:38 ` Jan Kiszka
@ 2012-09-25 10:47 ` Alexander Graf
2012-09-25 10:56 ` Jan Kiszka
0 siblings, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-09-25 10:47 UTC (permalink / raw)
To: Jan Kiszka
Cc: Scott Wood, Bhushan Bharat-R65777, Wood Scott-B07421,
kvm-ppc@vger.kernel.org, KVM list
On 25.09.2012, at 12:38, Jan Kiszka wrote:
> On 2012-09-24 16:46, Alexander Graf wrote:
>>
>> On 07.09.2012, at 00:56, Scott Wood wrote:
>>
>>> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Wood Scott-B07421
>>>>> Sent: Thursday, September 06, 2012 4:57 AM
>>>>> To: Bhushan Bharat-R65777
>>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>>>> R65777
>>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>>
>>>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>>>> breakpoint to debug guest.
>>>>>>>
>>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>>>> ---
>>>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>>>> --
>>>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>>>> +++++++++++++++++++++++++++++++-
>>>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>>>
>>>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>>>> @@ -25,6 +25,7 @@
>>>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>>>
>>>>>>> struct kvm_regs {
>>>>>>> __u64 pc;
>>>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>>>> __u64 fpr[32];
>>>>>>> };
>>>>>>>
>>>>>>> +
>>>>>>> +/*
>>>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>>>> + * software breakpoint.
>>>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>>>> + * for KVM_DEBUG_EXIT.
>>>>>>> + */
>>>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>>>> struct kvm_debug_exit_arch {
>>>>>>
>>>>>> That says "arch", but it's not in an arch-specific file.
>>>>>
>>>>> Sigh, I can't read today apparently.
>>>>>
>>>>>>> + __u64 pc;
>>>>>>> + /*
>>>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>>>> + * exception to guest.
>>>>>>> + */
>>>>>>> + __u32 exception;
>>>>>>> + /*
>>>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>>>> + * (read, write or both) and software breakpoint.
>>>>>>> + */
>>>>>>> + __u32 status;
>>>>>>> };
>>>>>>
>>>>>> What does "exception number" mean in a generic API?
>>>>>
>>>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>>>
>>>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>>>
>>>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>>>
>>> We can pass up the exception type; it just needs more documentation
>>> about what exactly you're referring to, and probably some enumeration
>>> that says which exception numberspace it is.
>>>
>>> For booke the exception number should probably be related to the fixed
>>> offsets rather than the IVOR number, as IVORs are phased out.
>>
>> Jan, I would like to get your comment on this one.
>>
>> Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
>>
>> If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
>
> Reinjection depends on userspace. It has to check if the debug event was
> related to the host debugging the guest or if it was due to a
> guest-internal debugging event. That's because the kernel does not track
> individual breakpoints, just controls the trapping. So we need a way to
> manage the reinjection, and we do this (on x86) by passing the exception
> up and then using it for SET_VCPU_EVENTS to reinject it if necessary.
>
> The general logic (reinjection filter in userspace) should be generic
> enough, but all the details can, of course, be defined in an
> arch-specific manner.
Well, we could always just pass a payload to user space that it passes into an ioctl to the kernel to reinject the interrupt. But that would break migratability as this payload wouldn't get stored in env.
But the same thing applies to x86, right? So if just pass a struct kvm_vcpu_events with the debug interrupt as return value, user space can simply use that to reinject it with SET_VCPU_EVENTS.
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-25 10:47 ` Alexander Graf
@ 2012-09-25 10:56 ` Jan Kiszka
2012-09-25 10:58 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Jan Kiszka @ 2012-09-25 10:56 UTC (permalink / raw)
To: Alexander Graf
Cc: Scott Wood, Bhushan Bharat-R65777, Wood Scott-B07421,
kvm-ppc@vger.kernel.org, KVM list
On 2012-09-25 12:47, Alexander Graf wrote:
>
> On 25.09.2012, at 12:38, Jan Kiszka wrote:
>
>> On 2012-09-24 16:46, Alexander Graf wrote:
>>>
>>> On 07.09.2012, at 00:56, Scott Wood wrote:
>>>
>>>> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>>>>
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Wood Scott-B07421
>>>>>> Sent: Thursday, September 06, 2012 4:57 AM
>>>>>> To: Bhushan Bharat-R65777
>>>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>>>>> R65777
>>>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>>>
>>>>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>>>>> breakpoint to debug guest.
>>>>>>>>
>>>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>>>>> ---
>>>>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>>>>> --
>>>>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>>>>> +++++++++++++++++++++++++++++++-
>>>>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>>>>> @@ -25,6 +25,7 @@
>>>>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>>>>
>>>>>>>> struct kvm_regs {
>>>>>>>> __u64 pc;
>>>>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>>>>> __u64 fpr[32];
>>>>>>>> };
>>>>>>>>
>>>>>>>> +
>>>>>>>> +/*
>>>>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>>>>> + * software breakpoint.
>>>>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>>>>> + * for KVM_DEBUG_EXIT.
>>>>>>>> + */
>>>>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>>>>> struct kvm_debug_exit_arch {
>>>>>>>
>>>>>>> That says "arch", but it's not in an arch-specific file.
>>>>>>
>>>>>> Sigh, I can't read today apparently.
>>>>>>
>>>>>>>> + __u64 pc;
>>>>>>>> + /*
>>>>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>>>>> + * exception to guest.
>>>>>>>> + */
>>>>>>>> + __u32 exception;
>>>>>>>> + /*
>>>>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>>>>> + * (read, write or both) and software breakpoint.
>>>>>>>> + */
>>>>>>>> + __u32 status;
>>>>>>>> };
>>>>>>>
>>>>>>> What does "exception number" mean in a generic API?
>>>>>>
>>>>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>>>>
>>>>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>>>>
>>>>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>>>>
>>>> We can pass up the exception type; it just needs more documentation
>>>> about what exactly you're referring to, and probably some enumeration
>>>> that says which exception numberspace it is.
>>>>
>>>> For booke the exception number should probably be related to the fixed
>>>> offsets rather than the IVOR number, as IVORs are phased out.
>>>
>>> Jan, I would like to get your comment on this one.
>>>
>>> Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
>>>
>>> If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
>>
>> Reinjection depends on userspace. It has to check if the debug event was
>> related to the host debugging the guest or if it was due to a
>> guest-internal debugging event. That's because the kernel does not track
>> individual breakpoints, just controls the trapping. So we need a way to
>> manage the reinjection, and we do this (on x86) by passing the exception
>> up and then using it for SET_VCPU_EVENTS to reinject it if necessary.
>>
>> The general logic (reinjection filter in userspace) should be generic
>> enough, but all the details can, of course, be defined in an
>> arch-specific manner.
>
> Well, we could always just pass a payload to user space that it passes into an ioctl to the kernel to reinject the interrupt. But that would break migratability as this payload wouldn't get stored in env.
Right.
>
> But the same thing applies to x86, right? So if just pass a struct kvm_vcpu_events with the debug interrupt as return value, user space can simply use that to reinject it with SET_VCPU_EVENTS.
Sorry, I'm slow today: That's a proposal for booke now?
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-25 10:56 ` Jan Kiszka
@ 2012-09-25 10:58 ` Alexander Graf
2012-09-25 11:06 ` Jan Kiszka
0 siblings, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-09-25 10:58 UTC (permalink / raw)
To: Jan Kiszka
Cc: Scott Wood, Bhushan Bharat-R65777, Wood Scott-B07421,
kvm-ppc@vger.kernel.org, KVM list
On 25.09.2012, at 12:56, Jan Kiszka wrote:
> On 2012-09-25 12:47, Alexander Graf wrote:
>>
>> On 25.09.2012, at 12:38, Jan Kiszka wrote:
>>
>>> On 2012-09-24 16:46, Alexander Graf wrote:
>>>>
>>>> On 07.09.2012, at 00:56, Scott Wood wrote:
>>>>
>>>>> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>>>>>
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Wood Scott-B07421
>>>>>>> Sent: Thursday, September 06, 2012 4:57 AM
>>>>>>> To: Bhushan Bharat-R65777
>>>>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>>>>>> R65777
>>>>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>>>>
>>>>>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>>>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>>>>>> breakpoint to debug guest.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>>>>>> ---
>>>>>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>>>>>> --
>>>>>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>>>>>> +++++++++++++++++++++++++++++++-
>>>>>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>>>>>> @@ -25,6 +25,7 @@
>>>>>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>>>>>
>>>>>>>>> struct kvm_regs {
>>>>>>>>> __u64 pc;
>>>>>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>>>>>> __u64 fpr[32];
>>>>>>>>> };
>>>>>>>>>
>>>>>>>>> +
>>>>>>>>> +/*
>>>>>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>>>>>> + * software breakpoint.
>>>>>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>>>>>> + * for KVM_DEBUG_EXIT.
>>>>>>>>> + */
>>>>>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>>>>>> struct kvm_debug_exit_arch {
>>>>>>>>
>>>>>>>> That says "arch", but it's not in an arch-specific file.
>>>>>>>
>>>>>>> Sigh, I can't read today apparently.
>>>>>>>
>>>>>>>>> + __u64 pc;
>>>>>>>>> + /*
>>>>>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>>>>>> + * exception to guest.
>>>>>>>>> + */
>>>>>>>>> + __u32 exception;
>>>>>>>>> + /*
>>>>>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>>>>>> + * (read, write or both) and software breakpoint.
>>>>>>>>> + */
>>>>>>>>> + __u32 status;
>>>>>>>>> };
>>>>>>>>
>>>>>>>> What does "exception number" mean in a generic API?
>>>>>>>
>>>>>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>>>>>
>>>>>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>>>>>
>>>>>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>>>>>
>>>>> We can pass up the exception type; it just needs more documentation
>>>>> about what exactly you're referring to, and probably some enumeration
>>>>> that says which exception numberspace it is.
>>>>>
>>>>> For booke the exception number should probably be related to the fixed
>>>>> offsets rather than the IVOR number, as IVORs are phased out.
>>>>
>>>> Jan, I would like to get your comment on this one.
>>>>
>>>> Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
>>>>
>>>> If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
>>>
>>> Reinjection depends on userspace. It has to check if the debug event was
>>> related to the host debugging the guest or if it was due to a
>>> guest-internal debugging event. That's because the kernel does not track
>>> individual breakpoints, just controls the trapping. So we need a way to
>>> manage the reinjection, and we do this (on x86) by passing the exception
>>> up and then using it for SET_VCPU_EVENTS to reinject it if necessary.
>>>
>>> The general logic (reinjection filter in userspace) should be generic
>>> enough, but all the details can, of course, be defined in an
>>> arch-specific manner.
>>
>> Well, we could always just pass a payload to user space that it passes into an ioctl to the kernel to reinject the interrupt. But that would break migratability as this payload wouldn't get stored in env.
>
> Right.
>
>>
>> But the same thing applies to x86, right? So if just pass a struct kvm_vcpu_events with the debug interrupt as return value, user space can simply use that to reinject it with SET_VCPU_EVENTS.
>
> Sorry, I'm slow today: That's a proposal for booke now?
Yes, that's a proposal for PPC in general, because we need to be extensible enough to transmit all data that Book3S one day might also want to have.
The thing I was saying is that if we make the payload magical, we need to make debug exits atomic. Otherwise QEMU could try to live migrate away from us and we lose state. I suppose x86 doesn't have this problem because it shoehorns the exception vectors into env?
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-25 10:58 ` Alexander Graf
@ 2012-09-25 11:06 ` Jan Kiszka
2012-09-25 11:10 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Jan Kiszka @ 2012-09-25 11:06 UTC (permalink / raw)
To: Alexander Graf
Cc: Scott Wood, Bhushan Bharat-R65777, Wood Scott-B07421,
kvm-ppc@vger.kernel.org, KVM list
On 2012-09-25 12:58, Alexander Graf wrote:
>
> On 25.09.2012, at 12:56, Jan Kiszka wrote:
>
>> On 2012-09-25 12:47, Alexander Graf wrote:
>>>
>>> On 25.09.2012, at 12:38, Jan Kiszka wrote:
>>>
>>>> On 2012-09-24 16:46, Alexander Graf wrote:
>>>>>
>>>>> On 07.09.2012, at 00:56, Scott Wood wrote:
>>>>>
>>>>>> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>>>>>>
>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: Wood Scott-B07421
>>>>>>>> Sent: Thursday, September 06, 2012 4:57 AM
>>>>>>>> To: Bhushan Bharat-R65777
>>>>>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>>>>>>> R65777
>>>>>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>>>>>
>>>>>>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>>>>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>>>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>>>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>>>>>>> breakpoint to debug guest.
>>>>>>>>>>
>>>>>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>>>>>>> ---
>>>>>>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>>>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>>>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>>>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>>>>>>> --
>>>>>>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>>>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>>>>>>> +++++++++++++++++++++++++++++++-
>>>>>>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>>>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>>>>>>
>>>>>>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>>>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>>>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>>>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>>>>>>> @@ -25,6 +25,7 @@
>>>>>>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>>>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>>>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>>>>>>
>>>>>>>>>> struct kvm_regs {
>>>>>>>>>> __u64 pc;
>>>>>>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>>>>>>> __u64 fpr[32];
>>>>>>>>>> };
>>>>>>>>>>
>>>>>>>>>> +
>>>>>>>>>> +/*
>>>>>>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>>>>>>> + * software breakpoint.
>>>>>>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>>>>>>> + * for KVM_DEBUG_EXIT.
>>>>>>>>>> + */
>>>>>>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>>>>>>> struct kvm_debug_exit_arch {
>>>>>>>>>
>>>>>>>>> That says "arch", but it's not in an arch-specific file.
>>>>>>>>
>>>>>>>> Sigh, I can't read today apparently.
>>>>>>>>
>>>>>>>>>> + __u64 pc;
>>>>>>>>>> + /*
>>>>>>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>>>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>>>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>>>>>>> + * exception to guest.
>>>>>>>>>> + */
>>>>>>>>>> + __u32 exception;
>>>>>>>>>> + /*
>>>>>>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>>>>>>> + * (read, write or both) and software breakpoint.
>>>>>>>>>> + */
>>>>>>>>>> + __u32 status;
>>>>>>>>>> };
>>>>>>>>>
>>>>>>>>> What does "exception number" mean in a generic API?
>>>>>>>>
>>>>>>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>>>>>>
>>>>>>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>>>>>>
>>>>>>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>>>>>>
>>>>>> We can pass up the exception type; it just needs more documentation
>>>>>> about what exactly you're referring to, and probably some enumeration
>>>>>> that says which exception numberspace it is.
>>>>>>
>>>>>> For booke the exception number should probably be related to the fixed
>>>>>> offsets rather than the IVOR number, as IVORs are phased out.
>>>>>
>>>>> Jan, I would like to get your comment on this one.
>>>>>
>>>>> Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
>>>>>
>>>>> If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
>>>>
>>>> Reinjection depends on userspace. It has to check if the debug event was
>>>> related to the host debugging the guest or if it was due to a
>>>> guest-internal debugging event. That's because the kernel does not track
>>>> individual breakpoints, just controls the trapping. So we need a way to
>>>> manage the reinjection, and we do this (on x86) by passing the exception
>>>> up and then using it for SET_VCPU_EVENTS to reinject it if necessary.
>>>>
>>>> The general logic (reinjection filter in userspace) should be generic
>>>> enough, but all the details can, of course, be defined in an
>>>> arch-specific manner.
>>>
>>> Well, we could always just pass a payload to user space that it passes into an ioctl to the kernel to reinject the interrupt. But that would break migratability as this payload wouldn't get stored in env.
>>
>> Right.
>>
>>>
>>> But the same thing applies to x86, right? So if just pass a struct kvm_vcpu_events with the debug interrupt as return value, user space can simply use that to reinject it with SET_VCPU_EVENTS.
>>
>> Sorry, I'm slow today: That's a proposal for booke now?
>
> Yes, that's a proposal for PPC in general, because we need to be extensible enough to transmit all data that Book3S one day might also want to have.
>
> The thing I was saying is that if we make the payload magical, we need to make debug exits atomic. Otherwise QEMU could try to live migrate away from us and we lose state. I suppose x86 doesn't have this problem because it shoehorns the exception vectors into env?
It's no problem on x86 as our VCPU state can encode pending (debug)
exceptions, so we can store them also for migration. If PPC doesn't
allow to read/write such kind of state from/to the kernel, you can't
easily do the same. If debugging would be the only reason to do this, it
might be ok to declare that state atomic.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-25 11:06 ` Jan Kiszka
@ 2012-09-25 11:10 ` Alexander Graf
0 siblings, 0 replies; 32+ messages in thread
From: Alexander Graf @ 2012-09-25 11:10 UTC (permalink / raw)
To: Jan Kiszka
Cc: Scott Wood, Bhushan Bharat-R65777, Wood Scott-B07421,
kvm-ppc@vger.kernel.org, KVM list
On 25.09.2012, at 13:06, Jan Kiszka wrote:
> On 2012-09-25 12:58, Alexander Graf wrote:
>>
>> On 25.09.2012, at 12:56, Jan Kiszka wrote:
>>
>>> On 2012-09-25 12:47, Alexander Graf wrote:
>>>>
>>>> On 25.09.2012, at 12:38, Jan Kiszka wrote:
>>>>
>>>>> On 2012-09-24 16:46, Alexander Graf wrote:
>>>>>>
>>>>>> On 07.09.2012, at 00:56, Scott Wood wrote:
>>>>>>
>>>>>>> On 09/06/2012 09:56 AM, Bhushan Bharat-R65777 wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>> -----Original Message-----
>>>>>>>>> From: Wood Scott-B07421
>>>>>>>>> Sent: Thursday, September 06, 2012 4:57 AM
>>>>>>>>> To: Bhushan Bharat-R65777
>>>>>>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; agraf@suse.de; Bhushan Bharat-
>>>>>>>>> R65777
>>>>>>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>>>>>>
>>>>>>>>> On 09/05/2012 06:23 PM, Scott Wood wrote:
>>>>>>>>>> On 08/21/2012 08:52 AM, Bharat Bhushan wrote:
>>>>>>>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>>>>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>>>>>>>> breakpoint to debug guest.
>>>>>>>>>>>
>>>>>>>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>>>>>>>> ---
>>>>>>>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>>>>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>>>>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>>>>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>>>>>>>>> --
>>>>>>>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>>>>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>>>>>>>>> +++++++++++++++++++++++++++++++-
>>>>>>>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>>>>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>>>>>>>
>>>>>>>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>>>>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>>>>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>>>>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>>>>>>>> @@ -25,6 +25,7 @@
>>>>>>>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>>>>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>>>>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>>>>>>>
>>>>>>>>>>> struct kvm_regs {
>>>>>>>>>>> __u64 pc;
>>>>>>>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>>>>>>>> __u64 fpr[32];
>>>>>>>>>>> };
>>>>>>>>>>>
>>>>>>>>>>> +
>>>>>>>>>>> +/*
>>>>>>>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>>>>>>>> + * software breakpoint.
>>>>>>>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>>>>>>>> + * for KVM_DEBUG_EXIT.
>>>>>>>>>>> + */
>>>>>>>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>>>>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>>>>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>>>>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>>>>>>>> struct kvm_debug_exit_arch {
>>>>>>>>>>
>>>>>>>>>> That says "arch", but it's not in an arch-specific file.
>>>>>>>>>
>>>>>>>>> Sigh, I can't read today apparently.
>>>>>>>>>
>>>>>>>>>>> + __u64 pc;
>>>>>>>>>>> + /*
>>>>>>>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>>>>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>>>>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>>>>>>>> + * exception to guest.
>>>>>>>>>>> + */
>>>>>>>>>>> + __u32 exception;
>>>>>>>>>>> + /*
>>>>>>>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>>>>>>>> + * (read, write or both) and software breakpoint.
>>>>>>>>>>> + */
>>>>>>>>>>> + __u32 status;
>>>>>>>>>>> };
>>>>>>>>>>
>>>>>>>>>> What does "exception number" mean in a generic API?
>>>>>>>>>
>>>>>>>>> Still, "exception number" is not a well-defined concept powerpc-wide.
>>>>>>>>
>>>>>>>> Just for background why we added is that, on x86 this exception number is used to inject the exception to guest if QEMU is not able to handle the debug exception.
