* Re: [Regression] kvm-userspace: VM freezes after booting FreeDOS
2008-07-10 22:59 ` Mohammed Gamal
@ 2008-07-11 10:53 ` Jan Kiszka
2008-07-11 14:55 ` Mohammed Gamal
0 siblings, 1 reply; 17+ messages in thread
From: Jan Kiszka @ 2008-07-11 10:53 UTC (permalink / raw)
To: Mohammed Gamal; +Cc: Anthony Liguori, kvm, Avi Kivity, Rik van Riel, Jan Kiszka
[-- Attachment #1: Type: text/plain, Size: 2406 bytes --]
Mohammed Gamal wrote:
> On Fri, Jul 11, 2008 at 12:22 AM, Jan Kiszka <jan.kiszka@web.de> wrote:
>> Mohammed Gamal wrote:
>>> On Thu, Jul 10, 2008 at 11:02 PM, Anthony Liguori <anthony@codemonkey.ws> wrote:
>>>> Mohammed Gamal wrote:
>>>>> On Thu, Jul 10, 2008 at 7:31 PM, Anthony Liguori <anthony@codemonkey.ws>
>>>>> wrote:
>>>>>
>>>>>> Mohammed Gamal wrote:
>>>>>>
>>>>>>> After updating my kvm-userspace tree to the latest git tree. I am no
>>>>>>> more able to run FreeDOS. The VM freezes after choosing any of the
>>>>>>> boot options. I am running both latest kvm.git and kvm-userspace.git
>
> <snip>
>
>>> After booting FreeDOS, there are a number of boot options with
>>> different memory extenders, after selecting any option the system
>>> freezes and I get [Stopped] in thr QEMU title bar.
>> "Stopped" - interesting. Seems like something causes QEMU to stop the
>> guest as if some breakpoint was injected.
>>
>> I just downloaded that image and gave it a try against vanilla kvm-70
>> and my own tree which is augment with guest debugging related patches.
>> The former shows your observed behavior (Boot from CD, provide an empty
>> HD image -> press '1' + ENTER -> press '1' -> "Stopped"). The latter kvm
>> tree made QEMU leave with a #GP in the guest. That may point to a debug
>> register related issue, and that patch you identified just happen to
>> make it visible. However, will try to investigate.
>>
>> Jan
>
> I'm interested in seeing these patches. If your tree is hosted online,
> could you please provide me with its location so that I can merge it
> with mine. If not, where can I get them from?
Find both attached. They are a rebase of the kernel side (subset) from
my earlier posted debug rework series. They apply against latest kvm
kernel git in this order:
1. kvm-new-guest-debug-interface-v2.patch
2. kvm-x86-virtualize-debug-registers-v2.patch
The first one makes no difference, but the second one changes the
behavior from reporting a breakpoint to userland to reporting an exception.
I haven't found enough time to dig into this yet, but my gut feeling so
far is that some x86 real mode emulation issue is biting us. Debug
registers are not involved, I've cross-checked with enhanced QEMU
supporting that feature - no invocation of related helper functions there.
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
[-- Attachment #2: kvm-new-guest-debug-interface-v2.patch --]
[-- Type: text/x-patch, Size: 18331 bytes --]
This rips out the support for KVM_DEBUG_GUEST and introduces a new IOCTL
instead: KVM_SET_GUEST_DEBUG. The IOCTL payload consists of a generic
part, controlling the "main switch" and the single-step feature. The
arch specific part adds an x86 interface for intercepting both types of
debug exceptions separately and re-injecting them when the host was not
interested. Moveover, the foundation for guest debugging via debug
registers is layed.
To signal breakpoint events properly back to userland, an arch-specific
data block is now returned along KVM_EXIT_DEBUG. For x86, the arch block
contains the PC, the debug exception, and relevant debug registers to
tell debug events properly apart.
The availability of this new interface is signaled by
KVM_CAP_SET_GUEST_DEBUG. Empty stubs for not yet supported archs are
provided.
