From: Nicholas Piggin <npiggin@gmail.com>
To: kvm-ppc@vger.kernel.org
Cc: Fabiano Rosas <farosas@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org,
Nicholas Piggin <npiggin@gmail.com>,
Daniel Axtens <dja@axtens.net>
Subject: [PATCH v3 10/41] KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM
Date: Sat, 6 Mar 2021 01:06:07 +1000 [thread overview]
Message-ID: <20210305150638.2675513-11-npiggin@gmail.com> (raw)
In-Reply-To: <20210305150638.2675513-1-npiggin@gmail.com>
Move the GUEST_MODE_SKIP logic into KVM code. This is quite a KVM
internal detail that has no real need to be in common handlers.
Also add a comment explaining why this thing exists.
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/exceptions-64s.S | 60 ----------------------------
arch/powerpc/kvm/book3s_64_entry.S | 51 ++++++++++++++++++++++-
2 files changed, 50 insertions(+), 61 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index ba13d749d203..d956dd9ed61f 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -133,7 +133,6 @@ name:
#define IBRANCH_TO_COMMON .L_IBRANCH_TO_COMMON_\name\() /* ENTRY branch to common */
#define IREALMODE_COMMON .L_IREALMODE_COMMON_\name\() /* Common runs in realmode */
#define IMASK .L_IMASK_\name\() /* IRQ soft-mask bit */
-#define IKVM_SKIP .L_IKVM_SKIP_\name\() /* Generate KVM skip handler */
#define IKVM_REAL .L_IKVM_REAL_\name\() /* Real entry tests KVM */
#define __IKVM_REAL(name) .L_IKVM_REAL_ ## name
#define IKVM_VIRT .L_IKVM_VIRT_\name\() /* Virt entry tests KVM */
@@ -190,9 +189,6 @@ do_define_int n
.ifndef IMASK
IMASK=0
.endif
- .ifndef IKVM_SKIP
- IKVM_SKIP=0
- .endif
.ifndef IKVM_REAL
IKVM_REAL=0
.endif
@@ -250,15 +246,10 @@ do_define_int n
.balign IFETCH_ALIGN_BYTES
\name\()_kvm:
- .if IKVM_SKIP
- cmpwi r10,KVM_GUEST_MODE_SKIP
- beq 89f
- .else
BEGIN_FTR_SECTION
ld r10,IAREA+EX_CFAR(r13)
std r10,HSTATE_CFAR(r13)
END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
- .endif
ld r10,IAREA+EX_CTR(r13)
mtctr r10
@@ -285,27 +276,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ori r12,r12,(IVEC)
.endif
b kvmppc_interrupt
-
- .if IKVM_SKIP
-89: mtocrf 0x80,r9
- ld r10,IAREA+EX_CTR(r13)
- mtctr r10
- ld r9,IAREA+EX_R9(r13)
- ld r10,IAREA+EX_R10(r13)
- ld r11,IAREA+EX_R11(r13)
- ld r12,IAREA+EX_R12(r13)
- .if IHSRR_IF_HVMODE
- BEGIN_FTR_SECTION
- b kvmppc_skip_Hinterrupt
- FTR_SECTION_ELSE
- b kvmppc_skip_interrupt
- ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
- .elseif IHSRR
- b kvmppc_skip_Hinterrupt
- .else
- b kvmppc_skip_interrupt
- .endif
- .endif
.endm
#else
@@ -1083,7 +1053,6 @@ INT_DEFINE_BEGIN(machine_check)
ISET_RI=0
IDAR=1
IDSISR=1
- IKVM_SKIP=1
IKVM_REAL=1
INT_DEFINE_END(machine_check)
@@ -1356,7 +1325,6 @@ INT_DEFINE_BEGIN(data_access)
IVEC=0x300
IDAR=1
IDSISR=1
- IKVM_SKIP=1
IKVM_REAL=1
INT_DEFINE_END(data_access)
@@ -1410,7 +1378,6 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
INT_DEFINE_BEGIN(data_access_slb)
IVEC=0x380
IDAR=1
- IKVM_SKIP=1
IKVM_REAL=1
INT_DEFINE_END(data_access_slb)
@@ -2080,7 +2047,6 @@ INT_DEFINE_BEGIN(h_data_storage)
IHSRR=1
IDAR=1
IDSISR=1
- IKVM_SKIP=1
IKVM_REAL=1
IKVM_VIRT=1
INT_DEFINE_END(h_data_storage)
@@ -3024,32 +2990,6 @@ EXPORT_SYMBOL(do_uaccess_flush)
MASKED_INTERRUPT
MASKED_INTERRUPT hsrr=1
-#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
-kvmppc_skip_interrupt:
- /*
- * Here all GPRs are unchanged from when the interrupt happened
- * except for r13, which is saved in SPRG_SCRATCH0.
- */
- mfspr r13, SPRN_SRR0
- addi r13, r13, 4
- mtspr SPRN_SRR0, r13
- GET_SCRATCH0(r13)
- RFI_TO_KERNEL
- b .
-
-kvmppc_skip_Hinterrupt:
- /*
- * Here all GPRs are unchanged from when the interrupt happened
- * except for r13, which is saved in SPRG_SCRATCH0.