>>>>>>>>
>>>>>>>> Should we just through a print with clearing the exception condition? Or something else you would like to suggest?
>>>>>>>
>>>>>>> We can pass up the exception type; it just needs more documentation
>>>>>>> about what exactly you're referring to, and probably some enumeration
>>>>>>> that says which exception numberspace it is.
>>>>>>>
>>>>>>> For booke the exception number should probably be related to the fixed
>>>>>>> offsets rather than the IVOR number, as IVORs are phased out.
>>>>>>
>>>>>> Jan, I would like to get your comment on this one.
>>>>>>
>>>>>> Since we don't have standardized exception vectors like x86 does, we need to convert things between different semantics in user space if we want to make use of the exception type. Do we actually need to know about it in user space or do we only need to store it in case we get a migration at that point?
>>>>>>
>>>>>> If it's the latter, can we maybe keep the reinjection logic internal to KVM and make DEBUG exits non-migratable similar to how we already handle MMIO/PIO exits today?
>>>>>
>>>>> Reinjection depends on userspace. It has to check if the debug event was
>>>>> related to the host debugging the guest or if it was due to a
>>>>> guest-internal debugging event. That's because the kernel does not track
>>>>> individual breakpoints, just controls the trapping. So we need a way to
>>>>> manage the reinjection, and we do this (on x86) by passing the exception
>>>>> up and then using it for SET_VCPU_EVENTS to reinject it if necessary.
>>>>>
>>>>> The general logic (reinjection filter in userspace) should be generic
>>>>> enough, but all the details can, of course, be defined in an
>>>>> arch-specific manner.
>>>>
>>>> Well, we could always just pass a payload to user space that it passes into an ioctl to the kernel to reinject the interrupt. But that would break migratability as this payload wouldn't get stored in env.
>>>
>>> Right.
>>>
>>>>
>>>> But the same thing applies to x86, right? So if just pass a struct kvm_vcpu_events with the debug interrupt as return value, user space can simply use that to reinject it with SET_VCPU_EVENTS.
>>>
>>> Sorry, I'm slow today: That's a proposal for booke now?
>>
>> Yes, that's a proposal for PPC in general, because we need to be extensible enough to transmit all data that Book3S one day might also want to have.
>>
>> The thing I was saying is that if we make the payload magical, we need to make debug exits atomic. Otherwise QEMU could try to live migrate away from us and we lose state. I suppose x86 doesn't have this problem because it shoehorns the exception vectors into env?
>
> It's no problem on x86 as our VCPU state can encode pending (debug)
> exceptions, so we can store them also for migration. If PPC doesn't
> allow to read/write such kind of state from/to the kernel, you can't
> easily do the same. If debugging would be the only reason to do this, it
> might be ok to declare that state atomic.
Well, we do have such state as well. But it's quite different depending on the board, so it'd be a bunch of code that I'd rather not have around if it doesn't buy us too much.
Though I guess it's the cleanest way to do it. Sigh.
So we pass a struct kvm_vcpu_events up with the debug interrupt. That way a different user space can simply reinject it if it wants to. For QEMU, we would interpret that thing, shove all the fields into their respective env counterparts with the QEMU internal exception vector definitions and do the reverse in kvm_put_vcpu_events.
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct
2012-09-24 16:27 ` Alexander Graf
@ 2012-10-04 6:50 ` Bhushan Bharat-R65777
0 siblings, 0 replies; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-10-04 6:50 UTC (permalink / raw)
To: Alexander Graf; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
> -----Original Message-----
> From: Alexander Graf [mailto:agraf@suse.de]
> Sent: Monday, September 24, 2012 9:58 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct
>
>
> On 21.08.2012, at 15:51, Bharat Bhushan wrote:
>
> > Like other places, use thread_struct to get vcpu reference.
>
> Please remove the definition of SPRN_SPRG_R/WVCPU as well.
Ok
Thanks
-Bharat
>
>
> Alex
>
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> > ---
> > arch/powerpc/kernel/asm-offsets.c | 2 +-
> > arch/powerpc/kvm/booke_interrupts.S | 6 ++----
> > 2 files changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/asm-offsets.c
> > b/arch/powerpc/kernel/asm-offsets.c
> > index 85b05c4..fbb999c 100644
> > --- a/arch/powerpc/kernel/asm-offsets.c
> > +++ b/arch/powerpc/kernel/asm-offsets.c
> > @@ -116,7 +116,7 @@ int main(void)
> > #ifdef CONFIG_KVM_BOOK3S_32_HANDLER
> > DEFINE(THREAD_KVM_SVCPU, offsetof(struct thread_struct,
> > kvm_shadow_vcpu)); #endif -#ifdef CONFIG_KVM_BOOKE_HV
> > +#if defined(CONFIG_KVM) && defined(CONFIG_BOOKE)
> > DEFINE(THREAD_KVM_VCPU, offsetof(struct thread_struct, kvm_vcpu));
> > #endif
> >
> > diff --git a/arch/powerpc/kvm/booke_interrupts.S
> > b/arch/powerpc/kvm/booke_interrupts.S
> > index bb46b32..ca16d57 100644
> > --- a/arch/powerpc/kvm/booke_interrupts.S
> > +++ b/arch/powerpc/kvm/booke_interrupts.S
> > @@ -56,7 +56,8 @@
> > _GLOBAL(kvmppc_handler_\ivor_nr)
> > /* Get pointer to vcpu and record exit number. */
> > mtspr \scratch , r4
> > - mfspr r4, SPRN_SPRG_RVCPU
> > + mfspr r4, SPRN_SPRG_THREAD
> > + lwz r4, THREAD_KVM_VCPU(r4)
> > stw r3, VCPU_GPR(R3)(r4)
> > stw r5, VCPU_GPR(R5)(r4)
> > stw r6, VCPU_GPR(R6)(r4)
> > @@ -402,9 +403,6 @@ lightweight_exit:
> > lwz r8, kvmppc_booke_handlers@l(r8)
> > mtspr SPRN_IVPR, r8
> >
> > - /* Save vcpu pointer for the exception handlers. */
> > - mtspr SPRN_SPRG_WVCPU, r4
> > -
> > lwz r5, VCPU_SHARED(r4)
> >
> > /* Can't switch the stack pointer until after IVPR is switched,
> > --
> > 1.7.0.4
> >
> >
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
2012-09-24 15:38 ` Alexander Graf
@ 2012-10-04 7:14 ` Bhushan Bharat-R65777
2012-12-17 16:56 ` Alexander Graf
2012-10-04 7:37 ` Bhushan Bharat-R65777
1 sibling, 1 reply; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-10-04 7:14 UTC (permalink / raw)
To: Alexander Graf; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
> -----Original Message-----
> From: Alexander Graf [mailto:agraf@suse.de]
> Sent: Monday, September 24, 2012 9:09 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
>
>
> On 21.08.2012, at 15:51, Bharat Bhushan wrote:
>
> > This patch defines the interface parameter for KVM_SET_GUEST_DEBUG
> > ioctl support. Follow up patches will use this for setting up hardware
> > breakpoints, watchpoints and software breakpoints.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> > ---
> > arch/powerpc/include/asm/kvm.h | 33 +++++++++++++++++++++++++++++++++
> > arch/powerpc/kvm/book3s.c | 6 ++++++
> > arch/powerpc/kvm/booke.c | 6 ++++++
> > arch/powerpc/kvm/powerpc.c | 6 ------
> > 4 files changed, 45 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/kvm.h
> > b/arch/powerpc/include/asm/kvm.h index 3c14202..61b197e 100644
> > --- a/arch/powerpc/include/asm/kvm.h
> > +++ b/arch/powerpc/include/asm/kvm.h
> > @@ -269,8 +269,41 @@ struct kvm_debug_exit_arch {
> >
> > /* for KVM_SET_GUEST_DEBUG */
> > struct kvm_guest_debug_arch {
> > + struct {
> > + /* H/W breakpoint/watchpoint address */
> > + __u64 addr;
> > + /*
> > + * Type denotes h/w breakpoint, read watchpoint, write
> > + * watchpoint or watchpoint (both read and write).
> > + */
> > +#define KVMPPC_DEBUG_NOTYPE 0x0
> > +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> > +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> > +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> > + __u32 type;
> > + __u32 pad1;
>
> Why the padding?
Not sure why, I will remove this.
>
> > + __u64 pad2;
> > + } bp[16];
>
> Why 16?
I think for now 6 (4 iac + 2 dac) is sufficient for BOOKE. We kept 16 to have some room for future and other platforms.
Thanks
-Bharat
>
> > };
> >
> > +/* Debug related defines */
> > +/*
> > + * kvm_guest_debug->control is a 32 bit field. The lower 16 bits are
> > +generic
> > + * and upper 16 bits are architecture specific. Architecture specific
> > +defines
> > + * that ioctl is for setting hardware breakpoint or software breakpoint.
> > + */
> > +#define KVM_GUESTDBG_USE_SW_BP 0x00010000
> > +#define KVM_GUESTDBG_USE_HW_BP 0x00020000
> > +
> > +/* When setting software breakpoint, Change the software breakpoint
> > + * instruction to special trap instruction and set
> > +KVM_GUESTDBG_USE_SW_BP
> > + * flag in kvm_guest_debug->control. KVM does keep track of software
> > + * breakpoints. So when KVM_GUESTDBG_USE_SW_BP flag is set and
> > +special trap
> > + * instruction is executed by guest then exit to userspace.
> > + * NOTE: A Nice interface can be added to get the special trap instruction.
> > + */
> > +#define KVMPPC_INST_GUEST_GDB 0x7C00021C /* ehpriv OC=0 */
>
> This definitely has to be passed to user space (which writes that instruction
> into guest phys memory). Other PPC subarchs will use different instructions.
> Just model it as a read-only ONE_REG.
>
>
> Alex
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
2012-09-24 15:38 ` Alexander Graf
2012-10-04 7:14 ` Bhushan Bharat-R65777
@ 2012-10-04 7:37 ` Bhushan Bharat-R65777
1 sibling, 0 replies; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-10-04 7:37 UTC (permalink / raw)
To: Alexander Graf; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
> -----Original Message-----
> From: Alexander Graf [mailto:agraf@suse.de]
> Sent: Monday, September 24, 2012 9:09 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
>
>
> On 21.08.2012, at 15:51, Bharat Bhushan wrote:
>
> > This patch defines the interface parameter for KVM_SET_GUEST_DEBUG
> > ioctl support. Follow up patches will use this for setting up hardware
> > breakpoints, watchpoints and software breakpoints.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> > ---
> > arch/powerpc/include/asm/kvm.h | 33 +++++++++++++++++++++++++++++++++
> > arch/powerpc/kvm/book3s.c | 6 ++++++
> > arch/powerpc/kvm/booke.c | 6 ++++++
> > arch/powerpc/kvm/powerpc.c | 6 ------
> > 4 files changed, 45 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/kvm.h
> > b/arch/powerpc/include/asm/kvm.h index 3c14202..61b197e 100644
> > --- a/arch/powerpc/include/asm/kvm.h
> > +++ b/arch/powerpc/include/asm/kvm.h
> > @@ -269,8 +269,41 @@ struct kvm_debug_exit_arch {
> >
> > /* for KVM_SET_GUEST_DEBUG */
> > struct kvm_guest_debug_arch {
> > + struct {
> > + /* H/W breakpoint/watchpoint address */
> > + __u64 addr;
> > + /*
> > + * Type denotes h/w breakpoint, read watchpoint, write
> > + * watchpoint or watchpoint (both read and write).
> > + */
> > +#define KVMPPC_DEBUG_NOTYPE 0x0
> > +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> > +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> > +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> > + __u32 type;
> > + __u32 pad1;
>
> Why the padding?
>
> > + __u64 pad2;
> > + } bp[16];
>
> Why 16?
>
> > };
> >
> > +/* Debug related defines */
> > +/*
> > + * kvm_guest_debug->control is a 32 bit field. The lower 16 bits are
> > +generic
> > + * and upper 16 bits are architecture specific. Architecture specific
> > +defines
> > + * that ioctl is for setting hardware breakpoint or software breakpoint.
> > + */
> > +#define KVM_GUESTDBG_USE_SW_BP 0x00010000
> > +#define KVM_GUESTDBG_USE_HW_BP 0x00020000
> > +
> > +/* When setting software breakpoint, Change the software breakpoint
> > + * instruction to special trap instruction and set
> > +KVM_GUESTDBG_USE_SW_BP
> > + * flag in kvm_guest_debug->control. KVM does keep track of software
> > + * breakpoints. So when KVM_GUESTDBG_USE_SW_BP flag is set and
> > +special trap
> > + * instruction is executed by guest then exit to userspace.
> > + * NOTE: A Nice interface can be added to get the special trap instruction.
> > + */
> > +#define KVMPPC_INST_GUEST_GDB 0x7C00021C /* ehpriv OC=0 */
>
> This definitely has to be passed to user space (which writes that instruction
> into guest phys memory). Other PPC subarchs will use different instructions.
> Just model it as a read-only ONE_REG.
Ok.
Thanks
-Bharat
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-09-24 16:20 ` Alexander Graf
@ 2012-10-04 11:06 ` Bhushan Bharat-R65777
2012-10-04 11:25 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-10-04 11:06 UTC (permalink / raw)
To: Alexander Graf; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
> -----Original Message-----
> From: Alexander Graf [mailto:agraf@suse.de]
> Sent: Monday, September 24, 2012 9:50 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>
>
> On 21.08.2012, at 15:52, Bharat Bhushan wrote:
>
> > This patch adds the debug stub support on booke/bookehv.
> > Now QEMU debug stub can use hw breakpoint, watchpoint and
> > software breakpoint to debug guest.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> > ---
> > arch/powerpc/include/asm/kvm.h | 29 ++++++-
> > arch/powerpc/include/asm/kvm_host.h | 5 +
> > arch/powerpc/kernel/asm-offsets.c | 26 ++++++
> > arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++----
> > arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
> > arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++++++++++-
> > arch/powerpc/kvm/e500mc.c | 3 +-
> > 7 files changed, 435 insertions(+), 23 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
> > index 61b197e..53479ea 100644
> > --- a/arch/powerpc/include/asm/kvm.h
> > +++ b/arch/powerpc/include/asm/kvm.h
> > @@ -25,6 +25,7 @@
> > /* Select powerpc specific features in <linux/kvm.h> */
> > #define __KVM_HAVE_SPAPR_TCE
> > #define __KVM_HAVE_PPC_SMT
> > +#define __KVM_HAVE_GUEST_DEBUG
> >
> > struct kvm_regs {
> > __u64 pc;
> > @@ -264,7 +265,31 @@ struct kvm_fpu {
> > __u64 fpr[32];
> > };
> >
> > +
> > +/*
> > + * Defines for h/w breakpoint, watchpoint (read, write or both) and
> > + * software breakpoint.
> > + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
> > + * for KVM_DEBUG_EXIT.
> > + */
> > +#define KVMPPC_DEBUG_NONE 0x0
> > +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> > +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> > +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> > struct kvm_debug_exit_arch {
> > + __u64 pc;
> > + /*
> > + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
> > + * exit is not handled (say not h/w breakpoint or software breakpoint
> > + * set for this address) by qemu then it is supposed to inject this
> > + * exception to guest.
> > + */
> > + __u32 exception;
> > + /*
> > + * exiting to userspace because of h/w breakpoint, watchpoint
> > + * (read, write or both) and software breakpoint.
> > + */
> > + __u32 status;
> > };
> >
> > /* for KVM_SET_GUEST_DEBUG */
> > @@ -276,10 +301,6 @@ struct kvm_guest_debug_arch {
> > * Type denotes h/w breakpoint, read watchpoint, write
> > * watchpoint or watchpoint (both read and write).
> > */
> > -#define KVMPPC_DEBUG_NOTYPE 0x0
> > -#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> > -#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> > -#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> > __u32 type;
> > __u32 pad1;
> > __u64 pad2;
> > diff --git a/arch/powerpc/include/asm/kvm_host.h
> b/arch/powerpc/include/asm/kvm_host.h
> > index c7219c1..3ba465a 100644
> > --- a/arch/powerpc/include/asm/kvm_host.h
> > +++ b/arch/powerpc/include/asm/kvm_host.h
> > @@ -496,7 +496,12 @@ struct kvm_vcpu_arch {
> > u32 mmucfg;
> > u32 epr;
> > u32 crit_save;
> > + /* guest debug registers*/
> > struct kvmppc_booke_debug_reg dbg_reg;
> > + /* shadow debug registers */
> > + struct kvmppc_booke_debug_reg shadow_dbg_reg;
> > + /* host debug registers*/
> > + struct kvmppc_booke_debug_reg host_dbg_reg;
> > #endif
> > gpa_t paddr_accessed;
> > gva_t vaddr_accessed;
> > diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-
> offsets.c
> > index 555448e..6987821 100644
> > --- a/arch/powerpc/kernel/asm-offsets.c
> > +++ b/arch/powerpc/kernel/asm-offsets.c
> > @@ -564,6 +564,32 @@ int main(void)
> > DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
> > DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
> > DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
> > + DEFINE(VCPU_DBSR, offsetof(struct kvm_vcpu, arch.dbsr));
> > + DEFINE(VCPU_SHADOW_DBG, offsetof(struct kvm_vcpu, arch.shadow_dbg_reg));
> > + DEFINE(VCPU_HOST_DBG, offsetof(struct kvm_vcpu, arch.host_dbg_reg));
> > + DEFINE(KVMPPC_DBG_DBCR0, offsetof(struct kvmppc_booke_debug_reg,
> > + dbcr0));
> > + DEFINE(KVMPPC_DBG_DBCR1, offsetof(struct kvmppc_booke_debug_reg,
> > + dbcr1));
> > + DEFINE(KVMPPC_DBG_DBCR2, offsetof(struct kvmppc_booke_debug_reg,
> > + dbcr2));
> > +#ifdef CONFIG_KVM_E500MC
> > + DEFINE(KVMPPC_DBG_DBCR4, offsetof(struct kvmppc_booke_debug_reg,
> > + dbcr4));
> > +#endif
> > + DEFINE(KVMPPC_DBG_IAC1, offsetof(struct kvmppc_booke_debug_reg,
> > + iac[0]));
> > + DEFINE(KVMPPC_DBG_IAC2, offsetof(struct kvmppc_booke_debug_reg,
> > + iac[1]));
> > + DEFINE(KVMPPC_DBG_IAC3, offsetof(struct kvmppc_booke_debug_reg,
> > + iac[2]));
> > + DEFINE(KVMPPC_DBG_IAC4, offsetof(struct kvmppc_booke_debug_reg,
> > + iac[3]));
> > + DEFINE(KVMPPC_DBG_DAC1, offsetof(struct kvmppc_booke_debug_reg,
> > + dac[0]));
> > + DEFINE(KVMPPC_DBG_DAC2, offsetof(struct kvmppc_booke_debug_reg,
> > + dac[1]));
> > + DEFINE(VCPU_GUEST_DEBUG, offsetof(struct kvm_vcpu, guest_debug));
> > #endif /* CONFIG_PPC_BOOK3S */
> > #endif /* CONFIG_KVM */
> >
> > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> > index dd0e5b8..4d82e34 100644
> > --- a/arch/powerpc/kvm/booke.c
> > +++ b/arch/powerpc/kvm/booke.c
> > @@ -132,6 +132,9 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)
> >
> > #ifdef CONFIG_KVM_BOOKE_HV
> > new_msr |= MSR_GS;
> > +
> > + if (vcpu->guest_debug)
> > + new_msr |= MSR_DE;
> > #endif
> >
> > vcpu->arch.shared->msr = new_msr;
> > @@ -667,10 +670,21 @@ out:
> > return ret;
> > }
> >
> > -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
> > +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> > + int exit_nr)
> > {
> > enum emulation_result er;
> >
> > + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
> > + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
>
> This belongs into the normal emulation code path, behind the same switch() that
> everything else goes through.
I am not sure I understood correctly. Below is the reason why I placed this code here.
Instruction where software breakpoint is to be set is replaced by "ehpriv" instruction. On e500v2, this is not a valid instruction can causes program interrupt. On e500mc, "ehpriv" is a valid instruction. Both the exit path calls emulation_exit(), so we have placed the code in this function.
Do you want this code to be moved in program interrupt exit path for e500v2 and BOOKE_INTERRUPT_HV_PRIV for e500mc?