Note that both svm and vtx are supported, but only the latter was tested
yet.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
arch/ia64/kvm/kvm-ia64.c | 4 +-
arch/powerpc/kvm/powerpc.c | 4 +-
arch/s390/kvm/kvm-s390.c | 4 +-
arch/x86/kvm/svm.c | 45 +++++++++++++++++++++++-
arch/x86/kvm/vmx.c | 83 ++++++++++++++-------------------------------
arch/x86/kvm/x86.c | 17 ++++-----
include/asm-ia64/kvm.h | 7 +++
include/asm-powerpc/kvm.h | 7 +++
include/asm-s390/kvm.h | 7 +++
include/asm-x86/kvm.h | 18 +++++++++
include/asm-x86/kvm_host.h | 11 +----
include/linux/kvm.h | 51 ++++++++++++++++++---------
include/linux/kvm_host.h | 6 +--
virt/kvm/kvm_main.c | 6 +--
14 files changed, 168 insertions(+), 102 deletions(-)
Index: b/arch/x86/kvm/x86.c
===================================================================
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2825,10 +2825,6 @@ static int __vcpu_run(struct kvm_vcpu *v
down_read(&vcpu->kvm->slots_lock);
vapic_enter(vcpu);
-preempted:
- if (vcpu->guest_debug.enabled)
- kvm_x86_ops->guest_debug_pre(vcpu);
-
again:
if (vcpu->requests)
if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
@@ -2956,7 +2952,7 @@ out:
if (r > 0) {
kvm_resched(vcpu);
down_read(&vcpu->kvm->slots_lock);
- goto preempted;
+ goto again;
}
post_kvm_run_save(vcpu, kvm_run);
@@ -3054,7 +3050,7 @@ int kvm_arch_vcpu_ioctl_get_regs(struct
/*
* Don't leak debug flags in case they were set for guest debugging
*/
- if (vcpu->guest_debug.enabled && vcpu->guest_debug.singlestep)
+ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
regs->rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
vcpu_put(vcpu);
@@ -3667,8 +3663,8 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct
return 0;
}
-int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
- struct kvm_debug_guest *dbg)
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
{
int r;
@@ -3676,6 +3672,11 @@ int kvm_arch_vcpu_ioctl_debug_guest(stru
r = kvm_x86_ops->set_guest_debug(vcpu, dbg);
+ if (dbg->control & KVM_GUESTDBG_INJECT_DB)
+ kvm_queue_exception(vcpu, DB_VECTOR);
+ else if (dbg->control & KVM_GUESTDBG_INJECT_BP)
+ kvm_queue_exception(vcpu, BP_VECTOR);
+
vcpu_put(vcpu);
return r;
Index: b/include/asm-x86/kvm.h
===================================================================
--- a/include/asm-x86/kvm.h
+++ b/include/asm-x86/kvm.h
@@ -205,6 +205,24 @@ struct kvm_pit_channel_state {
__s64 count_load_time;
};
+struct kvm_debug_exit_arch {
+ __u32 exception;
+ __u32 pad;
+ __u64 pc;
+ __u64 dr6;
+ __u64 dr7;
+};
+
+#define KVM_GUESTDBG_USE_SW_BP 0x00010000
+#define KVM_GUESTDBG_USE_HW_BP 0x00020000
+#define KVM_GUESTDBG_INJECT_DB 0x00040000
+#define KVM_GUESTDBG_INJECT_BP 0x00080000
+
+/* for KVM_SET_GUEST_DEBUG */
+struct kvm_guest_debug_arch {
+ __u64 debugreg[8];
+};
+
struct kvm_pit_state {
struct kvm_pit_channel_state channels[3];
};
Index: b/include/asm-x86/kvm_host.h
===================================================================
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -56,6 +56,8 @@
#define KVM_PAGES_PER_HPAGE (KVM_HPAGE_SIZE / PAGE_SIZE)
#define DE_VECTOR 0
+#define DB_VECTOR 1
+#define BP_VECTOR 3
#define UD_VECTOR 6
#define NM_VECTOR 7
#define DF_VECTOR 8
@@ -126,12 +128,6 @@ enum {
#define KVM_NR_MEM_OBJS 40
-struct kvm_guest_debug {
- int enabled;
- unsigned long bp[4];
- int singlestep;
-};
-
/*
* We don't want allocation failures within the mmu code, so we preallocate
* enough memory for a single page fault in a cache.
@@ -395,8 +391,7 @@ struct kvm_x86_ops {
void (*vcpu_put)(struct kvm_vcpu *vcpu);
int (*set_guest_debug)(struct kvm_vcpu *vcpu,
- struct kvm_debug_guest *dbg);
- void (*guest_debug_pre)(struct kvm_vcpu *vcpu);
+ struct kvm_guest_debug *dbg);
int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata);
int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);
u64 (*get_segment_base)(struct kvm_vcpu *vcpu, int seg);
Index: b/include/linux/kvm.h
===================================================================
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -125,6 +125,7 @@ struct kvm_run {
__u64 data_offset; /* relative to kvm_run start */
} io;
struct {
+ struct kvm_debug_exit_arch arch;
} debug;
/* KVM_EXIT_MMIO */
struct {
@@ -216,21 +217,6 @@ struct kvm_interrupt {
__u32 irq;
};
-struct kvm_breakpoint {
- __u32 enabled;
- __u32 padding;
- __u64 address;
-};
-
-/* for KVM_DEBUG_GUEST */
-struct kvm_debug_guest {
- /* int */
- __u32 enabled;
- __u32 pad;
- struct kvm_breakpoint breakpoints[4];
- __u32 singlestep;
-};
-
/* for KVM_GET_DIRTY_LOG */
struct kvm_dirty_log {
__u32 slot;
@@ -291,6 +277,17 @@ struct kvm_s390_interrupt {
__u64 parm64;
};
+/* for KVM_SET_GUEST_DEBUG */
+
+#define KVM_GUESTDBG_ENABLE 0x00000001
+#define KVM_GUESTDBG_SINGLESTEP 0x00000002
+
+struct kvm_guest_debug {
+ __u32 control;
+ __u32 pad;
+ struct kvm_guest_debug_arch arch;
+};
+
#define KVM_TRC_SHIFT 16
/*
* kvm trace categories
@@ -371,6 +368,7 @@ struct kvm_trace_rec {
#define KVM_CAP_PV_MMU 13
#define KVM_CAP_MP_STATE 14
#define KVM_CAP_COALESCED_MMIO 15
+#define KVM_CAP_SET_GUEST_DEBUG 16
/*
* ioctls for VM fds
@@ -411,7 +409,8 @@ struct kvm_trace_rec {
#define KVM_SET_SREGS _IOW(KVMIO, 0x84, struct kvm_sregs)
#define KVM_TRANSLATE _IOWR(KVMIO, 0x85, struct kvm_translation)
#define KVM_INTERRUPT _IOW(KVMIO, 0x86, struct kvm_interrupt)
-#define KVM_DEBUG_GUEST _IOW(KVMIO, 0x87, struct kvm_debug_guest)
+/* KVM_DEBUG_GUEST is no longer supported, use KVM_SET_GUEST_DEBUG instead */
+#define KVM_DEBUG_GUEST __KVM_DEPRECATED_DEBUG_GUEST