>
> > + run->exit_reason = KVM_EXIT_DEBUG;
> > + run->debug.arch.pc = vcpu->arch.pc;
> > + run->debug.arch.exception = exit_nr;
> > + run->debug.arch.status = 0;
> > + kvmppc_account_exit(vcpu, DEBUG_EXITS);
> > + return RESUME_HOST;
> > + }
> > +
> > er = kvmppc_emulate_instruction(run, vcpu);
> > switch (er) {
> > case EMULATE_DONE:
> > @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run *run, struct
> kvm_vcpu *vcpu)
> > default:
> > BUG();
> > }
> > +
> > + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
> > + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
>
> I don't understand how this is supposed to work. When we enable singlestep, why
> would we end up in emulation_exit()?
When singlestep is enabled then we set DBCR0[ICMP] and the debug handler should be able to handle this. I think you are right.
>
> > + run->exit_reason = KVM_EXIT_DEBUG;
> > + return RESUME_HOST;
> > + }
> > +}
> > +
> > +static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu *vcpu)
> > +{
> > + u32 dbsr;
> > +
> > +#ifndef CONFIG_KVM_BOOKE_HV
> > + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
> > + vcpu->arch.pc = mfspr(SPRN_DSRR0);
> > + else
> > + vcpu->arch.pc = mfspr(SPRN_CSRR0);
> > +#endif
>
> Why doesn't this get handled in the asm code that recovers from the respective
> exceptions?
Yes. I will remove this.
>
> > + dbsr = vcpu->arch.dbsr;
> > +
> > + run->debug.arch.pc = vcpu->arch.pc;
> > + run->debug.arch.status = 0;
> > + vcpu->arch.dbsr = 0;
> > +
> > + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
> > + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
> > + } else {
> > + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
> > + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
> > + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
> > + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
> > + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
> > + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
> > + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
> > + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
> > + }
>
> Mind to explain the guest register sharing mechanism you are envisioning? Which
> registers are used by the guest? Which are used by the host? Who decides what
> gets used by whom?
struct kvm_vcpu_arch {
.
.
/* guest debug registers*/
struct kvmppc_booke_debug_reg dbg_reg;
/* shadow debug registers */
struct kvmppc_booke_debug_reg shadow_dbg_reg;
/* host debug registers*/
struct kvmppc_booke_debug_reg host_dbg_reg;
.
.
}
dbg_reg: contains the values written by guest.
shadow_dbg_reg: This contains the actual values to be written on behalf of guest/qemu.
host_dbg_reg: the debug register value of host (needed for store/retore purpose).
According to current design both, the qemu debug stub and guest, cannot share the debug resources. QEMU debug stub is given priority.
But host and guest can share all debug registers and host cannot debug guest if it is using the debug resource (which probably does not look like a good case).
>
> > +
> > + return RESUME_HOST;
> > }
> >
> > static void kvmppc_fill_pt_regs(struct pt_regs *regs)
> > @@ -843,7 +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
> kvm_vcpu *vcpu,
> > break;
> >
> > case BOOKE_INTERRUPT_HV_PRIV:
> > - r = emulation_exit(run, vcpu);
> > + r = emulation_exit(run, vcpu, exit_nr);
> > break;
> >
> > case BOOKE_INTERRUPT_PROGRAM:
> > @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
> kvm_vcpu *vcpu,
> > break;
> > }
> >
> > - r = emulation_exit(run, vcpu);
> > + r = emulation_exit(run, vcpu, exit_nr);
> > break;
> >
> > case BOOKE_INTERRUPT_FP_UNAVAIL:
> > @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
> kvm_vcpu *vcpu,
> > }
> >
> > case BOOKE_INTERRUPT_DEBUG: {
> > - u32 dbsr;
> > -
> > - vcpu->arch.pc = mfspr(SPRN_CSRR0);
> > -
> > - /* clear IAC events in DBSR register */
> > - dbsr = mfspr(SPRN_DBSR);
> > - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
> > - mtspr(SPRN_DBSR, dbsr);
> > -
> > - run->exit_reason = KVM_EXIT_DEBUG;
> > + r = kvmppc_handle_debug(run, vcpu);
> > + if (r == RESUME_HOST) {
> > + run->debug.arch.exception = exit_nr;
> > + run->exit_reason = KVM_EXIT_DEBUG;
> > + }
> > kvmppc_account_exit(vcpu, DEBUG_EXITS);
> > - r = RESUME_HOST;
> > break;
> > }
> >
> > @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,
> struct kvm_one_reg *reg)
> > return r;
> > }
> >
> > +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
> > +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
> > +
> > int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
> > struct kvm_guest_debug *dbg)
> > {
> > - return -EINVAL;
> > +
> > + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
> > + /* Clear All debug events */
> > + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> > + vcpu->guest_debug = 0;
> > + return 0;
> > + }
> > +
> > + vcpu->guest_debug = dbg->control;
> > + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> > +
> > + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
> > + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
> > +
> > + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
> > + struct kvmppc_booke_debug_reg *gdbgr =
> > + &(vcpu->arch.shadow_dbg_reg);
> > + int n, b = 0, w = 0;
> > + const u32 bp_code[] = {
> > + DBCR0_IAC1 | DBCR0_IDM,
> > + DBCR0_IAC2 | DBCR0_IDM,
> > + DBCR0_IAC3 | DBCR0_IDM,
> > + DBCR0_IAC4 | DBCR0_IDM
> > + };
> > + const u32 wp_code[] = {
> > + DBCR0_DAC1W | DBCR0_IDM,
> > + DBCR0_DAC2W | DBCR0_IDM,
> > + DBCR0_DAC1R | DBCR0_IDM,
> > + DBCR0_DAC2R | DBCR0_IDM
> > + };
> > +
> > +#ifndef CONFIG_KVM_BOOKE_HV
> > + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
> > + DBCR1_IAC3US | DBCR1_IAC4US;
> > + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
> > +#else
> > + gdbgr->dbcr1 = 0;
> > + gdbgr->dbcr2 = 0;
> > +#endif
> > +
> > + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
> > + u32 type = dbg->arch.bp[n].type;
> > +
> > + if (!type)
> > + break;
> > +
> > + if (type & (KVMPPC_DEBUG_WATCH_READ |
> > + KVMPPC_DEBUG_WATCH_WRITE)) {
> > + if (w < WP_NUM) {
> > + if (type & KVMPPC_DEBUG_WATCH_READ)
> > + gdbgr->dbcr0 |= wp_code[w + 2];
> > + if (type & KVMPPC_DEBUG_WATCH_WRITE)
> > + gdbgr->dbcr0 |= wp_code[w];
> > + gdbgr->dac[w] = dbg->arch.bp[n].addr;
> > + w++;
> > + }
> > + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
> > + if (b < BP_NUM) {
> > + gdbgr->dbcr0 |= bp_code[b];
> > + gdbgr->iac[b] = dbg->arch.bp[n].addr;
> > + b++;
> > + }
> > + }
> > + }
> > + }
> > + return 0;
> > }
> >
> > int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
> > diff --git a/arch/powerpc/kvm/booke_interrupts.S
> b/arch/powerpc/kvm/booke_interrupts.S
> > index dd9c5d4..2202936 100644
> > --- a/arch/powerpc/kvm/booke_interrupts.S
> > +++ b/arch/powerpc/kvm/booke_interrupts.S
> > @@ -39,6 +39,8 @@
> > #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4)
> > #define HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
> > #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
> > +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
> > + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
> >
> > #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
> > (1<<BOOKE_INTERRUPT_DTLB_MISS) | \
> > @@ -52,6 +54,8 @@
> > (1<<BOOKE_INTERRUPT_PROGRAM) | \
> > (1<<BOOKE_INTERRUPT_DTLB_MISS))
> >
> > +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
> > +
> > .macro __KVM_HANDLER ivor_nr scratch srr0
> > stw r3, VCPU_GPR(R3)(r4)
> > stw r5, VCPU_GPR(R5)(r4)
> > @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
> > stw r9, VCPU_FAULT_ESR(r4)
> > ..skip_esr:
> >
> > + addi r7, r4, VCPU_HOST_DBG
> > + mfspr r9, SPRN_DBCR0
> > + lwz r8, KVMPPC_DBG_DBCR0(r7)
> > + andis. r9, r9, DBCR0_AC_BITS@h
> > + beq skip_load_host_debug
> > + li r9, 0
> > + mtspr SPRN_DBCR0, r9 /* disable all debug event */
> > + lwz r9, KVMPPC_DBG_DBCR1(r7)
> > + mtspr SPRN_DBCR1, r9
> > + lwz r9, KVMPPC_DBG_DBCR2(r7)
> > + mtspr SPRN_DBCR2, r9
> > + lwz r9, KVMPPC_DBG_IAC1+4(r7)
> > + mtspr SPRN_IAC1, r9
> > + lwz r9, KVMPPC_DBG_IAC2+4(r7)
> > + mtspr SPRN_IAC2, r9
> > +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
> > + lwz r9, KVMPPC_DBG_IAC3+4(r7)
> > + mtspr SPRN_IAC3, r9
> > + lwz r9, KVMPPC_DBG_IAC4+4(r7)
> > + mtspr SPRN_IAC4, r9
> > +#endif
> > + lwz r9, KVMPPC_DBG_DAC1+4(r7)
> > + mtspr SPRN_DAC1, r9
> > + lwz r9, KVMPPC_DBG_DAC2+4(r7)
>
> Yikes. Please move this into a struct, similar to how the MSR save/restore
> happens on x86.
>
> Also, these are 64-bit loads and stores, no?
Ok, you mean PPC_LD/STD?
>
> > + mtspr SPRN_DAC2, r9
> > +skip_load_host_debug:
> > + /* Clear h/w DBSR and save current(guest) DBSR */
> > + mfspr r9, SPRN_DBSR
> > + mtspr SPRN_DBSR, r9
> > + isync
> > + andi. r7, r6, NEED_DEBUG_SAVE
> > + beq skip_dbsr_save
> > + /*
> > + * If vcpu->guest_debug flag is set then do not check for
> > + * shared->msr.DE as this debugging (say by QEMU) does not
> > + * depends on shared->msr.de. In these scanerios MSR.DE is
> > + * always set using shared_msr and should be handled always.
> > + */
> > + lwz r7, VCPU_GUEST_DEBUG(r4)
> > + cmpwi r7, 0
> > + bne skip_save_trap_event
> > + PPC_LL r3, VCPU_SHARED(r4)
> > +#ifndef CONFIG_64BIT
> > + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
> > +#else
> > + ld r3, (VCPU_SHARED_MSR)(r3)
> > +#endif
>
> Didn't we have 64-bit access helpers for these?
I will use PPC_LD.
>
> Also this shouldn't happen in the entry/exit code. We have shadow_msr for these
> purposes.
Based on shared_msr.MSR_DE, we set make DBSR (set DBSR_TIE).
Thanks
-Bharat
>
>
>
> Alex
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-10-04 11:06 ` Bhushan Bharat-R65777
@ 2012-10-04 11:25 ` Alexander Graf
2012-10-04 14:22 ` Bhushan Bharat-R65777
0 siblings, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-10-04 11:25 UTC (permalink / raw)
To: Bhushan Bharat-R65777; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
On 04.10.2012, at 13:06, Bhushan Bharat-R65777 wrote:
>
>
>> -----Original Message-----
>> From: Alexander Graf [mailto:agraf@suse.de]
>> Sent: Monday, September 24, 2012 9:50 PM
>> To: Bhushan Bharat-R65777
>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan Bharat-R65777
>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>
>>
>> On 21.08.2012, at 15:52, Bharat Bhushan wrote:
>>
>>> This patch adds the debug stub support on booke/bookehv.
>>> Now QEMU debug stub can use hw breakpoint, watchpoint and
>>> software breakpoint to debug guest.
>>>
>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>> ---
>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++----
>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>> arch/powerpc/kvm/bookehv_interrupts.S | 141 +++++++++++++++++++++++++++++++-
>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
>>> index 61b197e..53479ea 100644
>>> --- a/arch/powerpc/include/asm/kvm.h
>>> +++ b/arch/powerpc/include/asm/kvm.h
>>> @@ -25,6 +25,7 @@
>>> /* Select powerpc specific features in <linux/kvm.h> */
>>> #define __KVM_HAVE_SPAPR_TCE
>>> #define __KVM_HAVE_PPC_SMT
>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>
>>> struct kvm_regs {
>>> __u64 pc;
>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>> __u64 fpr[32];
>>> };
>>>
>>> +
>>> +/*
>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>> + * software breakpoint.
>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>> + * for KVM_DEBUG_EXIT.
>>> + */
>>> +#define KVMPPC_DEBUG_NONE 0x0
>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>> struct kvm_debug_exit_arch {
>>> + __u64 pc;
>>> + /*
>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>> + * set for this address) by qemu then it is supposed to inject this
>>> + * exception to guest.
>>> + */
>>> + __u32 exception;
>>> + /*
>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>> + * (read, write or both) and software breakpoint.
>>> + */
>>> + __u32 status;
>>> };
>>>
>>> /* for KVM_SET_GUEST_DEBUG */
>>> @@ -276,10 +301,6 @@ struct kvm_guest_debug_arch {
>>> * Type denotes h/w breakpoint, read watchpoint, write
>>> * watchpoint or watchpoint (both read and write).
>>> */
>>> -#define KVMPPC_DEBUG_NOTYPE 0x0
>>> -#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>> -#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>> -#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>> __u32 type;
>>> __u32 pad1;
>>> __u64 pad2;
>>> diff --git a/arch/powerpc/include/asm/kvm_host.h
>> b/arch/powerpc/include/asm/kvm_host.h
>>> index c7219c1..3ba465a 100644
>>> --- a/arch/powerpc/include/asm/kvm_host.h
>>> +++ b/arch/powerpc/include/asm/kvm_host.h
>>> @@ -496,7 +496,12 @@ struct kvm_vcpu_arch {
>>> u32 mmucfg;
>>> u32 epr;
>>> u32 crit_save;
>>> + /* guest debug registers*/
>>> struct kvmppc_booke_debug_reg dbg_reg;
>>> + /* shadow debug registers */
>>> + struct kvmppc_booke_debug_reg shadow_dbg_reg;
>>> + /* host debug registers*/
>>> + struct kvmppc_booke_debug_reg host_dbg_reg;
>>> #endif
>>> gpa_t paddr_accessed;
>>> gva_t vaddr_accessed;
>>> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-
>> offsets.c
>>> index 555448e..6987821 100644
>>> --- a/arch/powerpc/kernel/asm-offsets.c
>>> +++ b/arch/powerpc/kernel/asm-offsets.c
>>> @@ -564,6 +564,32 @@ int main(void)
>>> DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
>>> DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
>>> DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
>>> + DEFINE(VCPU_DBSR, offsetof(struct kvm_vcpu, arch.dbsr));
>>> + DEFINE(VCPU_SHADOW_DBG, offsetof(struct kvm_vcpu, arch.shadow_dbg_reg));
>>> + DEFINE(VCPU_HOST_DBG, offsetof(struct kvm_vcpu, arch.host_dbg_reg));
>>> + DEFINE(KVMPPC_DBG_DBCR0, offsetof(struct kvmppc_booke_debug_reg,
>>> + dbcr0));
>>> + DEFINE(KVMPPC_DBG_DBCR1, offsetof(struct kvmppc_booke_debug_reg,
>>> + dbcr1));
>>> + DEFINE(KVMPPC_DBG_DBCR2, offsetof(struct kvmppc_booke_debug_reg,
>>> + dbcr2));
>>> +#ifdef CONFIG_KVM_E500MC
>>> + DEFINE(KVMPPC_DBG_DBCR4, offsetof(struct kvmppc_booke_debug_reg,
>>> + dbcr4));
>>> +#endif
>>> + DEFINE(KVMPPC_DBG_IAC1, offsetof(struct kvmppc_booke_debug_reg,
>>> + iac[0]));
>>> + DEFINE(KVMPPC_DBG_IAC2, offsetof(struct kvmppc_booke_debug_reg,
>>> + iac[1]));
>>> + DEFINE(KVMPPC_DBG_IAC3, offsetof(struct kvmppc_booke_debug_reg,
>>> + iac[2]));
>>> + DEFINE(KVMPPC_DBG_IAC4, offsetof(struct kvmppc_booke_debug_reg,
>>> + iac[3]));
>>> + DEFINE(KVMPPC_DBG_DAC1, offsetof(struct kvmppc_booke_debug_reg,
>>> + dac[0]));
>>> + DEFINE(KVMPPC_DBG_DAC2, offsetof(struct kvmppc_booke_debug_reg,
>>> + dac[1]));
>>> + DEFINE(VCPU_GUEST_DEBUG, offsetof(struct kvm_vcpu, guest_debug));
>>> #endif /* CONFIG_PPC_BOOK3S */
>>> #endif /* CONFIG_KVM */
>>>
>>> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
>>> index dd0e5b8..4d82e34 100644
>>> --- a/arch/powerpc/kvm/booke.c
>>> +++ b/arch/powerpc/kvm/booke.c
>>> @@ -132,6 +132,9 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)
>>>
>>> #ifdef CONFIG_KVM_BOOKE_HV
>>> new_msr |= MSR_GS;
>>> +
>>> + if (vcpu->guest_debug)
>>> + new_msr |= MSR_DE;
>>> #endif
>>>
>>> vcpu->arch.shared->msr = new_msr;
>>> @@ -667,10 +670,21 @@ out:
>>> return ret;
>>> }
>>>
>>> -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
>>> +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
>>> + int exit_nr)
>>> {
>>> enum emulation_result er;
>>>
>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
>>> + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
>>
>> This belongs into the normal emulation code path, behind the same switch() that
>> everything else goes through.
>
> I am not sure I understood correctly. Below is the reason why I placed this code here.
> Instruction where software breakpoint is to be set is replaced by "ehpriv" instruction. On e500v2, this is not a valid instruction can causes program interrupt. On e500mc, "ehpriv" is a valid instruction. Both the exit path calls emulation_exit(), so we have placed the code in this function.
> Do you want this code to be moved in program interrupt exit path for e500v2 and BOOKE_INTERRUPT_HV_PRIV for e500mc?
Ok, in this patch you do (basically):
int emulation_exit()
{
if (inst == DEBUG_INST) {
debug_stuff();
return;
}
switch (inst) {
case INST_A:
foo();
....
}
}
what I want is:
int emulation_exit()
{
switch (inst) {
case INST_A:
foo(); break;
case DEBUG_INST:
debug_stuff(); break;
....
}
}
>
>
>>
>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>> + run->debug.arch.pc = vcpu->arch.pc;
>>> + run->debug.arch.exception = exit_nr;
>>> + run->debug.arch.status = 0;
>>> + kvmppc_account_exit(vcpu, DEBUG_EXITS);
>>> + return RESUME_HOST;
>>> + }
>>> +
>>> er = kvmppc_emulate_instruction(run, vcpu);
>>> switch (er) {
>>> case EMULATE_DONE:
>>> @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run *run, struct
>> kvm_vcpu *vcpu)
>>> default:
>>> BUG();
>>> }
>>> +
>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
>>> + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
>>
>> I don't understand how this is supposed to work. When we enable singlestep, why
>> would we end up in emulation_exit()?
>
> When singlestep is enabled then we set DBCR0[ICMP] and the debug handler should be able to handle this. I think you are right.
>
>>
>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>> + return RESUME_HOST;
>>> + }
>>> +}
>>> +
>>> +static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu *vcpu)
>>> +{
>>> + u32 dbsr;
>>> +
>>> +#ifndef CONFIG_KVM_BOOKE_HV
>>> + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
>>> + vcpu->arch.pc = mfspr(SPRN_DSRR0);
>>> + else
>>> + vcpu->arch.pc = mfspr(SPRN_CSRR0);
>>> +#endif
>>
>> Why doesn't this get handled in the asm code that recovers from the respective
>> exceptions?
>
> Yes. I will remove this.
>
>>
>>> + dbsr = vcpu->arch.dbsr;
>>> +
>>> + run->debug.arch.pc = vcpu->arch.pc;
>>> + run->debug.arch.status = 0;
>>> + vcpu->arch.dbsr = 0;
>>> +
>>> + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
>>> + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
>>> + } else {
>>> + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
>>> + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
>>> + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
>>> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
>>> + }
>>
>> Mind to explain the guest register sharing mechanism you are envisioning? Which
>> registers are used by the guest? Which are used by the host? Who decides what
>> gets used by whom?
>
> struct kvm_vcpu_arch {
> .
> .
>
> /* guest debug registers*/
> struct kvmppc_booke_debug_reg dbg_reg;
> /* shadow debug registers */
> struct kvmppc_booke_debug_reg shadow_dbg_reg;
> /* host debug registers*/
> struct kvmppc_booke_debug_reg host_dbg_reg;
>
> .
> .
> }
>
> dbg_reg: contains the values written by guest.
> shadow_dbg_reg: This contains the actual values to be written on behalf of guest/qemu.
> host_dbg_reg: the debug register value of host (needed for store/retore purpose).
>
> According to current design both, the qemu debug stub and guest, cannot share the debug resources. QEMU debug stub is given priority.
> But host and guest can share all debug registers and host cannot debug guest if it is using the debug resource (which probably does not look like a good case).
Ok. Assume that in guest context, we only ever want guest debugging enabled. If QEMU wants to inject a QEMU breakpoint, it will fiddle with the guest debug registers itself to inject its breakpoint into them.
With that scheme, would we still need shadow debug registers? Or could we remove that one level of indirection?
>
>>
>>> +
>>> + return RESUME_HOST;
>>> }
>>>
>>> static void kvmppc_fill_pt_regs(struct pt_regs *regs)
>>> @@ -843,7 +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
>> kvm_vcpu *vcpu,
>>> break;
>>>
>>> case BOOKE_INTERRUPT_HV_PRIV:
>>> - r = emulation_exit(run, vcpu);
>>> + r = emulation_exit(run, vcpu, exit_nr);
>>> break;
>>>
>>> case BOOKE_INTERRUPT_PROGRAM:
>>> @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
>> kvm_vcpu *vcpu,
>>> break;
>>> }
>>>
>>> - r = emulation_exit(run, vcpu);
>>> + r = emulation_exit(run, vcpu, exit_nr);
>>> break;
>>>
>>> case BOOKE_INTERRUPT_FP_UNAVAIL:
>>> @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
>> kvm_vcpu *vcpu,
>>> }
>>>
>>> case BOOKE_INTERRUPT_DEBUG: {
>>> - u32 dbsr;
>>> -
>>> - vcpu->arch.pc = mfspr(SPRN_CSRR0);
>>> -
>>> - /* clear IAC events in DBSR register */
>>> - dbsr = mfspr(SPRN_DBSR);
>>> - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
>>> - mtspr(SPRN_DBSR, dbsr);
>>> -
>>> - run->exit_reason = KVM_EXIT_DEBUG;
>>> + r = kvmppc_handle_debug(run, vcpu);
>>> + if (r == RESUME_HOST) {
>>> + run->debug.arch.exception = exit_nr;
>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>> + }
>>> kvmppc_account_exit(vcpu, DEBUG_EXITS);
>>> - r = RESUME_HOST;
>>> break;
>>> }
>>>
>>> @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,
>> struct kvm_one_reg *reg)
>>> return r;
>>> }
>>>
>>> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
>>> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
>>> +
>>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>>> struct kvm_guest_debug *dbg)
>>> {
>>> - return -EINVAL;
>>> +
>>> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
>>> + /* Clear All debug events */
>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
>>> + vcpu->guest_debug = 0;
>>> + return 0;
>>> + }
>>> +
>>> + vcpu->guest_debug = dbg->control;
>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
>>> +
>>> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
>>> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
>>> +
>>> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
>>> + struct kvmppc_booke_debug_reg *gdbgr =
>>> + &(vcpu->arch.shadow_dbg_reg);
>>> + int n, b = 0, w = 0;
>>> + const u32 bp_code[] = {
>>> + DBCR0_IAC1 | DBCR0_IDM,
>>> + DBCR0_IAC2 | DBCR0_IDM,
>>> + DBCR0_IAC3 | DBCR0_IDM,
>>> + DBCR0_IAC4 | DBCR0_IDM
>>> + };
>>> + const u32 wp_code[] = {
>>> + DBCR0_DAC1W | DBCR0_IDM,
>>> + DBCR0_DAC2W | DBCR0_IDM,
>>> + DBCR0_DAC1R | DBCR0_IDM,
>>> + DBCR0_DAC2R | DBCR0_IDM
>>> + };
>>> +
>>> +#ifndef CONFIG_KVM_BOOKE_HV
>>> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
>>> + DBCR1_IAC3US | DBCR1_IAC4US;
>>> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
>>> +#else
>>> + gdbgr->dbcr1 = 0;
>>> + gdbgr->dbcr2 = 0;
>>> +#endif
>>> +
>>> + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
>>> + u32 type = dbg->arch.bp[n].type;
>>> +
>>> + if (!type)
>>> + break;
>>> +
>>> + if (type & (KVMPPC_DEBUG_WATCH_READ |
>>> + KVMPPC_DEBUG_WATCH_WRITE)) {
>>> + if (w < WP_NUM) {
>>> + if (type & KVMPPC_DEBUG_WATCH_READ)
>>> + gdbgr->dbcr0 |= wp_code[w + 2];
>>> + if (type & KVMPPC_DEBUG_WATCH_WRITE)
>>> + gdbgr->dbcr0 |= wp_code[w];
>>> + gdbgr->dac[w] = dbg->arch.bp[n].addr;
>>> + w++;
>>> + }
>>> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
>>> + if (b < BP_NUM) {
>>> + gdbgr->dbcr0 |= bp_code[b];
>>> + gdbgr->iac[b] = dbg->arch.bp[n].addr;
>>> + b++;
>>> + }
>>> + }
>>> + }
>>> + }
>>> + return 0;
>>> }
>>>
>>> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
>>> diff --git a/arch/powerpc/kvm/booke_interrupts.S
>> b/arch/powerpc/kvm/booke_interrupts.S
>>> index dd9c5d4..2202936 100644
>>> --- a/arch/powerpc/kvm/booke_interrupts.S
>>> +++ b/arch/powerpc/kvm/booke_interrupts.S
>>> @@ -39,6 +39,8 @@
>>> #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4)
>>> #define HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
>>> #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
>>> +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
>>> + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
>>>
>>> #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
>>> (1<<BOOKE_INTERRUPT_DTLB_MISS) | \
>>> @@ -52,6 +54,8 @@
>>> (1<<BOOKE_INTERRUPT_PROGRAM) | \
>>> (1<<BOOKE_INTERRUPT_DTLB_MISS))
>>>
>>> +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
>>> +
>>> .macro __KVM_HANDLER ivor_nr scratch srr0
>>> stw r3, VCPU_GPR(R3)(r4)
>>> stw r5, VCPU_GPR(R5)(r4)
>>> @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
>>> stw r9, VCPU_FAULT_ESR(r4)
>>> ..skip_esr:
>>>
>>> + addi r7, r4, VCPU_HOST_DBG
>>> + mfspr r9, SPRN_DBCR0
>>> + lwz r8, KVMPPC_DBG_DBCR0(r7)
>>> + andis. r9, r9, DBCR0_AC_BITS@h
>>> + beq skip_load_host_debug
>>> + li r9, 0
>>> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
>>> + lwz r9, KVMPPC_DBG_DBCR1(r7)
>>> + mtspr SPRN_DBCR1, r9
>>> + lwz r9, KVMPPC_DBG_DBCR2(r7)
>>> + mtspr SPRN_DBCR2, r9
>>> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
>>> + mtspr SPRN_IAC1, r9
>>> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
>>> + mtspr SPRN_IAC2, r9
>>> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
>>> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
>>> + mtspr SPRN_IAC3, r9
>>> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
>>> + mtspr SPRN_IAC4, r9
>>> +#endif
>>> + lwz r9, KVMPPC_DBG_DAC1+4(r7)
>>> + mtspr SPRN_DAC1, r9
>>> + lwz r9, KVMPPC_DBG_DAC2+4(r7)
>>
>> Yikes. Please move this into a struct, similar to how the MSR save/restore
>> happens on x86.
>>
>> Also, these are 64-bit loads and stores, no?
>
> Ok, you mean PPC_LD/STD?
Yeah :).
>
>>
>>> + mtspr SPRN_DAC2, r9
>>> +skip_load_host_debug:
>>> + /* Clear h/w DBSR and save current(guest) DBSR */
>>> + mfspr r9, SPRN_DBSR
>>> + mtspr SPRN_DBSR, r9
>>> + isync
>>> + andi. r7, r6, NEED_DEBUG_SAVE
>>> + beq skip_dbsr_save
>>> + /*
>>> + * If vcpu->guest_debug flag is set then do not check for
>>> + * shared->msr.DE as this debugging (say by QEMU) does not
>>> + * depends on shared->msr.de. In these scanerios MSR.DE is
>>> + * always set using shared_msr and should be handled always.
>>> + */
>>> + lwz r7, VCPU_GUEST_DEBUG(r4)
>>> + cmpwi r7, 0
>>> + bne skip_save_trap_event
>>> + PPC_LL r3, VCPU_SHARED(r4)
>>> +#ifndef CONFIG_64BIT
>>> + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
>>> +#else
>>> + ld r3, (VCPU_SHARED_MSR)(r3)
>>> +#endif
>>
>> Didn't we have 64-bit access helpers for these?
>
> I will use PPC_LD.
>
>>
>> Also this shouldn't happen in the entry/exit code. We have shadow_msr for these
>> purposes.
>
> Based on shared_msr.MSR_DE, we set make DBSR (set DBSR_TIE).
Hrm. Yeah, must've misread something here.
It would be awesome if we could make the debug register save/restore a bit more relaxed though. For example during preemption.
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-10-04 11:25 ` Alexander Graf
@ 2012-10-04 14:22 ` Bhushan Bharat-R65777
2012-10-04 14:41 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-10-04 14:22 UTC (permalink / raw)
To: Alexander Graf; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
> -----Original Message-----
> From: Alexander Graf [mailto:agraf@suse.de]
> Sent: Thursday, October 04, 2012 4:56 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org
> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>
>
> On 04.10.2012, at 13:06, Bhushan Bharat-R65777 wrote:
>
> >
> >
> >> -----Original Message-----
> >> From: Alexander Graf [mailto:agraf@suse.de]
> >> Sent: Monday, September 24, 2012 9:50 PM
> >> To: Bhushan Bharat-R65777
> >> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan
> >> Bharat-R65777
> >> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
> >>
> >>
> >> On 21.08.2012, at 15:52, Bharat Bhushan wrote:
> >>
> >>> This patch adds the debug stub support on booke/bookehv.
> >>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
> >>> breakpoint to debug guest.
> >>>
> >>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> >>> ---
> >>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
> >>> arch/powerpc/include/asm/kvm_host.h | 5 +
> >>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
> >>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
> --
> >>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
> >>> arch/powerpc/kvm/bookehv_interrupts.S | 141
> +++++++++++++++++++++++++++++++-
> >>> arch/powerpc/kvm/e500mc.c | 3 +-
> >>> 7 files changed, 435 insertions(+), 23 deletions(-)
> >>>
> >>> diff --git a/arch/powerpc/include/asm/kvm.h
> >>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
> >>> --- a/arch/powerpc/include/asm/kvm.h
> >>> +++ b/arch/powerpc/include/asm/kvm.h
> >>> @@ -25,6 +25,7 @@
> >>> /* Select powerpc specific features in <linux/kvm.h> */ #define
> >>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
> >>> +#define __KVM_HAVE_GUEST_DEBUG
> >>>
> >>> struct kvm_regs {
> >>> __u64 pc;
> >>> @@ -264,7 +265,31 @@ struct kvm_fpu {
> >>> __u64 fpr[32];
> >>> };
> >>>
> >>> +
> >>> +/*
> >>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
> >>> + * software breakpoint.
> >>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
> >>> + * for KVM_DEBUG_EXIT.
> >>> + */
> >>> +#define KVMPPC_DEBUG_NONE 0x0
> >>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> >>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> >>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> >>> struct kvm_debug_exit_arch {
> >>> + __u64 pc;
> >>> + /*
> >>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
> >>> + * exit is not handled (say not h/w breakpoint or software breakpoint
> >>> + * set for this address) by qemu then it is supposed to inject this
> >>> + * exception to guest.
> >>> + */
> >>> + __u32 exception;
> >>> + /*
> >>> + * exiting to userspace because of h/w breakpoint, watchpoint
> >>> + * (read, write or both) and software breakpoint.
> >>> + */
> >>> + __u32 status;
> >>> };
> >>>
> >>> /* for KVM_SET_GUEST_DEBUG */
> >>> @@ -276,10 +301,6 @@ struct kvm_guest_debug_arch {
> >>> * Type denotes h/w breakpoint, read watchpoint, write
> >>> * watchpoint or watchpoint (both read and write).
> >>> */
> >>> -#define KVMPPC_DEBUG_NOTYPE 0x0
> >>> -#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
> >>> -#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
> >>> -#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
> >>> __u32 type;
> >>> __u32 pad1;
> >>> __u64 pad2;
> >>> diff --git a/arch/powerpc/include/asm/kvm_host.h
> >> b/arch/powerpc/include/asm/kvm_host.h
> >>> index c7219c1..3ba465a 100644
> >>> --- a/arch/powerpc/include/asm/kvm_host.h
> >>> +++ b/arch/powerpc/include/asm/kvm_host.h
> >>> @@ -496,7 +496,12 @@ struct kvm_vcpu_arch {
> >>> u32 mmucfg;
> >>> u32 epr;
> >>> u32 crit_save;
> >>> + /* guest debug registers*/
> >>> struct kvmppc_booke_debug_reg dbg_reg;
> >>> + /* shadow debug registers */
> >>> + struct kvmppc_booke_debug_reg shadow_dbg_reg;
> >>> + /* host debug registers*/
> >>> + struct kvmppc_booke_debug_reg host_dbg_reg;
> >>> #endif
> >>> gpa_t paddr_accessed;
> >>> gva_t vaddr_accessed;
> >>> diff --git a/arch/powerpc/kernel/asm-offsets.c
> >>> b/arch/powerpc/kernel/asm-
> >> offsets.c
> >>> index 555448e..6987821 100644
> >>> --- a/arch/powerpc/kernel/asm-offsets.c
> >>> +++ b/arch/powerpc/kernel/asm-offsets.c
> >>> @@ -564,6 +564,32 @@ int main(void)
> >>> DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
> >>> DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
> >>> DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
> >>> + DEFINE(VCPU_DBSR, offsetof(struct kvm_vcpu, arch.dbsr));
> >>> + DEFINE(VCPU_SHADOW_DBG, offsetof(struct kvm_vcpu, arch.shadow_dbg_reg));
> >>> + DEFINE(VCPU_HOST_DBG, offsetof(struct kvm_vcpu, arch.host_dbg_reg));
> >>> + DEFINE(KVMPPC_DBG_DBCR0, offsetof(struct kvmppc_booke_debug_reg,
> >>> + dbcr0));
> >>> + DEFINE(KVMPPC_DBG_DBCR1, offsetof(struct kvmppc_booke_debug_reg,
> >>> + dbcr1));
> >>> + DEFINE(KVMPPC_DBG_DBCR2, offsetof(struct kvmppc_booke_debug_reg,
> >>> + dbcr2));
> >>> +#ifdef CONFIG_KVM_E500MC
> >>> + DEFINE(KVMPPC_DBG_DBCR4, offsetof(struct kvmppc_booke_debug_reg,
> >>> + dbcr4));
> >>> +#endif
> >>> + DEFINE(KVMPPC_DBG_IAC1, offsetof(struct kvmppc_booke_debug_reg,
> >>> + iac[0]));
> >>> + DEFINE(KVMPPC_DBG_IAC2, offsetof(struct kvmppc_booke_debug_reg,
> >>> + iac[1]));
> >>> + DEFINE(KVMPPC_DBG_IAC3, offsetof(struct kvmppc_booke_debug_reg,
> >>> + iac[2]));
> >>> + DEFINE(KVMPPC_DBG_IAC4, offsetof(struct kvmppc_booke_debug_reg,
> >>> + iac[3]));
> >>> + DEFINE(KVMPPC_DBG_DAC1, offsetof(struct kvmppc_booke_debug_reg,
> >>> + dac[0]));
> >>> + DEFINE(KVMPPC_DBG_DAC2, offsetof(struct kvmppc_booke_debug_reg,
> >>> + dac[1]));
> >>> + DEFINE(VCPU_GUEST_DEBUG, offsetof(struct kvm_vcpu, guest_debug));
> >>> #endif /* CONFIG_PPC_BOOK3S */
> >>> #endif /* CONFIG_KVM */
> >>>
> >>> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> >>> index dd0e5b8..4d82e34 100644
> >>> --- a/arch/powerpc/kvm/booke.c
> >>> +++ b/arch/powerpc/kvm/booke.c
> >>> @@ -132,6 +132,9 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32
> >>> new_msr)
> >>>
> >>> #ifdef CONFIG_KVM_BOOKE_HV
> >>> new_msr |= MSR_GS;
> >>> +
> >>> + if (vcpu->guest_debug)
> >>> + new_msr |= MSR_DE;
> >>> #endif
> >>>
> >>> vcpu->arch.shared->msr = new_msr;
> >>> @@ -667,10 +670,21 @@ out:
> >>> return ret;
> >>> }
> >>>
> >>> -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu
> >>> *vcpu)
> >>> +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> >>> + int exit_nr)
> >>> {
> >>> enum emulation_result er;
> >>>
> >>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
> >>> + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
> >>
> >> This belongs into the normal emulation code path, behind the same
> >> switch() that everything else goes through.
> >
> > I am not sure I understood correctly. Below is the reason why I placed this
> code here.
> > Instruction where software breakpoint is to be set is replaced by "ehpriv"
> instruction. On e500v2, this is not a valid instruction can causes program
> interrupt. On e500mc, "ehpriv" is a valid instruction. Both the exit path calls
> emulation_exit(), so we have placed the code in this function.
> > Do you want this code to be moved in program interrupt exit path for e500v2
> and BOOKE_INTERRUPT_HV_PRIV for e500mc?
>
> Ok, in this patch you do (basically):
>
> int emulation_exit()
> {
> if (inst == DEBUG_INST) {
> debug_stuff();
> return;
> }
>
> switch (inst) {
> case INST_A:
> foo();
> ....
> }
> }
Are not we doing something like this:
int emulation_exit()
{
if (inst == DEBUG_INST) {
debug_stuff();
return;
}
status = kvmppc_emulate_instruction()
switch (status) {
case FAIL:
foo();
case DONE:
foo1();
....
}
}
Do you want something like this:
int emulation_exit()
{
status = kvmppc_emulate_instruction()
switch (status) {
case FAIL:
if (inst == DEBUG_INST) {
debug_stuff();
return;
}
foo();
case DONE:
foo1();
....
}
}
>
> what I want is:
>
> int emulation_exit()
> {
> switch (inst) {
> case INST_A:
> foo(); break;
> case DEBUG_INST:
> debug_stuff(); break;
> ....
> }
> }
>
> >
> >
> >>
> >>> + run->exit_reason = KVM_EXIT_DEBUG;
> >>> + run->debug.arch.pc = vcpu->arch.pc;
> >>> + run->debug.arch.exception = exit_nr;
> >>> + run->debug.arch.status = 0;
> >>> + kvmppc_account_exit(vcpu, DEBUG_EXITS);
> >>> + return RESUME_HOST;
> >>> + }
> >>> +
> >>> er = kvmppc_emulate_instruction(run, vcpu);
> >>> switch (er) {
> >>> case EMULATE_DONE:
> >>> @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run *run,
> >>> struct
> >> kvm_vcpu *vcpu)
> >>> default:
> >>> BUG();
> >>> }
> >>> +
> >>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
> >>> + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
> >>
> >> I don't understand how this is supposed to work. When we enable
> >> singlestep, why would we end up in emulation_exit()?
> >
> > When singlestep is enabled then we set DBCR0[ICMP] and the debug handler
> should be able to handle this. I think you are right.