#define KVM_GET_MSRS _IOWR(KVMIO, 0x88, struct kvm_msrs)
#define KVM_SET_MSRS _IOW(KVMIO, 0x89, struct kvm_msrs)
#define KVM_SET_CPUID _IOW(KVMIO, 0x8a, struct kvm_cpuid)
@@ -438,6 +437,26 @@ struct kvm_trace_rec {
#define KVM_S390_INITIAL_RESET _IO(KVMIO, 0x97)
#define KVM_GET_MP_STATE _IOR(KVMIO, 0x98, struct kvm_mp_state)
#define KVM_SET_MP_STATE _IOW(KVMIO, 0x99, struct kvm_mp_state)
+/* Available with KVM_CAP_SET_GUEST_DEBUG */
+#define KVM_SET_GUEST_DEBUG _IOW(KVMIO, 0x9a, struct kvm_guest_debug)
+
+/*
+ * Deprecated interfaces
+ */
+struct kvm_breakpoint {
+ __u32 enabled;
+ __u32 padding;
+ __u64 address;
+};
+
+struct kvm_debug_guest {
+ __u32 enabled;
+ __u32 pad;
+ struct kvm_breakpoint breakpoints[4];
+ __u32 singlestep;
+};
+
+#define __KVM_DEPRECATED_DEBUG_GUEST _IOW(KVMIO, 0x87, struct kvm_debug_guest)
#define KVM_TRC_INJ_VIRQ (KVM_TRC_HANDLER + 0x02)
#define KVM_TRC_REDELIVER_EVT (KVM_TRC_HANDLER + 0x03)
Index: b/include/linux/kvm_host.h
===================================================================
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -68,7 +68,7 @@ struct kvm_vcpu {
struct kvm_run *run;
int guest_mode;
unsigned long requests;
- struct kvm_guest_debug guest_debug;
+ unsigned long guest_debug;
int fpu_active;
int guest_fpu_loaded;
wait_queue_head_t wq;
@@ -243,8 +243,8 @@ int kvm_arch_vcpu_ioctl_get_mpstate(stru
struct kvm_mp_state *mp_state);
int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state);
-int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
- struct kvm_debug_guest *dbg);
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg);
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run);
int kvm_arch_init(void *opaque);
Index: b/arch/x86/kvm/vmx.c
===================================================================
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -468,8 +468,13 @@ static void update_exception_bitmap(stru
eb = (1u << PF_VECTOR) | (1u << UD_VECTOR);
if (!vcpu->fpu_active)
eb |= 1u << NM_VECTOR;
- if (vcpu->guest_debug.enabled)
- eb |= 1u << 1;
+ if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
+ if (vcpu->guest_debug &
+ (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
+ eb |= 1u << DB_VECTOR;
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
+ eb |= 1u << BP_VECTOR;
+ }
if (vcpu->arch.rmode.active)
eb = ~0;
if (vm_need_ept())
@@ -963,40 +968,23 @@ static void vmx_cache_reg(struct kvm_vcp
}
}
-static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
+static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
{
- unsigned long dr7 = 0x400;
- int old_singlestep;
-
- old_singlestep = vcpu->guest_debug.singlestep;
-
- vcpu->guest_debug.enabled = dbg->enabled;
- if (vcpu->guest_debug.enabled) {
- int i;
-
- dr7 |= 0x200; /* exact */
- for (i = 0; i < 4; ++i) {
- if (!dbg->breakpoints[i].enabled)
- continue;
- vcpu->guest_debug.bp[i] = dbg->breakpoints[i].address;
- dr7 |= 2 << (i*2); /* global enable */
- dr7 |= 0 << (i*4+16); /* execution breakpoint */
- }
-
- vcpu->guest_debug.singlestep = dbg->singlestep;
- } else
- vcpu->guest_debug.singlestep = 0;
+ int old_debug = vcpu->guest_debug;
+ unsigned long flags;
- if (old_singlestep && !vcpu->guest_debug.singlestep) {
- unsigned long flags;
+ vcpu->guest_debug = dbg->control;
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
+ vcpu->guest_debug = 0;
- flags = vmcs_readl(GUEST_RFLAGS);
+ flags = vmcs_readl(GUEST_RFLAGS);
+ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+ flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
+ else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
- vmcs_writel(GUEST_RFLAGS, flags);
- }
+ vmcs_writel(GUEST_RFLAGS, flags);
update_exception_bitmap(vcpu);
- vmcs_writel(GUEST_DR7, dr7);
return 0;
}
@@ -2213,24 +2201,6 @@ static int vmx_set_tss_addr(struct kvm *
return 0;
}
-static void kvm_guest_debug_pre(struct kvm_vcpu *vcpu)
-{
- struct kvm_guest_debug *dbg = &vcpu->guest_debug;
-
- set_debugreg(dbg->bp[0], 0);
- set_debugreg(dbg->bp[1], 1);
- set_debugreg(dbg->bp[2], 2);
- set_debugreg(dbg->bp[3], 3);
-
- if (dbg->singlestep) {
- unsigned long flags;
-
- flags = vmcs_readl(GUEST_RFLAGS);
- flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
- vmcs_writel(GUEST_RFLAGS, flags);
- }
-}
-
static int handle_rmode_exception(struct kvm_vcpu *vcpu,
int vec, u32 err_code)
{
@@ -2250,7 +2220,7 @@ static int handle_rmode_exception(struct
static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- u32 intr_info, error_code;
+ u32 intr_info, ex_no, error_code;
unsigned long cr2, rip;
u32 vect_info;
enum emulation_result er;
@@ -2308,14 +2278,16 @@ static int handle_exception(struct kvm_v
return 1;
}
- if ((intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK)) ==
- (INTR_TYPE_EXCEPTION | 1)) {
+ ex_no = intr_info & INTR_INFO_VECTOR_MASK;
+ if (ex_no == DB_VECTOR || ex_no == BP_VECTOR) {
kvm_run->exit_reason = KVM_EXIT_DEBUG;
- return 0;
+ kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
+ kvm_run->debug.arch.exception = ex_no;
+ } else {
+ kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
+ kvm_run->ex.exception = ex_no;
+ kvm_run->ex.error_code = error_code;
}
- kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
- kvm_run->ex.exception = intr_info & INTR_INFO_VECTOR_MASK;
- kvm_run->ex.error_code = error_code;
return 0;
}
@@ -3210,7 +3182,6 @@ static struct kvm_x86_ops vmx_x86_ops =
.vcpu_put = vmx_vcpu_put,
.set_guest_debug = set_guest_debug,
- .guest_debug_pre = kvm_guest_debug_pre,
.get_msr = vmx_get_msr,
.set_msr = vmx_set_msr,
.get_segment_base = vmx_get_segment_base,
Index: b/arch/x86/kvm/svm.c
===================================================================
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -898,9 +898,32 @@ static void svm_set_segment(struct kvm_v
}
-static int svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
+static int svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
{
- return -EOPNOTSUPP;
+ int old_debug = vcpu->guest_debug;
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ vcpu->guest_debug = dbg->control;
+
+ svm->vmcb->control.intercept_exceptions &=
+ ~((1 << DB_VECTOR) | (1 << BP_VECTOR));
+ if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
+ if (vcpu->guest_debug &
+ (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
+ svm->vmcb->control.intercept_exceptions |=
+ 1 << DB_VECTOR;
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
+ svm->vmcb->control.intercept_exceptions |=
+ 1 << BP_VECTOR;
+ } else
+ vcpu->guest_debug = 0;
+
+ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+ svm->vmcb->save.rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
+ else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
+ svm->vmcb->save.rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
+
+ return 0;
}
static int svm_get_irq(struct kvm_vcpu *vcpu)
@@ -1012,6 +1035,22 @@ static int pf_interception(struct vcpu_s
return kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code);
}
+static int db_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+ kvm_run->exit_reason = KVM_EXIT_DEBUG;
+ kvm_run->debug.arch.pc = svm->vmcb->save.cs.base + svm->vmcb->save.rip;
+ kvm_run->debug.arch.exception = DB_VECTOR;
+ return 0;
+}
+
+static int bp_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+ kvm_run->exit_reason = KVM_EXIT_DEBUG;
+ kvm_run->debug.arch.pc = svm->vmcb->save.cs.base + svm->vmcb->save.rip;
+ kvm_run->debug.arch.exception = BP_VECTOR;
+ return 0;
+}
+
static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
int er;
@@ -1390,6 +1429,8 @@ static int (*svm_exit_handlers[])(struct
[SVM_EXIT_WRITE_DR3] = emulate_on_interception,
[SVM_EXIT_WRITE_DR5] = emulate_on_interception,
[SVM_EXIT_WRITE_DR7] = emulate_on_interception,
+ [SVM_EXIT_EXCP_BASE + DB_VECTOR] = db_interception,
+ [SVM_EXIT_EXCP_BASE + BP_VECTOR] = bp_interception,
[SVM_EXIT_EXCP_BASE + UD_VECTOR] = ud_interception,
[SVM_EXIT_EXCP_BASE + PF_VECTOR] = pf_interception,
[SVM_EXIT_EXCP_BASE + NM_VECTOR] = nm_interception,
Index: b/virt/kvm/kvm_main.c
===================================================================
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1072,13 +1072,13 @@ out_free2:
r = 0;
break;
}
- case KVM_DEBUG_GUEST: {
- struct kvm_debug_guest dbg;
+ case KVM_SET_GUEST_DEBUG: {
+ struct kvm_guest_debug dbg;
r = -EFAULT;
if (copy_from_user(&dbg, argp, sizeof dbg))
goto out;
- r = kvm_arch_vcpu_ioctl_debug_guest(vcpu, &dbg);
+ r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
if (r)
goto out;
r = 0;
Index: b/arch/ia64/kvm/kvm-ia64.c
===================================================================
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1302,8 +1302,8 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct k
return -EINVAL;
}
-int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
- struct kvm_debug_guest *dbg)
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
{
return -EINVAL;
}
Index: b/arch/powerpc/kvm/powerpc.c
===================================================================
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -243,8 +243,8 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *
{
}
-int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
- struct kvm_debug_guest *dbg)
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
{
return -ENOTSUPP;
}
Index: b/arch/s390/kvm/kvm-s390.c
===================================================================
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -408,8 +408,8 @@ int kvm_arch_vcpu_ioctl_translate(struct
return -EINVAL; /* not implemented yet */
}
-int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
- struct kvm_debug_guest *dbg)
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
{
return -EINVAL; /* not implemented yet */
}
Index: b/include/asm-ia64/kvm.h
===================================================================
--- a/include/asm-ia64/kvm.h
+++ b/include/asm-ia64/kvm.h
@@ -208,4 +208,11 @@ struct kvm_sregs {
struct kvm_fpu {
};
+struct kvm_debug_exit_arch {
+};
+
+/* for KVM_SET_GUEST_DEBUG */
+struct kvm_guest_debug_arch {
+};
+
#endif
Index: b/include/asm-powerpc/kvm.h
===================================================================
--- a/include/asm-powerpc/kvm.h
+++ b/include/asm-powerpc/kvm.h
@@ -52,4 +52,11 @@ struct kvm_fpu {
__u64 fpr[32];
};
+struct kvm_debug_exit_arch {
+};
+
+/* for KVM_SET_GUEST_DEBUG */
+struct kvm_guest_debug_arch {
+};
+
#endif /* __LINUX_KVM_POWERPC_H */
Index: b/include/asm-s390/kvm.h
===================================================================
--- a/include/asm-s390/kvm.h
+++ b/include/asm-s390/kvm.h
@@ -42,4 +42,11 @@ struct kvm_fpu {
__u64 fprs[16];
};
+struct kvm_debug_exit_arch {
+};
+
+/* for KVM_SET_GUEST_DEBUG */
+struct kvm_guest_debug_arch {
+};
+
#endif
[-- Attachment #3: kvm-x86-virtualize-debug-registers-v2.patch --]
[-- Type: text/x-patch, Size: 16447 bytes --]
So far KVM only had basic x86 debug register support, once introduced to
realize guest debugging that way. The guest itself was not able to use
those registers.