> >
> >>
> >>> + run->exit_reason = KVM_EXIT_DEBUG;
> >>> + return RESUME_HOST;
> >>> + }
> >>> +}
> >>> +
> >>> +static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu
> >>> +*vcpu) {
> >>> + u32 dbsr;
> >>> +
> >>> +#ifndef CONFIG_KVM_BOOKE_HV
> >>> + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
> >>> + vcpu->arch.pc = mfspr(SPRN_DSRR0);
> >>> + else
> >>> + vcpu->arch.pc = mfspr(SPRN_CSRR0); #endif
> >>
> >> Why doesn't this get handled in the asm code that recovers from the
> >> respective exceptions?
> >
> > Yes. I will remove this.
> >
> >>
> >>> + dbsr = vcpu->arch.dbsr;
> >>> +
> >>> + run->debug.arch.pc = vcpu->arch.pc;
> >>> + run->debug.arch.status = 0;
> >>> + vcpu->arch.dbsr = 0;
> >>> +
> >>> + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
> >>> + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
> >>> + } else {
> >>> + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
> >>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
> >>> + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
> >>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
> >>> + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
> >>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
> >>> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
> >>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
> >>> + }
> >>
> >> Mind to explain the guest register sharing mechanism you are
> >> envisioning? Which registers are used by the guest? Which are used by
> >> the host? Who decides what gets used by whom?
> >
> > struct kvm_vcpu_arch {
> > .
> > .
> >
> > /* guest debug registers*/
> > struct kvmppc_booke_debug_reg dbg_reg;
> > /* shadow debug registers */
> > struct kvmppc_booke_debug_reg shadow_dbg_reg;
> > /* host debug registers*/
> > struct kvmppc_booke_debug_reg host_dbg_reg;
> >
> > .
> > .
> > }
> >
> > dbg_reg: contains the values written by guest.
> > shadow_dbg_reg: This contains the actual values to be written on behalf of
> guest/qemu.
> > host_dbg_reg: the debug register value of host (needed for store/retore
> purpose).
> >
> > According to current design both, the qemu debug stub and guest, cannot share
> the debug resources. QEMU debug stub is given priority.
> > But host and guest can share all debug registers and host cannot debug guest
> if it is using the debug resource (which probably does not look like a good
> case).
>
> Ok. Assume that in guest context, we only ever want guest debugging enabled. If
> QEMU wants to inject a QEMU breakpoint, it will fiddle with the guest debug
> registers itself to inject its breakpoint into them.
I would like to understand the context you are describing.
QEMU would like to inject debug interrupt to guest only if a debug interrupt happened in guest context and QEMU is not able to handle interrupt (because qemu debug have not set). Right?
In that case the only thing that needed to be updated is guest->DBSR?
>
> With that scheme, would we still need shadow debug registers? Or could we remove
> that one level of indirection?
>
> >
> >>
> >>> +
> >>> + return RESUME_HOST;
> >>> }
> >>>
> >>> static void kvmppc_fill_pt_regs(struct pt_regs *regs) @@ -843,7
> >>> +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
> >> kvm_vcpu *vcpu,
> >>> break;
> >>>
> >>> case BOOKE_INTERRUPT_HV_PRIV:
> >>> - r = emulation_exit(run, vcpu);
> >>> + r = emulation_exit(run, vcpu, exit_nr);
> >>> break;
> >>>
> >>> case BOOKE_INTERRUPT_PROGRAM:
> >>> @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run,
> >>> struct
> >> kvm_vcpu *vcpu,
> >>> break;
> >>> }
> >>>
> >>> - r = emulation_exit(run, vcpu);
> >>> + r = emulation_exit(run, vcpu, exit_nr);
> >>> break;
> >>>
> >>> case BOOKE_INTERRUPT_FP_UNAVAIL:
> >>> @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run *run,
> >>> struct
> >> kvm_vcpu *vcpu,
> >>> }
> >>>
> >>> case BOOKE_INTERRUPT_DEBUG: {
> >>> - u32 dbsr;
> >>> -
> >>> - vcpu->arch.pc = mfspr(SPRN_CSRR0);
> >>> -
> >>> - /* clear IAC events in DBSR register */
> >>> - dbsr = mfspr(SPRN_DBSR);
> >>> - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
> >>> - mtspr(SPRN_DBSR, dbsr);
> >>> -
> >>> - run->exit_reason = KVM_EXIT_DEBUG;
> >>> + r = kvmppc_handle_debug(run, vcpu);
> >>> + if (r == RESUME_HOST) {
> >>> + run->debug.arch.exception = exit_nr;
> >>> + run->exit_reason = KVM_EXIT_DEBUG;
> >>> + }
> >>> kvmppc_account_exit(vcpu, DEBUG_EXITS);
> >>> - r = RESUME_HOST;
> >>> break;
> >>> }
> >>>
> >>> @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct
> >>> kvm_vcpu *vcpu,
> >> struct kvm_one_reg *reg)
> >>> return r;
> >>> }
> >>>
> >>> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
> >>> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
> >>> +
> >>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
> >>> struct kvm_guest_debug *dbg)
> >>> {
> >>> - return -EINVAL;
> >>> +
> >>> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
> >>> + /* Clear All debug events */
> >>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> >>> + vcpu->guest_debug = 0;
> >>> + return 0;
> >>> + }
> >>> +
> >>> + vcpu->guest_debug = dbg->control;
> >>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> >>> +
> >>> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
> >>> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
> >>> +
> >>> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
> >>> + struct kvmppc_booke_debug_reg *gdbgr =
> >>> + &(vcpu->arch.shadow_dbg_reg);
> >>> + int n, b = 0, w = 0;
> >>> + const u32 bp_code[] = {
> >>> + DBCR0_IAC1 | DBCR0_IDM,
> >>> + DBCR0_IAC2 | DBCR0_IDM,
> >>> + DBCR0_IAC3 | DBCR0_IDM,
> >>> + DBCR0_IAC4 | DBCR0_IDM
> >>> + };
> >>> + const u32 wp_code[] = {
> >>> + DBCR0_DAC1W | DBCR0_IDM,
> >>> + DBCR0_DAC2W | DBCR0_IDM,
> >>> + DBCR0_DAC1R | DBCR0_IDM,
> >>> + DBCR0_DAC2R | DBCR0_IDM
> >>> + };
> >>> +
> >>> +#ifndef CONFIG_KVM_BOOKE_HV
> >>> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
> >>> + DBCR1_IAC3US | DBCR1_IAC4US;
> >>> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; #else
> >>> + gdbgr->dbcr1 = 0;
> >>> + gdbgr->dbcr2 = 0;
> >>> +#endif
> >>> +
> >>> + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
> >>> + u32 type = dbg->arch.bp[n].type;
> >>> +
> >>> + if (!type)
> >>> + break;
> >>> +
> >>> + if (type & (KVMPPC_DEBUG_WATCH_READ |
> >>> + KVMPPC_DEBUG_WATCH_WRITE)) {
> >>> + if (w < WP_NUM) {
> >>> + if (type & KVMPPC_DEBUG_WATCH_READ)
> >>> + gdbgr->dbcr0 |= wp_code[w + 2];
> >>> + if (type & KVMPPC_DEBUG_WATCH_WRITE)
> >>> + gdbgr->dbcr0 |= wp_code[w];
> >>> + gdbgr->dac[w] = dbg->arch.bp[n].addr;
> >>> + w++;
> >>> + }
> >>> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
> >>> + if (b < BP_NUM) {
> >>> + gdbgr->dbcr0 |= bp_code[b];
> >>> + gdbgr->iac[b] = dbg->arch.bp[n].addr;
> >>> + b++;
> >>> + }
> >>> + }
> >>> + }
> >>> + }
> >>> + return 0;
> >>> }
> >>>
> >>> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct
> >>> kvm_fpu *fpu) diff --git a/arch/powerpc/kvm/booke_interrupts.S
> >> b/arch/powerpc/kvm/booke_interrupts.S
> >>> index dd9c5d4..2202936 100644
> >>> --- a/arch/powerpc/kvm/booke_interrupts.S
> >>> +++ b/arch/powerpc/kvm/booke_interrupts.S
> >>> @@ -39,6 +39,8 @@
> >>> #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4) #define
> >>> HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
> >>> #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
> >>> +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
> >>> + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
> >>>
> >>> #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
> >>> (1<<BOOKE_INTERRUPT_DTLB_MISS) | \ @@ -52,6
> >>> +54,8 @@
> >>> (1<<BOOKE_INTERRUPT_PROGRAM) | \
> >>> (1<<BOOKE_INTERRUPT_DTLB_MISS))
> >>>
> >>> +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
> >>> +
> >>> .macro __KVM_HANDLER ivor_nr scratch srr0
> >>> stw r3, VCPU_GPR(R3)(r4)
> >>> stw r5, VCPU_GPR(R5)(r4)
> >>> @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
> >>> stw r9, VCPU_FAULT_ESR(r4)
> >>> ..skip_esr:
> >>>
> >>> + addi r7, r4, VCPU_HOST_DBG
> >>> + mfspr r9, SPRN_DBCR0
> >>> + lwz r8, KVMPPC_DBG_DBCR0(r7)
> >>> + andis. r9, r9, DBCR0_AC_BITS@h
> >>> + beq skip_load_host_debug
> >>> + li r9, 0
> >>> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
> >>> + lwz r9, KVMPPC_DBG_DBCR1(r7)
> >>> + mtspr SPRN_DBCR1, r9
> >>> + lwz r9, KVMPPC_DBG_DBCR2(r7)
> >>> + mtspr SPRN_DBCR2, r9
> >>> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
> >>> + mtspr SPRN_IAC1, r9
> >>> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
> >>> + mtspr SPRN_IAC2, r9
> >>> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
> >>> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
> >>> + mtspr SPRN_IAC3, r9
> >>> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
> >>> + mtspr SPRN_IAC4, r9
> >>> +#endif
> >>> + lwz r9, KVMPPC_DBG_DAC1+4(r7)
> >>> + mtspr SPRN_DAC1, r9
> >>> + lwz r9, KVMPPC_DBG_DAC2+4(r7)
> >>
> >> Yikes. Please move this into a struct, similar to how the MSR
> >> save/restore happens on x86.
> >>
> >> Also, these are 64-bit loads and stores, no?
> >
> > Ok, you mean PPC_LD/STD?
>
> Yeah :).
>
> >
> >>
> >>> + mtspr SPRN_DAC2, r9
> >>> +skip_load_host_debug:
> >>> + /* Clear h/w DBSR and save current(guest) DBSR */
> >>> + mfspr r9, SPRN_DBSR
> >>> + mtspr SPRN_DBSR, r9
> >>> + isync
> >>> + andi. r7, r6, NEED_DEBUG_SAVE
> >>> + beq skip_dbsr_save
> >>> + /*
> >>> + * If vcpu->guest_debug flag is set then do not check for
> >>> + * shared->msr.DE as this debugging (say by QEMU) does not
> >>> + * depends on shared->msr.de. In these scanerios MSR.DE is
> >>> + * always set using shared_msr and should be handled always.
> >>> + */
> >>> + lwz r7, VCPU_GUEST_DEBUG(r4)
> >>> + cmpwi r7, 0
> >>> + bne skip_save_trap_event
> >>> + PPC_LL r3, VCPU_SHARED(r4)
> >>> +#ifndef CONFIG_64BIT
> >>> + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
> >>> +#else
> >>> + ld r3, (VCPU_SHARED_MSR)(r3)
> >>> +#endif
> >>
> >> Didn't we have 64-bit access helpers for these?
> >
> > I will use PPC_LD.
> >
> >>
> >> Also this shouldn't happen in the entry/exit code. We have shadow_msr
> >> for these purposes.
> >
> > Based on shared_msr.MSR_DE, we set make DBSR (set DBSR_TIE).
>
> Hrm. Yeah, must've misread something here.
>
> It would be awesome if we could make the debug register save/restore a bit more
> relaxed though. For example during preemption.
If we delay this save/restore then host cannot do debugging of KVM code. Right?
Thanks
-Bharat
>
>
> Alex
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-10-04 14:22 ` Bhushan Bharat-R65777
@ 2012-10-04 14:41 ` Alexander Graf
2012-10-04 15:19 ` Bhushan Bharat-R65777
0 siblings, 1 reply; 32+ messages in thread
From: Alexander Graf @ 2012-10-04 14:41 UTC (permalink / raw)
To: Bhushan Bharat-R65777; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
On 04.10.2012, at 16:22, Bhushan Bharat-R65777 wrote:
>
>
>> -----Original Message-----
>> From: Alexander Graf [mailto:agraf@suse.de]
>> Sent: Thursday, October 04, 2012 4:56 PM
>> To: Bhushan Bharat-R65777
>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org
>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>
>>
>> On 04.10.2012, at 13:06, Bhushan Bharat-R65777 wrote:
>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: Alexander Graf [mailto:agraf@suse.de]
>>>> Sent: Monday, September 24, 2012 9:50 PM
>>>> To: Bhushan Bharat-R65777
>>>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan
>>>> Bharat-R65777
>>>> Subject: Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
>>>>
>>>>
>>>> On 21.08.2012, at 15:52, Bharat Bhushan wrote:
>>>>
>>>>> This patch adds the debug stub support on booke/bookehv.
>>>>> Now QEMU debug stub can use hw breakpoint, watchpoint and software
>>>>> breakpoint to debug guest.
>>>>>
>>>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>>>> ---
>>>>> arch/powerpc/include/asm/kvm.h | 29 ++++++-
>>>>> arch/powerpc/include/asm/kvm_host.h | 5 +
>>>>> arch/powerpc/kernel/asm-offsets.c | 26 ++++++
>>>>> arch/powerpc/kvm/booke.c | 144 +++++++++++++++++++++++++++++--
>> --
>>>>> arch/powerpc/kvm/booke_interrupts.S | 110 +++++++++++++++++++++++++
>>>>> arch/powerpc/kvm/bookehv_interrupts.S | 141
>> +++++++++++++++++++++++++++++++-
>>>>> arch/powerpc/kvm/e500mc.c | 3 +-
>>>>> 7 files changed, 435 insertions(+), 23 deletions(-)
>>>>>
>>>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>>>> b/arch/powerpc/include/asm/kvm.h index 61b197e..53479ea 100644
>>>>> --- a/arch/powerpc/include/asm/kvm.h
>>>>> +++ b/arch/powerpc/include/asm/kvm.h
>>>>> @@ -25,6 +25,7 @@
>>>>> /* Select powerpc specific features in <linux/kvm.h> */ #define
>>>>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT
>>>>> +#define __KVM_HAVE_GUEST_DEBUG
>>>>>
>>>>> struct kvm_regs {
>>>>> __u64 pc;
>>>>> @@ -264,7 +265,31 @@ struct kvm_fpu {
>>>>> __u64 fpr[32];
>>>>> };
>>>>>
>>>>> +
>>>>> +/*
>>>>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and
>>>>> + * software breakpoint.
>>>>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
>>>>> + * for KVM_DEBUG_EXIT.
>>>>> + */
>>>>> +#define KVMPPC_DEBUG_NONE 0x0
>>>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>> struct kvm_debug_exit_arch {
>>>>> + __u64 pc;
>>>>> + /*
>>>>> + * exception -> returns the exception number. If the KVM_DEBUG_EXIT
>>>>> + * exit is not handled (say not h/w breakpoint or software breakpoint
>>>>> + * set for this address) by qemu then it is supposed to inject this
>>>>> + * exception to guest.
>>>>> + */
>>>>> + __u32 exception;
>>>>> + /*
>>>>> + * exiting to userspace because of h/w breakpoint, watchpoint
>>>>> + * (read, write or both) and software breakpoint.
>>>>> + */
>>>>> + __u32 status;
>>>>> };
>>>>>
>>>>> /* for KVM_SET_GUEST_DEBUG */
>>>>> @@ -276,10 +301,6 @@ struct kvm_guest_debug_arch {
>>>>> * Type denotes h/w breakpoint, read watchpoint, write
>>>>> * watchpoint or watchpoint (both read and write).
>>>>> */
>>>>> -#define KVMPPC_DEBUG_NOTYPE 0x0
>>>>> -#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>>>> -#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>>>> -#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>>>> __u32 type;
>>>>> __u32 pad1;
>>>>> __u64 pad2;
>>>>> diff --git a/arch/powerpc/include/asm/kvm_host.h
>>>> b/arch/powerpc/include/asm/kvm_host.h
>>>>> index c7219c1..3ba465a 100644
>>>>> --- a/arch/powerpc/include/asm/kvm_host.h
>>>>> +++ b/arch/powerpc/include/asm/kvm_host.h
>>>>> @@ -496,7 +496,12 @@ struct kvm_vcpu_arch {
>>>>> u32 mmucfg;
>>>>> u32 epr;
>>>>> u32 crit_save;
>>>>> + /* guest debug registers*/
>>>>> struct kvmppc_booke_debug_reg dbg_reg;
>>>>> + /* shadow debug registers */
>>>>> + struct kvmppc_booke_debug_reg shadow_dbg_reg;
>>>>> + /* host debug registers*/
>>>>> + struct kvmppc_booke_debug_reg host_dbg_reg;
>>>>> #endif
>>>>> gpa_t paddr_accessed;
>>>>> gva_t vaddr_accessed;
>>>>> diff --git a/arch/powerpc/kernel/asm-offsets.c
>>>>> b/arch/powerpc/kernel/asm-
>>>> offsets.c
>>>>> index 555448e..6987821 100644
>>>>> --- a/arch/powerpc/kernel/asm-offsets.c
>>>>> +++ b/arch/powerpc/kernel/asm-offsets.c
>>>>> @@ -564,6 +564,32 @@ int main(void)
>>>>> DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
>>>>> DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
>>>>> DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save));
>>>>> + DEFINE(VCPU_DBSR, offsetof(struct kvm_vcpu, arch.dbsr));
>>>>> + DEFINE(VCPU_SHADOW_DBG, offsetof(struct kvm_vcpu, arch.shadow_dbg_reg));
>>>>> + DEFINE(VCPU_HOST_DBG, offsetof(struct kvm_vcpu, arch.host_dbg_reg));
>>>>> + DEFINE(KVMPPC_DBG_DBCR0, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + dbcr0));
>>>>> + DEFINE(KVMPPC_DBG_DBCR1, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + dbcr1));
>>>>> + DEFINE(KVMPPC_DBG_DBCR2, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + dbcr2));
>>>>> +#ifdef CONFIG_KVM_E500MC
>>>>> + DEFINE(KVMPPC_DBG_DBCR4, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + dbcr4));
>>>>> +#endif
>>>>> + DEFINE(KVMPPC_DBG_IAC1, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + iac[0]));
>>>>> + DEFINE(KVMPPC_DBG_IAC2, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + iac[1]));
>>>>> + DEFINE(KVMPPC_DBG_IAC3, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + iac[2]));
>>>>> + DEFINE(KVMPPC_DBG_IAC4, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + iac[3]));
>>>>> + DEFINE(KVMPPC_DBG_DAC1, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + dac[0]));
>>>>> + DEFINE(KVMPPC_DBG_DAC2, offsetof(struct kvmppc_booke_debug_reg,
>>>>> + dac[1]));
>>>>> + DEFINE(VCPU_GUEST_DEBUG, offsetof(struct kvm_vcpu, guest_debug));
>>>>> #endif /* CONFIG_PPC_BOOK3S */
>>>>> #endif /* CONFIG_KVM */
>>>>>
>>>>> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
>>>>> index dd0e5b8..4d82e34 100644
>>>>> --- a/arch/powerpc/kvm/booke.c
>>>>> +++ b/arch/powerpc/kvm/booke.c
>>>>> @@ -132,6 +132,9 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32
>>>>> new_msr)
>>>>>
>>>>> #ifdef CONFIG_KVM_BOOKE_HV
>>>>> new_msr |= MSR_GS;
>>>>> +
>>>>> + if (vcpu->guest_debug)
>>>>> + new_msr |= MSR_DE;
>>>>> #endif
>>>>>
>>>>> vcpu->arch.shared->msr = new_msr;
>>>>> @@ -667,10 +670,21 @@ out:
>>>>> return ret;
>>>>> }
>>>>>
>>>>> -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu
>>>>> *vcpu)
>>>>> +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
>>>>> + int exit_nr)
>>>>> {
>>>>> enum emulation_result er;
>>>>>
>>>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
>>>>> + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
>>>>
>>>> This belongs into the normal emulation code path, behind the same
>>>> switch() that everything else goes through.
>>>
>>> I am not sure I understood correctly. Below is the reason why I placed this
>> code here.