This patch now adds (almost) full support for guest self-debugging via
hardware registers. It refactors the code, moving generic parts out of
svm (vmx was already cleaned up by the KVM_SET_GUEST_DEBUG patches), it
ensures that the registers are properly switched between host and guest,
and it also wires up debug register usage by the host. The latter allows
for hardware breakpoints/watchpoints in guest code. If this is enabled,
the guest will only see faked debug registers without functionality,
but with content reflecting the guest's modifications.
Tested on Intel only, but SVM /should/ work as well.
Known limitations: Trapping on tss switch won't work - most probably on
Intel.
Credits also go to Joerg Roedel - I used his debugging series as
platform for this patch.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
arch/x86/kvm/kvm_svm.h | 6 --
arch/x86/kvm/svm.c | 125 +++++++++++++++++----------------------------
arch/x86/kvm/vmx.c | 114 +++++++++++++++++++++++++++++++++++------
arch/x86/kvm/vmx.h | 2
arch/x86/kvm/x86.c | 32 +++++++++++
include/asm-x86/kvm_host.h | 22 +++++++
6 files changed, 200 insertions(+), 101 deletions(-)
Index: b/arch/x86/kvm/kvm_svm.h
===================================================================
--- a/arch/x86/kvm/kvm_svm.h
+++ b/arch/x86/kvm/kvm_svm.h
@@ -18,7 +18,6 @@ static const u32 host_save_user_msrs[] =
};
#define NR_HOST_SAVE_USER_MSRS ARRAY_SIZE(host_save_user_msrs)
-#define NUM_DB_REGS 4
struct kvm_vcpu;
@@ -29,16 +28,11 @@ struct vcpu_svm {
struct svm_cpu_data *svm_data;
uint64_t asid_generation;
- unsigned long db_regs[NUM_DB_REGS];
-
u64 next_rip;
u64 host_user_msrs[NR_HOST_SAVE_USER_MSRS];
u64 host_gs_base;
unsigned long host_cr2;
- unsigned long host_db_regs[NUM_DB_REGS];
- unsigned long host_dr6;
- unsigned long host_dr7;
u32 *msrpm;
};
Index: b/arch/x86/kvm/svm.c
===================================================================
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -36,13 +36,6 @@ MODULE_LICENSE("GPL");
#define IOPM_ALLOC_ORDER 2
#define MSRPM_ALLOC_ORDER 1
-#define DB_VECTOR 1
-#define UD_VECTOR 6
-#define GP_VECTOR 13
-
-#define DR7_GD_MASK (1 << 13)
-#define DR6_BD_MASK (1 << 13)
-
#define SEG_TYPE_LDT 2
#define SEG_TYPE_BUSY_TSS16 3
@@ -158,32 +151,6 @@ static inline void kvm_write_cr2(unsigne
asm volatile ("mov %0, %%cr2" :: "r" (val));
}
-static inline unsigned long read_dr6(void)
-{
- unsigned long dr6;
-
- asm volatile ("mov %%dr6, %0" : "=r" (dr6));
- return dr6;
-}
-
-static inline void write_dr6(unsigned long val)
-{
- asm volatile ("mov %0, %%dr6" :: "r" (val));
-}
-
-static inline unsigned long read_dr7(void)
-{
- unsigned long dr7;
-
- asm volatile ("mov %%dr7, %0" : "=r" (dr7));
- return dr7;
-}
-
-static inline void write_dr7(unsigned long val)
-{
- asm volatile ("mov %0, %%dr7" :: "r" (val));
-}
-
static inline void force_new_asid(struct kvm_vcpu *vcpu)
{
to_svm(vcpu)->asid_generation--;
@@ -657,7 +624,6 @@ static struct kvm_vcpu *svm_create_vcpu(
clear_page(svm->vmcb);
svm->vmcb_pa = page_to_pfn(page) << PAGE_SHIFT;
svm->asid_generation = 0;
- memset(svm->db_regs, 0, sizeof(svm->db_regs));
init_vmcb(svm);
fx_init(&svm->vcpu);
@@ -965,7 +931,29 @@ static void new_asid(struct vcpu_svm *sv
static unsigned long svm_get_dr(struct kvm_vcpu *vcpu, int dr)
{
- unsigned long val = to_svm(vcpu)->db_regs[dr];
+ struct vcpu_svm *svm = to_svm(vcpu);
+ unsigned long val;
+
+ switch (dr) {
+ case 0 ... 3:
+ val = vcpu->arch.db[dr];
+ break;
+ case 6:
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+ val = vcpu->arch.dr6;
+ else
+ val = svm->vmcb->save.dr6;
+ break;
+ case 7:
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+ val = vcpu->arch.dr7;
+ else
+ val = svm->vmcb->save.dr7;
+ break;
+ default:
+ val = 0;
+ }
+
KVMTRACE_2D(DR_READ, vcpu, (u32)dr, (u32)val, handler);
return val;
}