>>> Instruction where software breakpoint is to be set is replaced by "ehpriv"
>> instruction. On e500v2, this is not a valid instruction can causes program
>> interrupt. On e500mc, "ehpriv" is a valid instruction. Both the exit path calls
>> emulation_exit(), so we have placed the code in this function.
>>> Do you want this code to be moved in program interrupt exit path for e500v2
>> and BOOKE_INTERRUPT_HV_PRIV for e500mc?
>>
>> Ok, in this patch you do (basically):
>>
>> int emulation_exit()
>> {
>> if (inst == DEBUG_INST) {
>> debug_stuff();
>> return;
>> }
>>
>> switch (inst) {
>> case INST_A:
>> foo();
>> ....
>> }
>> }
>
> Are not we doing something like this:
> int emulation_exit()
> {
> if (inst == DEBUG_INST) {
> debug_stuff();
> return;
> }
>
> status = kvmppc_emulate_instruction()
> switch (status) {
> case FAIL:
> foo();
> case DONE:
> foo1();
> ....
> }
> }
>
> Do you want something like this:
>
> int emulation_exit()
> {
>
> status = kvmppc_emulate_instruction()
> switch (status) {
> case FAIL:
> if (inst == DEBUG_INST) {
> debug_stuff();
> return;
> }
> foo();
>
> case DONE:
> foo1();
> ....
> }
> }
No, I want the DEBUG_INST be handled the same as any other instruction we emulate.
>>
>> what I want is:
>>
>> int emulation_exit()
>> {
>> switch (inst) {
>> case INST_A:
>> foo(); break;
>> case DEBUG_INST:
>> debug_stuff(); break;
>> ....
>> }
>> }
>>
>>>
>>>
>>>>
>>>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>>>> + run->debug.arch.pc = vcpu->arch.pc;
>>>>> + run->debug.arch.exception = exit_nr;
>>>>> + run->debug.arch.status = 0;
>>>>> + kvmppc_account_exit(vcpu, DEBUG_EXITS);
>>>>> + return RESUME_HOST;
>>>>> + }
>>>>> +
>>>>> er = kvmppc_emulate_instruction(run, vcpu);
>>>>> switch (er) {
>>>>> case EMULATE_DONE:
>>>>> @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run *run,
>>>>> struct
>>>> kvm_vcpu *vcpu)
>>>>> default:
>>>>> BUG();
>>>>> }
>>>>> +
>>>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
>>>>> + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
>>>>
>>>> I don't understand how this is supposed to work. When we enable
>>>> singlestep, why would we end up in emulation_exit()?
>>>
>>> When singlestep is enabled then we set DBCR0[ICMP] and the debug handler
>> should be able to handle this. I think you are right.
>>>
>>>>
>>>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>>>> + return RESUME_HOST;
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu
>>>>> +*vcpu) {
>>>>> + u32 dbsr;
>>>>> +
>>>>> +#ifndef CONFIG_KVM_BOOKE_HV
>>>>> + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
>>>>> + vcpu->arch.pc = mfspr(SPRN_DSRR0);
>>>>> + else
>>>>> + vcpu->arch.pc = mfspr(SPRN_CSRR0); #endif
>>>>
>>>> Why doesn't this get handled in the asm code that recovers from the
>>>> respective exceptions?
>>>
>>> Yes. I will remove this.
>>>
>>>>
>>>>> + dbsr = vcpu->arch.dbsr;
>>>>> +
>>>>> + run->debug.arch.pc = vcpu->arch.pc;
>>>>> + run->debug.arch.status = 0;
>>>>> + vcpu->arch.dbsr = 0;
>>>>> +
>>>>> + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
>>>>> + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
>>>>> + } else {
>>>>> + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
>>>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
>>>>> + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
>>>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
>>>>> + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
>>>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
>>>>> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
>>>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
>>>>> + }
>>>>
>>>> Mind to explain the guest register sharing mechanism you are
>>>> envisioning? Which registers are used by the guest? Which are used by
>>>> the host? Who decides what gets used by whom?
>>>
>>> struct kvm_vcpu_arch {
>>> .
>>> .
>>>
>>> /* guest debug registers*/
>>> struct kvmppc_booke_debug_reg dbg_reg;
>>> /* shadow debug registers */
>>> struct kvmppc_booke_debug_reg shadow_dbg_reg;
>>> /* host debug registers*/
>>> struct kvmppc_booke_debug_reg host_dbg_reg;
>>>
>>> .
>>> .
>>> }
>>>
>>> dbg_reg: contains the values written by guest.
>>> shadow_dbg_reg: This contains the actual values to be written on behalf of
>> guest/qemu.
>>> host_dbg_reg: the debug register value of host (needed for store/retore
>> purpose).
>>>
>>> According to current design both, the qemu debug stub and guest, cannot share
>> the debug resources. QEMU debug stub is given priority.
>>> But host and guest can share all debug registers and host cannot debug guest
>> if it is using the debug resource (which probably does not look like a good
>> case).
>>
>> Ok. Assume that in guest context, we only ever want guest debugging enabled. If
>> QEMU wants to inject a QEMU breakpoint, it will fiddle with the guest debug
>> registers itself to inject its breakpoint into them.
>
> I would like to understand the context you are describing.
> QEMU would like to inject debug interrupt to guest only if a debug interrupt happened in guest context and QEMU is not able to handle interrupt (because qemu debug have not set). Right?
Yes
> In that case the only thing that needed to be updated is guest->DBSR?
I think you lost me here :)
>
>>
>> With that scheme, would we still need shadow debug registers? Or could we remove
>> that one level of indirection?
>>
>>>
>>>>
>>>>> +
>>>>> + return RESUME_HOST;
>>>>> }
>>>>>
>>>>> static void kvmppc_fill_pt_regs(struct pt_regs *regs) @@ -843,7
>>>>> +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
>>>> kvm_vcpu *vcpu,
>>>>> break;
>>>>>
>>>>> case BOOKE_INTERRUPT_HV_PRIV:
>>>>> - r = emulation_exit(run, vcpu);
>>>>> + r = emulation_exit(run, vcpu, exit_nr);
>>>>> break;
>>>>>
>>>>> case BOOKE_INTERRUPT_PROGRAM:
>>>>> @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run,
>>>>> struct
>>>> kvm_vcpu *vcpu,
>>>>> break;
>>>>> }
>>>>>
>>>>> - r = emulation_exit(run, vcpu);
>>>>> + r = emulation_exit(run, vcpu, exit_nr);
>>>>> break;
>>>>>
>>>>> case BOOKE_INTERRUPT_FP_UNAVAIL:
>>>>> @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run *run,
>>>>> struct
>>>> kvm_vcpu *vcpu,
>>>>> }
>>>>>
>>>>> case BOOKE_INTERRUPT_DEBUG: {
>>>>> - u32 dbsr;
>>>>> -
>>>>> - vcpu->arch.pc = mfspr(SPRN_CSRR0);
>>>>> -
>>>>> - /* clear IAC events in DBSR register */
>>>>> - dbsr = mfspr(SPRN_DBSR);
>>>>> - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
>>>>> - mtspr(SPRN_DBSR, dbsr);
>>>>> -
>>>>> - run->exit_reason = KVM_EXIT_DEBUG;
>>>>> + r = kvmppc_handle_debug(run, vcpu);
>>>>> + if (r == RESUME_HOST) {
>>>>> + run->debug.arch.exception = exit_nr;
>>>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>>>> + }
>>>>> kvmppc_account_exit(vcpu, DEBUG_EXITS);
>>>>> - r = RESUME_HOST;
>>>>> break;
>>>>> }
>>>>>
>>>>> @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct
>>>>> kvm_vcpu *vcpu,
>>>> struct kvm_one_reg *reg)
>>>>> return r;
>>>>> }
>>>>>
>>>>> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
>>>>> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
>>>>> +
>>>>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>>>>> struct kvm_guest_debug *dbg)
>>>>> {
>>>>> - return -EINVAL;
>>>>> +
>>>>> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
>>>>> + /* Clear All debug events */
>>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
>>>>> + vcpu->guest_debug = 0;
>>>>> + return 0;
>>>>> + }
>>>>> +
>>>>> + vcpu->guest_debug = dbg->control;
>>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
>>>>> +
>>>>> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
>>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
>>>>> +
>>>>> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
>>>>> + struct kvmppc_booke_debug_reg *gdbgr =
>>>>> + &(vcpu->arch.shadow_dbg_reg);
>>>>> + int n, b = 0, w = 0;
>>>>> + const u32 bp_code[] = {
>>>>> + DBCR0_IAC1 | DBCR0_IDM,
>>>>> + DBCR0_IAC2 | DBCR0_IDM,
>>>>> + DBCR0_IAC3 | DBCR0_IDM,
>>>>> + DBCR0_IAC4 | DBCR0_IDM
>>>>> + };
>>>>> + const u32 wp_code[] = {
>>>>> + DBCR0_DAC1W | DBCR0_IDM,
>>>>> + DBCR0_DAC2W | DBCR0_IDM,
>>>>> + DBCR0_DAC1R | DBCR0_IDM,
>>>>> + DBCR0_DAC2R | DBCR0_IDM
>>>>> + };
>>>>> +
>>>>> +#ifndef CONFIG_KVM_BOOKE_HV
>>>>> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
>>>>> + DBCR1_IAC3US | DBCR1_IAC4US;
>>>>> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; #else
>>>>> + gdbgr->dbcr1 = 0;
>>>>> + gdbgr->dbcr2 = 0;
>>>>> +#endif
>>>>> +
>>>>> + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
>>>>> + u32 type = dbg->arch.bp[n].type;
>>>>> +
>>>>> + if (!type)
>>>>> + break;
>>>>> +
>>>>> + if (type & (KVMPPC_DEBUG_WATCH_READ |
>>>>> + KVMPPC_DEBUG_WATCH_WRITE)) {
>>>>> + if (w < WP_NUM) {
>>>>> + if (type & KVMPPC_DEBUG_WATCH_READ)
>>>>> + gdbgr->dbcr0 |= wp_code[w + 2];
>>>>> + if (type & KVMPPC_DEBUG_WATCH_WRITE)
>>>>> + gdbgr->dbcr0 |= wp_code[w];
>>>>> + gdbgr->dac[w] = dbg->arch.bp[n].addr;
>>>>> + w++;
>>>>> + }
>>>>> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
>>>>> + if (b < BP_NUM) {
>>>>> + gdbgr->dbcr0 |= bp_code[b];
>>>>> + gdbgr->iac[b] = dbg->arch.bp[n].addr;
>>>>> + b++;
>>>>> + }
>>>>> + }
>>>>> + }
>>>>> + }
>>>>> + return 0;
>>>>> }
>>>>>
>>>>> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct
>>>>> kvm_fpu *fpu) diff --git a/arch/powerpc/kvm/booke_interrupts.S
>>>> b/arch/powerpc/kvm/booke_interrupts.S
>>>>> index dd9c5d4..2202936 100644
>>>>> --- a/arch/powerpc/kvm/booke_interrupts.S
>>>>> +++ b/arch/powerpc/kvm/booke_interrupts.S
>>>>> @@ -39,6 +39,8 @@
>>>>> #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4) #define
>>>>> HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
>>>>> #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
>>>>> +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 | \
>>>>> + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W)
>>>>>
>>>>> #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
>>>>> (1<<BOOKE_INTERRUPT_DTLB_MISS) | \ @@ -52,6
>>>>> +54,8 @@
>>>>> (1<<BOOKE_INTERRUPT_PROGRAM) | \
>>>>> (1<<BOOKE_INTERRUPT_DTLB_MISS))
>>>>>
>>>>> +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
>>>>> +
>>>>> .macro __KVM_HANDLER ivor_nr scratch srr0
>>>>> stw r3, VCPU_GPR(R3)(r4)
>>>>> stw r5, VCPU_GPR(R5)(r4)
>>>>> @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
>>>>> stw r9, VCPU_FAULT_ESR(r4)
>>>>> ..skip_esr:
>>>>>
>>>>> + addi r7, r4, VCPU_HOST_DBG
>>>>> + mfspr r9, SPRN_DBCR0
>>>>> + lwz r8, KVMPPC_DBG_DBCR0(r7)
>>>>> + andis. r9, r9, DBCR0_AC_BITS@h
>>>>> + beq skip_load_host_debug
>>>>> + li r9, 0
>>>>> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
>>>>> + lwz r9, KVMPPC_DBG_DBCR1(r7)
>>>>> + mtspr SPRN_DBCR1, r9
>>>>> + lwz r9, KVMPPC_DBG_DBCR2(r7)
>>>>> + mtspr SPRN_DBCR2, r9
>>>>> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
>>>>> + mtspr SPRN_IAC1, r9
>>>>> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
>>>>> + mtspr SPRN_IAC2, r9
>>>>> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
>>>>> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
>>>>> + mtspr SPRN_IAC3, r9
>>>>> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
>>>>> + mtspr SPRN_IAC4, r9
>>>>> +#endif
>>>>> + lwz r9, KVMPPC_DBG_DAC1+4(r7)
>>>>> + mtspr SPRN_DAC1, r9
>>>>> + lwz r9, KVMPPC_DBG_DAC2+4(r7)
>>>>
>>>> Yikes. Please move this into a struct, similar to how the MSR
>>>> save/restore happens on x86.
>>>>
>>>> Also, these are 64-bit loads and stores, no?
>>>
>>> Ok, you mean PPC_LD/STD?
>>
>> Yeah :).
>>
>>>
>>>>
>>>>> + mtspr SPRN_DAC2, r9
>>>>> +skip_load_host_debug:
>>>>> + /* Clear h/w DBSR and save current(guest) DBSR */
>>>>> + mfspr r9, SPRN_DBSR
>>>>> + mtspr SPRN_DBSR, r9
>>>>> + isync
>>>>> + andi. r7, r6, NEED_DEBUG_SAVE
>>>>> + beq skip_dbsr_save
>>>>> + /*
>>>>> + * If vcpu->guest_debug flag is set then do not check for
>>>>> + * shared->msr.DE as this debugging (say by QEMU) does not
>>>>> + * depends on shared->msr.de. In these scanerios MSR.DE is
>>>>> + * always set using shared_msr and should be handled always.
>>>>> + */
>>>>> + lwz r7, VCPU_GUEST_DEBUG(r4)
>>>>> + cmpwi r7, 0
>>>>> + bne skip_save_trap_event
>>>>> + PPC_LL r3, VCPU_SHARED(r4)
>>>>> +#ifndef CONFIG_64BIT
>>>>> + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
>>>>> +#else
>>>>> + ld r3, (VCPU_SHARED_MSR)(r3)
>>>>> +#endif
>>>>
>>>> Didn't we have 64-bit access helpers for these?
>>>
>>> I will use PPC_LD.
>>>
>>>>
>>>> Also this shouldn't happen in the entry/exit code. We have shadow_msr
>>>> for these purposes.
>>>
>>> Based on shared_msr.MSR_DE, we set make DBSR (set DBSR_TIE).
>>
>> Hrm. Yeah, must've misread something here.
>>
>> It would be awesome if we could make the debug register save/restore a bit more
>> relaxed though. For example during preemption.
>
> If we delay this save/restore then host cannot do debugging of KVM code. Right?
You mean using kdb? Does anyone actually do that?
But let's leave this for later as an optimization.
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* RE: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-10-04 14:41 ` Alexander Graf
@ 2012-10-04 15:19 ` Bhushan Bharat-R65777
2012-10-04 15:40 ` Alexander Graf
0 siblings, 1 reply; 32+ messages in thread
From: Bhushan Bharat-R65777 @ 2012-10-04 15:19 UTC (permalink / raw)
To: Alexander Graf; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
> >>>>> -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu
> >>>>> *vcpu)
> >>>>> +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
> >>>>> + int exit_nr)
> >>>>> {
> >>>>> enum emulation_result er;
> >>>>>
> >>>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
> >>>>> + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
> >>>>
> >>>> This belongs into the normal emulation code path, behind the same
> >>>> switch() that everything else goes through.
> >>>
> >>> I am not sure I understood correctly. Below is the reason why I
> >>> placed this
> >> code here.
> >>> Instruction where software breakpoint is to be set is replaced by "ehpriv"
> >> instruction. On e500v2, this is not a valid instruction can causes
> >> program interrupt. On e500mc, "ehpriv" is a valid instruction. Both
> >> the exit path calls emulation_exit(), so we have placed the code in this
> function.
> >>> Do you want this code to be moved in program interrupt exit path for
> >>> e500v2
> >> and BOOKE_INTERRUPT_HV_PRIV for e500mc?
> >>
> >> Ok, in this patch you do (basically):
> >>
> >> int emulation_exit()
> >> {
> >> if (inst == DEBUG_INST) {
> >> debug_stuff();
> >> return;
> >> }
> >>
> >> switch (inst) {
> >> case INST_A:
> >> foo();
> >> ....
> >> }
> >> }
> >
> > Are not we doing something like this:
> > int emulation_exit()
> > {
> > if (inst == DEBUG_INST) {
> > debug_stuff();
> > return;
> > }
> >
> > status = kvmppc_emulate_instruction()
> > switch (status) {
> > case FAIL:
> > foo();
> > case DONE:
> > foo1();
> > ....
> > }
> > }
> >
> > Do you want something like this:
> >
> > int emulation_exit()
> > {
> >
> > status = kvmppc_emulate_instruction()
> > switch (status) {
> > case FAIL:
> > if (inst == DEBUG_INST) {
> > debug_stuff();
> > return;
> > }
> > foo();
> >
> > case DONE:
> > foo1();
> > ....
> > }
> > }
>
> No, I want the DEBUG_INST be handled the same as any other instruction we
> emulate.
I would like to understand what you are thinking:
What I derived is , add the instruction in kvmppc_emulate_instruction() (or its child function) which,
1) fill the relevant information in run-> , kvmppc_account_exit(vcpu, DEBUG_EXITS); and returns EMULATION_DONE
And in emulation_exit()
status = kvmppc_emulate_instruction()
switch (status) {
case EMULATION_DONE:
if (inst == DEBUG)
return RESUME_HOST;
}
Or
2) kvmppc_account_exit(vcpu, DEBUG_EXITS); returns EMULATION_DONE;
And in emulation_exit()
status = kvmppc_emulate_instruction()
switch (status) {
case EMULATION_DONE:
if (inst == DEBUG) {
fill run->
return RESUME_HOST;
}
}
Or
3) kvmppc_account_exit(vcpu, DEBUG_EXITS); returns a new status type (EMULATION_DEBUG_INST)
And in emulation_exit()
status = kvmppc_emulate_instruction()
switch (status) {
case EMULATION_DEBUG_INST:
fill run->
return RESUME_HOST;
}
>
> >>
> >> what I want is:
> >>
> >> int emulation_exit()
> >> {
> >> switch (inst) {
> >> case INST_A:
> >> foo(); break;
> >> case DEBUG_INST:
> >> debug_stuff(); break;
> >> ....
> >> }
> >> }
> >>
> >>>
> >>>
> >>>>
> >>>>> + run->exit_reason = KVM_EXIT_DEBUG;
> >>>>> + run->debug.arch.pc = vcpu->arch.pc;
> >>>>> + run->debug.arch.exception = exit_nr;
> >>>>> + run->debug.arch.status = 0;
> >>>>> + kvmppc_account_exit(vcpu, DEBUG_EXITS);
> >>>>> + return RESUME_HOST;
> >>>>> + }
> >>>>> +
> >>>>> er = kvmppc_emulate_instruction(run, vcpu);
> >>>>> switch (er) {
> >>>>> case EMULATE_DONE:
> >>>>> @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run
> >>>>> *run, struct
> >>>> kvm_vcpu *vcpu)
> >>>>> default:
> >>>>> BUG();
> >>>>> }
> >>>>> +
> >>>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
> >>>>> + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
> >>>>
> >>>> I don't understand how this is supposed to work. When we enable
> >>>> singlestep, why would we end up in emulation_exit()?
> >>>
> >>> When singlestep is enabled then we set DBCR0[ICMP] and the debug
> >>> handler
> >> should be able to handle this. I think you are right.
> >>>
> >>>>
> >>>>> + run->exit_reason = KVM_EXIT_DEBUG;
> >>>>> + return RESUME_HOST;
> >>>>> + }
> >>>>> +}
> >>>>> +
> >>>>> +static int kvmppc_handle_debug(struct kvm_run *run, struct
> >>>>> +kvm_vcpu
> >>>>> +*vcpu) {
> >>>>> + u32 dbsr;
> >>>>> +
> >>>>> +#ifndef CONFIG_KVM_BOOKE_HV
> >>>>> + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
> >>>>> + vcpu->arch.pc = mfspr(SPRN_DSRR0);
> >>>>> + else
> >>>>> + vcpu->arch.pc = mfspr(SPRN_CSRR0); #endif
> >>>>
> >>>> Why doesn't this get handled in the asm code that recovers from the
> >>>> respective exceptions?
> >>>
> >>> Yes. I will remove this.
> >>>
> >>>>
> >>>>> + dbsr = vcpu->arch.dbsr;
> >>>>> +
> >>>>> + run->debug.arch.pc = vcpu->arch.pc;
> >>>>> + run->debug.arch.status = 0;
> >>>>> + vcpu->arch.dbsr = 0;
> >>>>> +
> >>>>> + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
> >>>>> + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
> >>>>> + } else {
> >>>>> + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
> >>>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
> >>>>> + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
> >>>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
> >>>>> + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
> >>>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
> >>>>> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
> >>>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
> >>>>> + }
> >>>>
> >>>> Mind to explain the guest register sharing mechanism you are
> >>>> envisioning? Which registers are used by the guest? Which are used
> >>>> by the host? Who decides what gets used by whom?
> >>>
> >>> struct kvm_vcpu_arch {
> >>> .
> >>> .
> >>>
> >>> /* guest debug registers*/
> >>> struct kvmppc_booke_debug_reg dbg_reg;
> >>> /* shadow debug registers */
> >>> struct kvmppc_booke_debug_reg shadow_dbg_reg;
> >>> /* host debug registers*/
> >>> struct kvmppc_booke_debug_reg host_dbg_reg;
> >>>
> >>> .
> >>> .
> >>> }
> >>>
> >>> dbg_reg: contains the values written by guest.
> >>> shadow_dbg_reg: This contains the actual values to be written on
> >>> behalf of
> >> guest/qemu.
> >>> host_dbg_reg: the debug register value of host (needed for
> >>> store/retore
> >> purpose).
> >>>
> >>> According to current design both, the qemu debug stub and guest,
> >>> cannot share
> >> the debug resources. QEMU debug stub is given priority.
> >>> But host and guest can share all debug registers and host cannot
> >>> debug guest
> >> if it is using the debug resource (which probably does not look like
> >> a good case).
> >>
> >> Ok. Assume that in guest context, we only ever want guest debugging
> >> enabled. If QEMU wants to inject a QEMU breakpoint, it will fiddle
> >> with the guest debug registers itself to inject its breakpoint into them.
> >
> > I would like to understand the context you are describing.
> > QEMU would like to inject debug interrupt to guest only if a debug interrupt
> happened in guest context and QEMU is not able to handle interrupt (because qemu
> debug have not set). Right?
>
> Yes
>
> > In that case the only thing that needed to be updated is guest->DBSR?
>
> I think you lost me here :)
Really :) . May be I wrote something wrong.
>
> >
> >>
> >> With that scheme, would we still need shadow debug registers? Or
> >> could we remove that one level of indirection?
> >>
> >>>
> >>>>
> >>>>> +
> >>>>> + return RESUME_HOST;
> >>>>> }
> >>>>>
> >>>>> static void kvmppc_fill_pt_regs(struct pt_regs *regs) @@ -843,7
> >>>>> +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
> >>>> kvm_vcpu *vcpu,
> >>>>> break;
> >>>>>
> >>>>> case BOOKE_INTERRUPT_HV_PRIV:
> >>>>> - r = emulation_exit(run, vcpu);
> >>>>> + r = emulation_exit(run, vcpu, exit_nr);
> >>>>> break;
> >>>>>
> >>>>> case BOOKE_INTERRUPT_PROGRAM:
> >>>>> @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run,
> >>>>> struct
> >>>> kvm_vcpu *vcpu,
> >>>>> break;
> >>>>> }
> >>>>>
> >>>>> - r = emulation_exit(run, vcpu);
> >>>>> + r = emulation_exit(run, vcpu, exit_nr);
> >>>>> break;
> >>>>>
> >>>>> case BOOKE_INTERRUPT_FP_UNAVAIL:
> >>>>> @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run
> >>>>> *run, struct
> >>>> kvm_vcpu *vcpu,
> >>>>> }
> >>>>>
> >>>>> case BOOKE_INTERRUPT_DEBUG: {
> >>>>> - u32 dbsr;
> >>>>> -
> >>>>> - vcpu->arch.pc = mfspr(SPRN_CSRR0);
> >>>>> -
> >>>>> - /* clear IAC events in DBSR register */
> >>>>> - dbsr = mfspr(SPRN_DBSR);
> >>>>> - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
> >>>>> - mtspr(SPRN_DBSR, dbsr);
> >>>>> -
> >>>>> - run->exit_reason = KVM_EXIT_DEBUG;
> >>>>> + r = kvmppc_handle_debug(run, vcpu);
> >>>>> + if (r == RESUME_HOST) {
> >>>>> + run->debug.arch.exception = exit_nr;
> >>>>> + run->exit_reason = KVM_EXIT_DEBUG;
> >>>>> + }
> >>>>> kvmppc_account_exit(vcpu, DEBUG_EXITS);
> >>>>> - r = RESUME_HOST;
> >>>>> break;
> >>>>> }
> >>>>>
> >>>>> @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct
> >>>>> kvm_vcpu *vcpu,
> >>>> struct kvm_one_reg *reg)
> >>>>> return r;
> >>>>> }
> >>>>>
> >>>>> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
> >>>>> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
> >>>>> +
> >>>>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
> >>>>> struct kvm_guest_debug *dbg) {
> >>>>> - return -EINVAL;
> >>>>> +
> >>>>> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
> >>>>> + /* Clear All debug events */
> >>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> >>>>> + vcpu->guest_debug = 0;
> >>>>> + return 0;
> >>>>> + }
> >>>>> +
> >>>>> + vcpu->guest_debug = dbg->control;
> >>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> >>>>> +
> >>>>> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
> >>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
> >>>>> +
> >>>>> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
> >>>>> + struct kvmppc_booke_debug_reg *gdbgr =
> >>>>> + &(vcpu->arch.shadow_dbg_reg);
> >>>>> + int n, b = 0, w = 0;
> >>>>> + const u32 bp_code[] = {
> >>>>> + DBCR0_IAC1 | DBCR0_IDM,
> >>>>> + DBCR0_IAC2 | DBCR0_IDM,
> >>>>> + DBCR0_IAC3 | DBCR0_IDM,
> >>>>> + DBCR0_IAC4 | DBCR0_IDM
> >>>>> + };
> >>>>> + const u32 wp_code[] = {
> >>>>> + DBCR0_DAC1W | DBCR0_IDM,
> >>>>> + DBCR0_DAC2W | DBCR0_IDM,
> >>>>> + DBCR0_DAC1R | DBCR0_IDM,
> >>>>> + DBCR0_DAC2R | DBCR0_IDM
> >>>>> + };
> >>>>> +
> >>>>> +#ifndef CONFIG_KVM_BOOKE_HV
> >>>>> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
> >>>>> + DBCR1_IAC3US | DBCR1_IAC4US;
> >>>>> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; #else
> >>>>> + gdbgr->dbcr1 = 0;
> >>>>> + gdbgr->dbcr2 = 0;
> >>>>> +#endif
> >>>>> +
> >>>>> + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
> >>>>> + u32 type = dbg->arch.bp[n].type;
> >>>>> +
> >>>>> + if (!type)
> >>>>> + break;
> >>>>> +
> >>>>> + if (type & (KVMPPC_DEBUG_WATCH_READ |
> >>>>> + KVMPPC_DEBUG_WATCH_WRITE)) {
> >>>>> + if (w < WP_NUM) {
> >>>>> + if (type & KVMPPC_DEBUG_WATCH_READ)
> >>>>> + gdbgr->dbcr0 |= wp_code[w + 2];
> >>>>> + if (type & KVMPPC_DEBUG_WATCH_WRITE)
> >>>>> + gdbgr->dbcr0 |= wp_code[w];
> >>>>> + gdbgr->dac[w] = dbg->arch.bp[n].addr;
> >>>>> + w++;
> >>>>> + }
> >>>>> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
> >>>>> + if (b < BP_NUM) {
> >>>>> + gdbgr->dbcr0 |= bp_code[b];
> >>>>> + gdbgr->iac[b] = dbg->arch.bp[n].addr;
> >>>>> + b++;
> >>>>> + }
> >>>>> + }
> >>>>> + }
> >>>>> + }
> >>>>> + return 0;
> >>>>> }
> >>>>>
> >>>>> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct
> >>>>> kvm_fpu *fpu) diff --git a/arch/powerpc/kvm/booke_interrupts.S
> >>>> b/arch/powerpc/kvm/booke_interrupts.S
> >>>>> index dd9c5d4..2202936 100644
> >>>>> --- a/arch/powerpc/kvm/booke_interrupts.S
> >>>>> +++ b/arch/powerpc/kvm/booke_interrupts.S
> >>>>> @@ -39,6 +39,8 @@
> >>>>> #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4) #define
> >>>>> HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
> >>>>> #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
> >>>>> +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 |
> DBCR0_IAC4 | \
> >>>>> + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R |
> DBCR0_DAC2W)
> >>>>>
> >>>>> #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
> >>>>> (1<<BOOKE_INTERRUPT_DTLB_MISS) | \ @@ -52,6
> >>>>> +54,8 @@
> >>>>> (1<<BOOKE_INTERRUPT_PROGRAM) | \
> >>>>> (1<<BOOKE_INTERRUPT_DTLB_MISS))
> >>>>>
> >>>>> +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
> >>>>> +
> >>>>> .macro __KVM_HANDLER ivor_nr scratch srr0
> >>>>> stw r3, VCPU_GPR(R3)(r4)
> >>>>> stw r5, VCPU_GPR(R5)(r4)
> >>>>> @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
> >>>>> stw r9, VCPU_FAULT_ESR(r4)
> >>>>> ..skip_esr:
> >>>>>
> >>>>> + addi r7, r4, VCPU_HOST_DBG
> >>>>> + mfspr r9, SPRN_DBCR0
> >>>>> + lwz r8, KVMPPC_DBG_DBCR0(r7)
> >>>>> + andis. r9, r9, DBCR0_AC_BITS@h
> >>>>> + beq skip_load_host_debug
> >>>>> + li r9, 0
> >>>>> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
> >>>>> + lwz r9, KVMPPC_DBG_DBCR1(r7)
> >>>>> + mtspr SPRN_DBCR1, r9
> >>>>> + lwz r9, KVMPPC_DBG_DBCR2(r7)
> >>>>> + mtspr SPRN_DBCR2, r9
> >>>>> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
> >>>>> + mtspr SPRN_IAC1, r9
> >>>>> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
> >>>>> + mtspr SPRN_IAC2, r9
> >>>>> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
> >>>>> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
> >>>>> + mtspr SPRN_IAC3, r9
> >>>>> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
> >>>>> + mtspr SPRN_IAC4, r9
> >>>>> +#endif
> >>>>> + lwz r9, KVMPPC_DBG_DAC1+4(r7)
> >>>>> + mtspr SPRN_DAC1, r9
> >>>>> + lwz r9, KVMPPC_DBG_DAC2+4(r7)
> >>>>
> >>>> Yikes. Please move this into a struct, similar to how the MSR
> >>>> save/restore happens on x86.
> >>>>
> >>>> Also, these are 64-bit loads and stores, no?
> >>>
> >>> Ok, you mean PPC_LD/STD?
> >>
> >> Yeah :).
> >>
> >>>
> >>>>
> >>>>> + mtspr SPRN_DAC2, r9
> >>>>> +skip_load_host_debug:
> >>>>> + /* Clear h/w DBSR and save current(guest) DBSR */
> >>>>> + mfspr r9, SPRN_DBSR
> >>>>> + mtspr SPRN_DBSR, r9
> >>>>> + isync
> >>>>> + andi. r7, r6, NEED_DEBUG_SAVE
> >>>>> + beq skip_dbsr_save
> >>>>> + /*
> >>>>> + * If vcpu->guest_debug flag is set then do not check for
> >>>>> + * shared->msr.DE as this debugging (say by QEMU) does not
> >>>>> + * depends on shared->msr.de. In these scanerios MSR.DE is
> >>>>> + * always set using shared_msr and should be handled always.
> >>>>> + */
> >>>>> + lwz r7, VCPU_GUEST_DEBUG(r4)
> >>>>> + cmpwi r7, 0
> >>>>> + bne skip_save_trap_event
> >>>>> + PPC_LL r3, VCPU_SHARED(r4)
> >>>>> +#ifndef CONFIG_64BIT
> >>>>> + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
> >>>>> +#else
> >>>>> + ld r3, (VCPU_SHARED_MSR)(r3)
> >>>>> +#endif
> >>>>
> >>>> Didn't we have 64-bit access helpers for these?
> >>>
> >>> I will use PPC_LD.
> >>>
> >>>>
> >>>> Also this shouldn't happen in the entry/exit code. We have
> >>>> shadow_msr for these purposes.
> >>>
> >>> Based on shared_msr.MSR_DE, we set make DBSR (set DBSR_TIE).
> >>
> >> Hrm. Yeah, must've misread something here.
> >>
> >> It would be awesome if we could make the debug register save/restore
> >> a bit more relaxed though. For example during preemption.
> >
> > If we delay this save/restore then host cannot do debugging of KVM code.
> Right?
>
> You mean using kdb? Does anyone actually do that?
>
> But let's leave this for later as an optimization.
Do you mean that debug registers should be saved/restored in preemption? any specific reason? I think the current save/restore does not add much overhead and we can better it now only, is not it?
Thanks
-Bharat
>
>
> Alex
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 6/6] KVM: booke/bookehv: Add debug stub support
2012-10-04 15:19 ` Bhushan Bharat-R65777
@ 2012-10-04 15:40 ` Alexander Graf
0 siblings, 0 replies; 32+ messages in thread
From: Alexander Graf @ 2012-10-04 15:40 UTC (permalink / raw)
To: Bhushan Bharat-R65777; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
On 04.10.2012, at 17:19, Bhushan Bharat-R65777 wrote:
>
>
>>>>>>> -static int emulation_exit(struct kvm_run *run, struct kvm_vcpu
>>>>>>> *vcpu)
>>>>>>> +static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
>>>>>>> + int exit_nr)
>>>>>>> {
>>>>>>> enum emulation_result er;
>>>>>>>
>>>>>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
>>>>>>> + vcpu->arch.last_inst == KVMPPC_INST_GUEST_GDB) {
>>>>>>
>>>>>> This belongs into the normal emulation code path, behind the same
>>>>>> switch() that everything else goes through.
>>>>>
>>>>> I am not sure I understood correctly. Below is the reason why I
>>>>> placed this
>>>> code here.
>>>>> Instruction where software breakpoint is to be set is replaced by "ehpriv"
>>>> instruction. On e500v2, this is not a valid instruction can causes
>>>> program interrupt. On e500mc, "ehpriv" is a valid instruction. Both
>>>> the exit path calls emulation_exit(), so we have placed the code in this
>> function.
>>>>> Do you want this code to be moved in program interrupt exit path for
>>>>> e500v2
>>>> and BOOKE_INTERRUPT_HV_PRIV for e500mc?
>>>>
>>>> Ok, in this patch you do (basically):
>>>>
>>>> int emulation_exit()
>>>> {
>>>> if (inst == DEBUG_INST) {
>>>> debug_stuff();
>>>> return;
>>>> }
>>>>
>>>> switch (inst) {
>>>> case INST_A:
>>>> foo();
>>>> ....
>>>> }
>>>> }
>>>
>>> Are not we doing something like this:
>>> int emulation_exit()
>>> {
>>> if (inst == DEBUG_INST) {
>>> debug_stuff();
>>> return;
>>> }
>>>
>>> status = kvmppc_emulate_instruction()
>>> switch (status) {
>>> case FAIL:
>>> foo();
>>> case DONE:
>>> foo1();
>>> ....
>>> }
>>> }
>>>
>>> Do you want something like this:
>>>
>>> int emulation_exit()
>>> {
>>>
>>> status = kvmppc_emulate_instruction()
>>> switch (status) {
>>> case FAIL:
>>> if (inst == DEBUG_INST) {
>>> debug_stuff();
>>> return;
>>> }
>>> foo();
>>>
>>> case DONE:
>>> foo1();
>>> ....
>>> }
>>> }
>>
>> No, I want the DEBUG_INST be handled the same as any other instruction we
>> emulate.
>
> I would like to understand what you are thinking:
> What I derived is , add the instruction in kvmppc_emulate_instruction() (or its child function) which,
> 1) fill the relevant information in run-> , kvmppc_account_exit(vcpu, DEBUG_EXITS); and returns EMULATION_DONE
> And in emulation_exit()
> status = kvmppc_emulate_instruction()
> switch (status) {
> case EMULATION_DONE:
> if (inst == DEBUG)
> return RESUME_HOST;
> }
> Or
> 2) kvmppc_account_exit(vcpu, DEBUG_EXITS); returns EMULATION_DONE;
> And in emulation_exit()
> status = kvmppc_emulate_instruction()
> switch (status) {
> case EMULATION_DONE:
> if (inst == DEBUG) {
> fill run->
> return RESUME_HOST;
> }
> }
>
> Or
> 3) kvmppc_account_exit(vcpu, DEBUG_EXITS); returns a new status type (EMULATION_DEBUG_INST)
> And in emulation_exit()
> status = kvmppc_emulate_instruction()
> switch (status) {
> case EMULATION_DEBUG_INST:
> fill run->
> return RESUME_HOST;
> }
This one :).
>
>>
>>>>
>>>> what I want is:
>>>>
>>>> int emulation_exit()
>>>> {
>>>> switch (inst) {
>>>> case INST_A:
>>>> foo(); break;
>>>> case DEBUG_INST:
>>>> debug_stuff(); break;
>>>> ....
>>>> }
>>>> }
>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>>>>>> + run->debug.arch.pc = vcpu->arch.pc;
>>>>>>> + run->debug.arch.exception = exit_nr;
>>>>>>> + run->debug.arch.status = 0;
>>>>>>> + kvmppc_account_exit(vcpu, DEBUG_EXITS);
>>>>>>> + return RESUME_HOST;
>>>>>>> + }
>>>>>>> +
>>>>>>> er = kvmppc_emulate_instruction(run, vcpu);
>>>>>>> switch (er) {
>>>>>>> case EMULATE_DONE:
>>>>>>> @@ -697,6 +711,44 @@ static int emulation_exit(struct kvm_run
>>>>>>> *run, struct
>>>>>> kvm_vcpu *vcpu)
>>>>>>> default:
>>>>>>> BUG();
>>>>>>> }
>>>>>>> +
>>>>>>> + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_ENABLE) &&
>>>>>>> + (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
>>>>>>
>>>>>> I don't understand how this is supposed to work. When we enable
>>>>>> singlestep, why would we end up in emulation_exit()?
>>>>>
>>>>> When singlestep is enabled then we set DBCR0[ICMP] and the debug
>>>>> handler
>>>> should be able to handle this. I think you are right.
>>>>>
>>>>>>
>>>>>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>>>>>> + return RESUME_HOST;
>>>>>>> + }
>>>>>>> +}
>>>>>>> +
>>>>>>> +static int kvmppc_handle_debug(struct kvm_run *run, struct
>>>>>>> +kvm_vcpu
>>>>>>> +*vcpu) {
>>>>>>> + u32 dbsr;
>>>>>>> +
>>>>>>> +#ifndef CONFIG_KVM_BOOKE_HV
>>>>>>> + if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
>>>>>>> + vcpu->arch.pc = mfspr(SPRN_DSRR0);
>>>>>>> + else
>>>>>>> + vcpu->arch.pc = mfspr(SPRN_CSRR0); #endif
>>>>>>
>>>>>> Why doesn't this get handled in the asm code that recovers from the
>>>>>> respective exceptions?
>>>>>
>>>>> Yes. I will remove this.