@@ -975,33 +963,40 @@ static void svm_set_dr(struct kvm_vcpu *
{
struct vcpu_svm *svm = to_svm(vcpu);
- *exception = 0;
+ KVMTRACE_2D(DR_WRITE, vcpu, (u32)dr, (u32)value, handler);
- if (svm->vmcb->save.dr7 & DR7_GD_MASK) {
- svm->vmcb->save.dr7 &= ~DR7_GD_MASK;
- svm->vmcb->save.dr6 |= DR6_BD_MASK;
- *exception = DB_VECTOR;
- return;
- }
+ *exception = 0;
switch (dr) {
case 0 ... 3:
- svm->db_regs[dr] = value;
+ vcpu->arch.db[dr] = value;
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ vcpu->arch.eff_db[dr] = value;
return;
case 4 ... 5:
- if (vcpu->arch.cr4 & X86_CR4_DE) {
+ if (vcpu->arch.cr4 & X86_CR4_DE)
*exception = UD_VECTOR;
+ return;
+ case 6:
+ if (value & 0xffffffff00000000ULL) {
+ *exception = GP_VECTOR;
return;
}
- case 7: {
- if (value & ~((1ULL << 32) - 1)) {
+ vcpu->arch.dr6 = (value & DR6_VOLATILE) | DR6_FIXED_1;
+ return;
+ case 7:
+ if (value & 0xffffffff00000000ULL) {
*exception = GP_VECTOR;
return;
}
- svm->vmcb->save.dr7 = value;
+ vcpu->arch.dr7 = (value & DR7_VOLATILE) | DR7_FIXED_1;
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
+ svm->vmcb->save.dr7 = vcpu->arch.dr7;
+ vcpu->arch.switch_db_regs = (value & DR7_BP_EN_MASK);
+ }
return;
- }
default:
+ /* FIXME: Possible case? */
printk(KERN_DEBUG "%s: unexpected dr %u\n",
__func__, dr);
*exception = UD_VECTOR;
@@ -1037,6 +1032,11 @@ static int pf_interception(struct vcpu_s
static int db_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
+ if (!(svm->vcpu.guest_debug &
+ (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))) {
+ kvm_queue_exception(&svm->vcpu, DB_VECTOR);
+ return 1;
+ }
kvm_run->exit_reason = KVM_EXIT_DEBUG;
kvm_run->debug.arch.pc = svm->vmcb->save.cs.base + svm->vmcb->save.rip;
kvm_run->debug.arch.exception = DB_VECTOR;
@@ -1676,22 +1676,6 @@ static int svm_set_tss_addr(struct kvm *
return 0;
}
-static void save_db_regs(unsigned long *db_regs)
-{
- asm volatile ("mov %%dr0, %0" : "=r"(db_regs[0]));
- asm volatile ("mov %%dr1, %0" : "=r"(db_regs[1]));
- asm volatile ("mov %%dr2, %0" : "=r"(db_regs[2]));
- asm volatile ("mov %%dr3, %0" : "=r"(db_regs[3]));
-}
-
-static void load_db_regs(unsigned long *db_regs)
-{
- asm volatile ("mov %0, %%dr0" : : "r"(db_regs[0]));
- asm volatile ("mov %0, %%dr1" : : "r"(db_regs[1]));
- asm volatile ("mov %0, %%dr2" : : "r"(db_regs[2]));
- asm volatile ("mov %0, %%dr3" : : "r"(db_regs[3]));
-}
-
static void svm_flush_tlb(struct kvm_vcpu *vcpu)
{
force_new_asid(vcpu);
@@ -1744,19 +1728,11 @@ static void svm_vcpu_run(struct kvm_vcpu
gs_selector = kvm_read_gs();
ldt_selector = kvm_read_ldt();
svm->host_cr2 = kvm_read_cr2();
- svm->host_dr6 = read_dr6();
- svm->host_dr7 = read_dr7();
svm->vmcb->save.cr2 = vcpu->arch.cr2;
/* required for live migration with NPT */
if (npt_enabled)
svm->vmcb->save.cr3 = vcpu->arch.cr3;
- if (svm->vmcb->save.dr7 & 0xff) {
- write_dr7(0);
- save_db_regs(svm->host_db_regs);
- load_db_regs(svm->db_regs);
- }
-
clgi();
local_irq_enable();
@@ -1866,16 +1842,11 @@ static void svm_vcpu_run(struct kvm_vcpu
#endif
);
- if ((svm->vmcb->save.dr7 & 0xff))
- load_db_regs(svm->host_db_regs);
-
vcpu->arch.cr2 = svm->vmcb->save.cr2;
vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
- write_dr6(svm->host_dr6);
- write_dr7(svm->host_dr7);
kvm_write_cr2(svm->host_cr2);
kvm_load_fs(fs_selector);
Index: b/arch/x86/kvm/vmx.c
===================================================================
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2062,7 +2062,6 @@ static int vmx_vcpu_reset(struct kvm_vcp
kvm_rip_write(vcpu, 0);
kvm_register_write(vcpu, VCPU_REGS_RSP, 0);
- /* todo: dr0 = dr1 = dr2 = dr3 = 0; dr6 = 0xffff0ff0 */
vmcs_writel(GUEST_DR7, 0x400);
vmcs_writel(GUEST_GDTR_BASE, 0);
@@ -2221,7 +2220,7 @@ static int handle_exception(struct kvm_v
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
u32 intr_info, ex_no, error_code;
- unsigned long cr2, rip;
+ unsigned long cr2, rip, dr6;
u32 vect_info;
enum emulation_result er;
@@ -2279,14 +2278,28 @@ static int handle_exception(struct kvm_v
}
ex_no = intr_info & INTR_INFO_VECTOR_MASK;
- if (ex_no == DB_VECTOR || ex_no == BP_VECTOR) {
+ switch (ex_no) {
+ case DB_VECTOR:
+ dr6 = vmcs_readl(EXIT_QUALIFICATION);
+ if (!(vcpu->guest_debug &
+ (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))) {
+ vcpu->arch.dr6 = dr6 | DR6_FIXED_1;
+ kvm_queue_exception(vcpu, DB_VECTOR);
+ return 1;
+ }
+ kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1;
+ kvm_run->debug.arch.dr7 = vmcs_readl(GUEST_DR7);
+ /* fall through */
+ case BP_VECTOR:
kvm_run->exit_reason = KVM_EXIT_DEBUG;
kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
kvm_run->debug.arch.exception = ex_no;
- } else {
+ break;
+ default:
kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
kvm_run->ex.exception = ex_no;
kvm_run->ex.error_code = error_code;
+ break;
}
return 0;
}
@@ -2425,21 +2438,44 @@ static int handle_dr(struct kvm_vcpu *vc
unsigned long val;
int dr, reg;
- /*
- * FIXME: this code assumes the host is debugging the guest.
- * need to deal with guest debugging itself too.
- */
+ dr = vmcs_readl(GUEST_DR7);
+ if (dr & DR7_GD) {
+ /*
+ * As the vm-exit takes precedence over the debug trap, we
+ * need to emulate the latter, either for the host or the
+ * guest debugging itself.
+ */
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
+ kvm_run->debug.arch.dr6 = vcpu->arch.dr6;
+ kvm_run->debug.arch.dr7 = dr;
+ kvm_run->debug.arch.pc =
+ vmcs_readl(GUEST_CS_BASE) +
+ vmcs_readl(GUEST_RIP);
+ kvm_run->debug.arch.exception = DB_VECTOR;
+ kvm_run->exit_reason = KVM_EXIT_DEBUG;
+ return 0;
+ } else {
+ vcpu->arch.dr7 &= ~DR7_GD;
+ vcpu->arch.dr6 |= DR6_BD;
+ vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
+ kvm_queue_exception(vcpu, DB_VECTOR);
+ return 1;
+ }
+ }
+
exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
- dr = exit_qualification & 7;
- reg = (exit_qualification >> 8) & 15;
- if (exit_qualification & 16) {
- /* mov from dr */
+ dr = exit_qualification & DEBUG_REG_ACCESS_NUM;
+ reg = DEBUG_REG_ACCESS_REG(exit_qualification);
+ if (exit_qualification & TYPE_MOV_FROM_DR) {
switch (dr) {
+ case 0 ... 3:
+ val = vcpu->arch.db[dr];
+ break;
case 6:
- val = 0xffff0ff0;
+ val = vcpu->arch.dr6;
break;
case 7:
- val = 0x400;
+ val = vcpu->arch.dr7;
break;
default:
val = 0;
@@ -2447,7 +2483,38 @@ static int handle_dr(struct kvm_vcpu *vc
kvm_register_write(vcpu, reg, val);
KVMTRACE_2D(DR_READ, vcpu, (u32)dr, (u32)val, handler);
} else {
- /* mov to dr */
+ val = vcpu->arch.regs[reg];
+ switch (dr) {
+ case 0 ... 3:
+ vcpu->arch.db[dr] = val;
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ vcpu->arch.eff_db[dr] = val;
+ break;
+ case 4 ... 5:
+ if (vcpu->arch.cr4 & X86_CR4_DE)
+ kvm_queue_exception(vcpu, UD_VECTOR);
+ break;
+ case 6:
+ if (val & 0xffffffff00000000ULL) {
+ kvm_queue_exception(vcpu, GP_VECTOR);
+ break;
+ }
+ vcpu->arch.dr6 = (val & DR6_VOLATILE) | DR6_FIXED_1;
+ break;
+ case 7:
+ if (val & 0xffffffff00000000ULL) {
+ kvm_queue_exception(vcpu, GP_VECTOR);
+ break;
+ }
+ vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
+ vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
+ vcpu->arch.switch_db_regs =
+ (val & DR7_BP_EN_MASK);
+ }
+ break;
+ }
+ KVMTRACE_2D(DR_WRITE, vcpu, (u32)dr, (u32)val, handler);
}
skip_emulated_instruction(vcpu);
return 1;
@@ -2579,7 +2646,18 @@ static int handle_task_switch(struct kvm
reason = (u32)exit_qualification >> 30;
tss_selector = exit_qualification;
- return kvm_task_switch(vcpu, tss_selector, reason);
+ if (!kvm_task_switch(vcpu, tss_selector, reason))
+ return 0;
+
+ /* clear all local breakpoint enable flags */
+ vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~55);
+
+ /*
+ * TODO: What about debug traps on tss switch?