>>>>>
>>>>>>
>>>>>>> + dbsr = vcpu->arch.dbsr;
>>>>>>> +
>>>>>>> + run->debug.arch.pc = vcpu->arch.pc;
>>>>>>> + run->debug.arch.status = 0;
>>>>>>> + vcpu->arch.dbsr = 0;
>>>>>>> +
>>>>>>> + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
>>>>>>> + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
>>>>>>> + } else {
>>>>>>> + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
>>>>>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
>>>>>>> + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
>>>>>>> + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
>>>>>>> + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
>>>>>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[0];
>>>>>>> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
>>>>>>> + run->debug.arch.pc = vcpu->arch.shadow_dbg_reg.dac[1];
>>>>>>> + }
>>>>>>
>>>>>> Mind to explain the guest register sharing mechanism you are
>>>>>> envisioning? Which registers are used by the guest? Which are used
>>>>>> by the host? Who decides what gets used by whom?
>>>>>
>>>>> struct kvm_vcpu_arch {
>>>>> .
>>>>> .
>>>>>
>>>>> /* guest debug registers*/
>>>>> struct kvmppc_booke_debug_reg dbg_reg;
>>>>> /* shadow debug registers */
>>>>> struct kvmppc_booke_debug_reg shadow_dbg_reg;
>>>>> /* host debug registers*/
>>>>> struct kvmppc_booke_debug_reg host_dbg_reg;
>>>>>
>>>>> .
>>>>> .
>>>>> }
>>>>>
>>>>> dbg_reg: contains the values written by guest.
>>>>> shadow_dbg_reg: This contains the actual values to be written on
>>>>> behalf of
>>>> guest/qemu.
>>>>> host_dbg_reg: the debug register value of host (needed for
>>>>> store/retore
>>>> purpose).
>>>>>
>>>>> According to current design both, the qemu debug stub and guest,
>>>>> cannot share
>>>> the debug resources. QEMU debug stub is given priority.
>>>>> But host and guest can share all debug registers and host cannot
>>>>> debug guest
>>>> if it is using the debug resource (which probably does not look like
>>>> a good case).
>>>>
>>>> Ok. Assume that in guest context, we only ever want guest debugging
>>>> enabled. If QEMU wants to inject a QEMU breakpoint, it will fiddle
>>>> with the guest debug registers itself to inject its breakpoint into them.
>>>
>>> I would like to understand the context you are describing.
>>> QEMU would like to inject debug interrupt to guest only if a debug interrupt
>> happened in guest context and QEMU is not able to handle interrupt (because qemu
>> debug have not set). Right?
>>
>> Yes
>>
>>> In that case the only thing that needed to be updated is guest->DBSR?
>>
>> I think you lost me here :)
>
> Really :) . May be I wrote something wrong.
>
>>
>>>
>>>>
>>>> With that scheme, would we still need shadow debug registers? Or
>>>> could we remove that one level of indirection?
>>>>
>>>>>
>>>>>>
>>>>>>> +
>>>>>>> + return RESUME_HOST;
>>>>>>> }
>>>>>>>
>>>>>>> static void kvmppc_fill_pt_regs(struct pt_regs *regs) @@ -843,7
>>>>>>> +895,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
>>>>>> kvm_vcpu *vcpu,
>>>>>>> break;
>>>>>>>
>>>>>>> case BOOKE_INTERRUPT_HV_PRIV:
>>>>>>> - r = emulation_exit(run, vcpu);
>>>>>>> + r = emulation_exit(run, vcpu, exit_nr);
>>>>>>> break;
>>>>>>>
>>>>>>> case BOOKE_INTERRUPT_PROGRAM:
>>>>>>> @@ -862,7 +914,7 @@ int kvmppc_handle_exit(struct kvm_run *run,
>>>>>>> struct
>>>>>> kvm_vcpu *vcpu,
>>>>>>> break;
>>>>>>> }
>>>>>>>
>>>>>>> - r = emulation_exit(run, vcpu);
>>>>>>> + r = emulation_exit(run, vcpu, exit_nr);
>>>>>>> break;
>>>>>>>
>>>>>>> case BOOKE_INTERRUPT_FP_UNAVAIL:
>>>>>>> @@ -1052,18 +1104,12 @@ int kvmppc_handle_exit(struct kvm_run
>>>>>>> *run, struct
>>>>>> kvm_vcpu *vcpu,
>>>>>>> }
>>>>>>>
>>>>>>> case BOOKE_INTERRUPT_DEBUG: {
>>>>>>> - u32 dbsr;
>>>>>>> -
>>>>>>> - vcpu->arch.pc = mfspr(SPRN_CSRR0);
>>>>>>> -
>>>>>>> - /* clear IAC events in DBSR register */
>>>>>>> - dbsr = mfspr(SPRN_DBSR);
>>>>>>> - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
>>>>>>> - mtspr(SPRN_DBSR, dbsr);
>>>>>>> -
>>>>>>> - run->exit_reason = KVM_EXIT_DEBUG;
>>>>>>> + r = kvmppc_handle_debug(run, vcpu);
>>>>>>> + if (r == RESUME_HOST) {
>>>>>>> + run->debug.arch.exception = exit_nr;
>>>>>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>>>>>> + }
>>>>>>> kvmppc_account_exit(vcpu, DEBUG_EXITS);
>>>>>>> - r = RESUME_HOST;
>>>>>>> break;
>>>>>>> }
>>>>>>>
>>>>>>> @@ -1403,10 +1449,78 @@ int kvm_vcpu_ioctl_set_one_reg(struct
>>>>>>> kvm_vcpu *vcpu,
>>>>>> struct kvm_one_reg *reg)
>>>>>>> return r;
>>>>>>> }
>>>>>>>
>>>>>>> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM
>>>>>>> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM
>>>>>>> +
>>>>>>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>>>>>>> struct kvm_guest_debug *dbg) {
>>>>>>> - return -EINVAL;
>>>>>>> +
>>>>>>> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
>>>>>>> + /* Clear All debug events */
>>>>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
>>>>>>> + vcpu->guest_debug = 0;
>>>>>>> + return 0;
>>>>>>> + }
>>>>>>> +
>>>>>>> + vcpu->guest_debug = dbg->control;
>>>>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
>>>>>>> +
>>>>>>> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
>>>>>>> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
>>>>>>> +
>>>>>>> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
>>>>>>> + struct kvmppc_booke_debug_reg *gdbgr =
>>>>>>> + &(vcpu->arch.shadow_dbg_reg);
>>>>>>> + int n, b = 0, w = 0;
>>>>>>> + const u32 bp_code[] = {
>>>>>>> + DBCR0_IAC1 | DBCR0_IDM,
>>>>>>> + DBCR0_IAC2 | DBCR0_IDM,
>>>>>>> + DBCR0_IAC3 | DBCR0_IDM,
>>>>>>> + DBCR0_IAC4 | DBCR0_IDM
>>>>>>> + };
>>>>>>> + const u32 wp_code[] = {
>>>>>>> + DBCR0_DAC1W | DBCR0_IDM,
>>>>>>> + DBCR0_DAC2W | DBCR0_IDM,
>>>>>>> + DBCR0_DAC1R | DBCR0_IDM,
>>>>>>> + DBCR0_DAC2R | DBCR0_IDM
>>>>>>> + };
>>>>>>> +
>>>>>>> +#ifndef CONFIG_KVM_BOOKE_HV
>>>>>>> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
>>>>>>> + DBCR1_IAC3US | DBCR1_IAC4US;
>>>>>>> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; #else
>>>>>>> + gdbgr->dbcr1 = 0;
>>>>>>> + gdbgr->dbcr2 = 0;
>>>>>>> +#endif
>>>>>>> +
>>>>>>> + for (n = 0; n < (BP_NUM + WP_NUM); n++) {
>>>>>>> + u32 type = dbg->arch.bp[n].type;
>>>>>>> +
>>>>>>> + if (!type)
>>>>>>> + break;
>>>>>>> +
>>>>>>> + if (type & (KVMPPC_DEBUG_WATCH_READ |
>>>>>>> + KVMPPC_DEBUG_WATCH_WRITE)) {
>>>>>>> + if (w < WP_NUM) {
>>>>>>> + if (type & KVMPPC_DEBUG_WATCH_READ)
>>>>>>> + gdbgr->dbcr0 |= wp_code[w + 2];
>>>>>>> + if (type & KVMPPC_DEBUG_WATCH_WRITE)
>>>>>>> + gdbgr->dbcr0 |= wp_code[w];
>>>>>>> + gdbgr->dac[w] = dbg->arch.bp[n].addr;
>>>>>>> + w++;
>>>>>>> + }
>>>>>>> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
>>>>>>> + if (b < BP_NUM) {
>>>>>>> + gdbgr->dbcr0 |= bp_code[b];
>>>>>>> + gdbgr->iac[b] = dbg->arch.bp[n].addr;
>>>>>>> + b++;
>>>>>>> + }
>>>>>>> + }
>>>>>>> + }
>>>>>>> + }
>>>>>>> + return 0;
>>>>>>> }
>>>>>>>
>>>>>>> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct
>>>>>>> kvm_fpu *fpu) diff --git a/arch/powerpc/kvm/booke_interrupts.S
>>>>>> b/arch/powerpc/kvm/booke_interrupts.S
>>>>>>> index dd9c5d4..2202936 100644
>>>>>>> --- a/arch/powerpc/kvm/booke_interrupts.S
>>>>>>> +++ b/arch/powerpc/kvm/booke_interrupts.S
>>>>>>> @@ -39,6 +39,8 @@
>>>>>>> #define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + 4) #define
>>>>>>> HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
>>>>>>> #define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
>>>>>>> +#define DBCR0_AC_BITS (DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 |
>> DBCR0_IAC4 | \
>>>>>>> + DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R |
>> DBCR0_DAC2W)
>>>>>>>
>>>>>>> #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
>>>>>>> (1<<BOOKE_INTERRUPT_DTLB_MISS) | \ @@ -52,6
>>>>>>> +54,8 @@
>>>>>>> (1<<BOOKE_INTERRUPT_PROGRAM) | \
>>>>>>> (1<<BOOKE_INTERRUPT_DTLB_MISS))
>>>>>>>
>>>>>>> +#define NEED_DEBUG_SAVE (1<<BOOKE_INTERRUPT_DEBUG)
>>>>>>> +
>>>>>>> .macro __KVM_HANDLER ivor_nr scratch srr0
>>>>>>> stw r3, VCPU_GPR(R3)(r4)
>>>>>>> stw r5, VCPU_GPR(R5)(r4)
>>>>>>> @@ -212,6 +216,61 @@ _GLOBAL(kvmppc_resume_host)
>>>>>>> stw r9, VCPU_FAULT_ESR(r4)
>>>>>>> ..skip_esr:
>>>>>>>
>>>>>>> + addi r7, r4, VCPU_HOST_DBG
>>>>>>> + mfspr r9, SPRN_DBCR0
>>>>>>> + lwz r8, KVMPPC_DBG_DBCR0(r7)
>>>>>>> + andis. r9, r9, DBCR0_AC_BITS@h
>>>>>>> + beq skip_load_host_debug
>>>>>>> + li r9, 0
>>>>>>> + mtspr SPRN_DBCR0, r9 /* disable all debug event */
>>>>>>> + lwz r9, KVMPPC_DBG_DBCR1(r7)
>>>>>>> + mtspr SPRN_DBCR1, r9
>>>>>>> + lwz r9, KVMPPC_DBG_DBCR2(r7)
>>>>>>> + mtspr SPRN_DBCR2, r9
>>>>>>> + lwz r9, KVMPPC_DBG_IAC1+4(r7)
>>>>>>> + mtspr SPRN_IAC1, r9
>>>>>>> + lwz r9, KVMPPC_DBG_IAC2+4(r7)
>>>>>>> + mtspr SPRN_IAC2, r9
>>>>>>> +#if CONFIG_PPC_ADV_DEBUG_IACS > 2
>>>>>>> + lwz r9, KVMPPC_DBG_IAC3+4(r7)
>>>>>>> + mtspr SPRN_IAC3, r9
>>>>>>> + lwz r9, KVMPPC_DBG_IAC4+4(r7)
>>>>>>> + mtspr SPRN_IAC4, r9
>>>>>>> +#endif
>>>>>>> + lwz r9, KVMPPC_DBG_DAC1+4(r7)
>>>>>>> + mtspr SPRN_DAC1, r9
>>>>>>> + lwz r9, KVMPPC_DBG_DAC2+4(r7)
>>>>>>
>>>>>> Yikes. Please move this into a struct, similar to how the MSR
>>>>>> save/restore happens on x86.
>>>>>>
>>>>>> Also, these are 64-bit loads and stores, no?
>>>>>
>>>>> Ok, you mean PPC_LD/STD?
>>>>
>>>> Yeah :).
>>>>
>>>>>
>>>>>>
>>>>>>> + mtspr SPRN_DAC2, r9
>>>>>>> +skip_load_host_debug:
>>>>>>> + /* Clear h/w DBSR and save current(guest) DBSR */
>>>>>>> + mfspr r9, SPRN_DBSR
>>>>>>> + mtspr SPRN_DBSR, r9
>>>>>>> + isync
>>>>>>> + andi. r7, r6, NEED_DEBUG_SAVE
>>>>>>> + beq skip_dbsr_save
>>>>>>> + /*
>>>>>>> + * If vcpu->guest_debug flag is set then do not check for
>>>>>>> + * shared->msr.DE as this debugging (say by QEMU) does not
>>>>>>> + * depends on shared->msr.de. In these scanerios MSR.DE is
>>>>>>> + * always set using shared_msr and should be handled always.
>>>>>>> + */
>>>>>>> + lwz r7, VCPU_GUEST_DEBUG(r4)
>>>>>>> + cmpwi r7, 0
>>>>>>> + bne skip_save_trap_event
>>>>>>> + PPC_LL r3, VCPU_SHARED(r4)
>>>>>>> +#ifndef CONFIG_64BIT
>>>>>>> + lwz r3, (VCPU_SHARED_MSR + 4)(r3)
>>>>>>> +#else
>>>>>>> + ld r3, (VCPU_SHARED_MSR)(r3)
>>>>>>> +#endif
>>>>>>
>>>>>> Didn't we have 64-bit access helpers for these?
>>>>>
>>>>> I will use PPC_LD.
>>>>>
>>>>>>
>>>>>> Also this shouldn't happen in the entry/exit code. We have
>>>>>> shadow_msr for these purposes.
>>>>>
>>>>> Based on shared_msr.MSR_DE, we set make DBSR (set DBSR_TIE).
>>>>
>>>> Hrm. Yeah, must've misread something here.
>>>>
>>>> It would be awesome if we could make the debug register save/restore
>>>> a bit more relaxed though. For example during preemption.
>>>
>>> If we delay this save/restore then host cannot do debugging of KVM code.
>> Right?
>>
>> You mean using kdb? Does anyone actually do that?
>>
>> But let's leave this for later as an optimization.
>
> Do you mean that debug registers should be saved/restored in preemption? any specific reason? I think the current save/restore does not add much overhead and we can better it now only, is not it?
It definitely adds quite a bit of overhead in a very performance critical path (instruction emulation for v2).
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
2012-10-04 7:14 ` Bhushan Bharat-R65777
@ 2012-12-17 16:56 ` Alexander Graf
0 siblings, 0 replies; 32+ messages in thread
From: Alexander Graf @ 2012-12-17 16:56 UTC (permalink / raw)
To: Bhushan Bharat-R65777; +Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
On 04.10.2012, at 09:14, Bhushan Bharat-R65777 wrote:
>
>
>> -----Original Message-----
>> From: Alexander Graf [mailto:agraf@suse.de]
>> Sent: Monday, September 24, 2012 9:09 PM
>> To: Bhushan Bharat-R65777
>> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Bhushan Bharat-R65777
>> Subject: Re: [PATCH 4/6] KVM: PPC: debug stub interface parameter defined
>>
>>
>> On 21.08.2012, at 15:51, Bharat Bhushan wrote:
>>
>>> This patch defines the interface parameter for KVM_SET_GUEST_DEBUG
>>> ioctl support. Follow up patches will use this for setting up hardware
>>> breakpoints, watchpoints and software breakpoints.
>>>
>>> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
>>> ---
>>> arch/powerpc/include/asm/kvm.h | 33 +++++++++++++++++++++++++++++++++
>>> arch/powerpc/kvm/book3s.c | 6 ++++++
>>> arch/powerpc/kvm/booke.c | 6 ++++++
>>> arch/powerpc/kvm/powerpc.c | 6 ------
>>> 4 files changed, 45 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/kvm.h
>>> b/arch/powerpc/include/asm/kvm.h index 3c14202..61b197e 100644
>>> --- a/arch/powerpc/include/asm/kvm.h
>>> +++ b/arch/powerpc/include/asm/kvm.h
>>> @@ -269,8 +269,41 @@ struct kvm_debug_exit_arch {
>>>
>>> /* for KVM_SET_GUEST_DEBUG */
>>> struct kvm_guest_debug_arch {
>>> + struct {
>>> + /* H/W breakpoint/watchpoint address */
>>> + __u64 addr;
>>> + /*
>>> + * Type denotes h/w breakpoint, read watchpoint, write
>>> + * watchpoint or watchpoint (both read and write).
>>> + */
>>> +#define KVMPPC_DEBUG_NOTYPE 0x0
>>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
>>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
>>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
>>> + __u32 type;
>>> + __u32 pad1;
>>
>> Why the padding?
>
> Not sure why, I will remove this.
Oh, I think the padding makes sense - depending on the type of interrupt this could for example mean "break when write to address x becomes value y".
I'm not sure the amount of padding and the structure of it is the right way to go though: We probably want to have a union here defining type specific payloads.
>
>>
>>> + __u64 pad2;
>>> + } bp[16];
>>
>> Why 16?
>
> I think for now 6 (4 iac + 2 dac) is sufficient for BOOKE. We kept 16 to have some room for future and other platforms.
Ok :)
Alex
^ permalink raw reply [flat|nested] 32+ messages in thread
end of thread, other threads:[~2012-12-17 16:56 UTC | newest]
Thread overview: 32+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-08-21 13:51 [PATCH 0/6] KVM: BOOKE/BOOKEHV : Added debug stub support Bharat Bhushan
2012-08-21 13:51 ` [PATCH 1/6] KVM: PPC: booke: use vcpu reference from thread_struct Bharat Bhushan
2012-09-24 16:27 ` Alexander Graf
2012-10-04 6:50 ` Bhushan Bharat-R65777
2012-08-21 13:51 ` [PATCH 2/6] KVM: PPC: booke: Allow multiple exception types Bharat Bhushan
2012-08-21 13:51 ` [PATCH 3/6] KVM: PPC: booke: Added debug handler Bharat Bhushan
2012-08-21 13:51 ` [PATCH 4/6] KVM: PPC: debug stub interface parameter defined Bharat Bhushan
2012-09-24 15:38 ` Alexander Graf
2012-10-04 7:14 ` Bhushan Bharat-R65777
2012-12-17 16:56 ` Alexander Graf
2012-10-04 7:37 ` Bhushan Bharat-R65777
2012-08-21 13:51 ` [PATCH 5/6] booke: Added DBCR4 SPR number Bharat Bhushan
2012-09-05 23:24 ` Scott Wood
2012-08-21 13:52 ` [PATCH 6/6] KVM: booke/bookehv: Add debug stub support Bharat Bhushan
2012-09-05 23:23 ` Scott Wood
2012-09-05 23:27 ` Scott Wood
2012-09-06 14:56 ` Bhushan Bharat-R65777
2012-09-06 22:56 ` Scott Wood
2012-09-24 14:46 ` Alexander Graf
2012-09-25 10:38 ` Jan Kiszka
2012-09-25 10:47 ` Alexander Graf
2012-09-25 10:56 ` Jan Kiszka
2012-09-25 10:58 ` Alexander Graf
2012-09-25 11:06 ` Jan Kiszka
2012-09-25 11:10 ` Alexander Graf
2012-09-24 16:20 ` Alexander Graf
2012-10-04 11:06 ` Bhushan Bharat-R65777
2012-10-04 11:25 ` Alexander Graf
2012-10-04 14:22 ` Bhushan Bharat-R65777
2012-10-04 14:41 ` Alexander Graf
2012-10-04 15:19 ` Bhushan Bharat-R65777
2012-10-04 15:40 ` Alexander Graf
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