+ * Are we supposed to inject them and update dr6?
+ */
+
+ return 1;
}
static int handle_ept_violation(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
@@ -2909,6 +2987,8 @@ static void vmx_vcpu_run(struct kvm_vcpu
*/
vmcs_writel(HOST_CR0, read_cr0());
+ set_debugreg(vcpu->arch.dr6, 6);
+
asm(
/* Store host registers */
#ifdef CONFIG_X86_64
@@ -3027,6 +3107,8 @@ static void vmx_vcpu_run(struct kvm_vcpu
vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
vcpu->arch.regs_dirty = 0;
+ get_debugreg(vcpu->arch.dr6, 6);
+
vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
if (vmx->rmode.irq.pending)
fixup_rmode_irq(vmx);
Index: b/arch/x86/kvm/vmx.h
===================================================================
--- a/arch/x86/kvm/vmx.h
+++ b/arch/x86/kvm/vmx.h
@@ -304,7 +304,7 @@ enum vmcs_field {
#define DEBUG_REG_ACCESS_TYPE 0x10 /* 4, direction of access */
#define TYPE_MOV_TO_DR (0 << 4)
#define TYPE_MOV_FROM_DR (1 << 4)
-#define DEBUG_REG_ACCESS_REG 0xf00 /* 11:8, general purpose reg. */
+#define DEBUG_REG_ACCESS_REG(eq) (((eq) >> 8) & 0xf) /* 11:8, general purpose reg. */
/* segment AR */
Index: b/arch/x86/kvm/x86.c
===================================================================
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2816,7 +2816,7 @@ static int __vcpu_run(struct kvm_vcpu *v
pr_debug("vcpu %d received sipi with vector # %x\n",
vcpu->vcpu_id, vcpu->arch.sipi_vector);
kvm_lapic_reset(vcpu);
- r = kvm_x86_ops->vcpu_reset(vcpu);
+ r = kvm_arch_vcpu_reset(vcpu);
if (r)
return r;
vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
@@ -2899,9 +2899,34 @@ again:
kvm_guest_enter();
+ get_debugreg(vcpu->arch.host_dr6, 6);
+ get_debugreg(vcpu->arch.host_dr7, 7);
+ if (unlikely(vcpu->arch.switch_db_regs)) {
+ get_debugreg(vcpu->arch.host_db[0], 0);
+ get_debugreg(vcpu->arch.host_db[1], 1);
+ get_debugreg(vcpu->arch.host_db[2], 2);
+ get_debugreg(vcpu->arch.host_db[3], 3);
+
+ set_debugreg(0, 7);
+ set_debugreg(vcpu->arch.eff_db[0], 0);
+ set_debugreg(vcpu->arch.eff_db[1], 1);
+ set_debugreg(vcpu->arch.eff_db[2], 2);
+ set_debugreg(vcpu->arch.eff_db[3], 3);
+ }
+
KVMTRACE_0D(VMENTRY, vcpu, entryexit);
kvm_x86_ops->run(vcpu, kvm_run);
+ if (unlikely(vcpu->arch.switch_db_regs)) {
+ set_debugreg(0, 7);
+ set_debugreg(vcpu->arch.host_db[0], 0);
+ set_debugreg(vcpu->arch.host_db[1], 1);
+ set_debugreg(vcpu->arch.host_db[2], 2);
+ set_debugreg(vcpu->arch.host_db[3], 3);
+ }
+ set_debugreg(vcpu->arch.host_dr6, 6);
+ set_debugreg(vcpu->arch.host_dr7, 7);
+
vcpu->guest_mode = 0;
local_irq_enable();
@@ -3860,6 +3885,11 @@ void kvm_arch_vcpu_destroy(struct kvm_vc
int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
{
+ vcpu->arch.switch_db_regs = 0;
+ memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
+ vcpu->arch.dr6 = DR6_FIXED_1;
+ vcpu->arch.dr7 = DR7_FIXED_1;
+
return kvm_x86_ops->vcpu_reset(vcpu);
}
Index: b/include/asm-x86/kvm_host.h
===================================================================
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -128,6 +128,19 @@ enum {
#define KVM_NR_MEM_OBJS 40
+#define KVM_NR_DB_REGS 4
+
+#define DR6_BD (1 << 13)
+#define DR6_BS (1 << 14)
+#define DR6_FIXED_1 0xffff0ff0
+#define DR6_VOLATILE 0x0000e00f
+
+#define DR7_BP_EN_MASK 0x000000ff
+#define DR7_GE (1 << 9)
+#define DR7_GD (1 << 13)
+#define DR7_FIXED_1 0x00000400
+#define DR7_VOLATILE 0xffff23ff
+
/*
* We don't want allocation failures within the mmu code, so we preallocate
* enough memory for a single page fault in a cache.
@@ -296,6 +309,15 @@ struct kvm_vcpu_arch {
bool nmi_pending;
u64 mtrr[0x100];
+
+ int switch_db_regs;
+ unsigned long host_db[KVM_NR_DB_REGS];
+ unsigned long host_dr6;
+ unsigned long host_dr7;
+ unsigned long db[KVM_NR_DB_REGS];
+ unsigned long dr6;
+ unsigned long dr7;
+ unsigned long eff_db[KVM_NR_DB_REGS];
};
struct kvm_mem_alias {
^ permalink raw reply [flat|nested] 17+ messages in thread