- */
- mfspr r13, SPRN_HSRR0
- addi r13, r13, 4
- mtspr SPRN_HSRR0, r13
- GET_SCRATCH0(r13)
- HRFI_TO_KERNEL
- b .
-#endif
-
/*
* Relocation-on interrupts: A subset of the interrupts can be delivered
* with IR=1/DR=1, if AIL==2 and MSR.HV won't be changed by delivering
diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S
index 7a039ea78f15..a5412e24cc05 100644
--- a/arch/powerpc/kvm/book3s_64_entry.S
+++ b/arch/powerpc/kvm/book3s_64_entry.S
@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#include <asm/asm-offsets.h>
#include <asm/cache.h>
+#include <asm/exception-64s.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_book3s_asm.h>
#include <asm/ppc_asm.h>
@@ -20,9 +21,12 @@ kvmppc_interrupt:
* guest R12 saved in shadow VCPU SCRATCH0
* guest R13 saved in SPRN_SCRATCH0
*/
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
std r9,HSTATE_SCRATCH2(r13)
lbz r9,HSTATE_IN_GUEST(r13)
+ cmpwi r9,KVM_GUEST_MODE_SKIP
+ beq- .Lmaybe_skip
+.Lno_skip:
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
cmpwi r9,KVM_GUEST_MODE_HOST_HV
beq kvmppc_bad_host_intr
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
@@ -34,3 +38,48 @@ kvmppc_interrupt:
#else
b kvmppc_interrupt_pr
#endif
+
+/*
+ * KVM uses a trick where it is running in MSR[HV]=1 mode in real-mode with the
+ * guest MMU context loaded, and it sets KVM_GUEST_MODE_SKIP and enables
+ * MSR[DR]=1 while leaving MSR[IR]=0, so it continues to fetch HV instructions
+ * but loads and stores will access the guest context. This is used to load
+ * the faulting instruction without walking page tables.
+ *
+ * However the guest context may not be able to translate, or it may cause a
+ * machine check or other issue, which will result in a fault in the host
+ * (even with KVM-HV).
+ *
+ * These faults are caught here and if the fault was (or was likely) due to
+ * that load, then we just return with the PC advanced +4 and skip the load,
+ * which then goes to the slow path and walks the page tables.
+ */
+.Lmaybe_skip:
+ cmpwi r12,BOOK3S_INTERRUPT_MACHINE_CHECK
+ beq 1f
+ cmpwi r12,BOOK3S_INTERRUPT_DATA_STORAGE
+ beq 1f
+ cmpwi r12,BOOK3S_INTERRUPT_DATA_SEGMENT
+ beq 1f
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ /* HSRR interrupts have 2 added to trap vector */
+ cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE | 0x2
+ beq 2f
+#endif
+ b .Lno_skip
+1: mfspr r9,SPRN_SRR0
+ addi r9,r9,4
+ mtspr SPRN_SRR0,r9
+ ld r12,HSTATE_SCRATCH0(r13)
+ ld r9,HSTATE_SCRATCH2(r13)
+ GET_SCRATCH0(r13)
+ RFI_TO_KERNEL
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+2: mfspr r9,SPRN_HSRR0
+ addi r9,r9,4
+ mtspr SPRN_HSRR0,r9
+ ld r12,HSTATE_SCRATCH0(r13)
+ ld r9,HSTATE_SCRATCH2(r13)
+ GET_SCRATCH0(r13)
+ HRFI_TO_KERNEL
+#endif
--
2.23.0
next prev parent reply other threads:[~2021-03-05 15:11 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-05 15:05 [PATCH v3 00/41] KVM: PPC: Book3S: C-ify the P9 entry/exit code Nicholas Piggin
2021-03-05 15:05 ` [PATCH v3 01/41] KVM: PPC: Book3S HV: Disallow LPCR[AIL] to be set to 1 or 2 Nicholas Piggin
2021-03-08 15:26 ` Fabiano Rosas
2021-03-09 1:11 ` Nicholas Piggin
2021-03-05 15:05 ` [PATCH v3 02/41] KVM: PPC: Book3S HV: Prevent radix guests from setting LPCR[TC] Nicholas Piggin
2021-03-08 15:47 ` Fabiano Rosas
2021-03-09 1:14 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 03/41] KVM: PPC: Book3S HV: Remove redundant mtspr PSPB Nicholas Piggin
2021-03-12 5:07 ` Daniel Axtens
2021-03-05 15:06 ` [PATCH v3 04/41] KVM: PPC: Book3S HV: remove unused kvmppc_h_protect argument Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 05/41] KVM: PPC: Book3S HV: Fix CONFIG_SPAPR_TCE_IOMMU=n default hcalls Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 06/41] powerpc/64s: Remove KVM handler support from CBE_RAS interrupts Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 07/41] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 08/41] KVM: PPC: Book3S HV: Ensure MSR[ME] is always set in guest MSR Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 09/41] KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Nicholas Piggin
2021-03-05 15:06 ` Nicholas Piggin [this message]
2021-03-05 15:06 ` [PATCH v3 11/41] KVM: PPC: Book3S 64: add hcall interrupt handler Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 12/41] KVM: PPC: Book3S 64: Move hcall early register setup to KVM Nicholas Piggin
2021-03-12 5:45 ` Daniel Axtens
2021-03-16 3:43 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 13/41] KVM: PPC: Book3S 64: Move interrupt " Nicholas Piggin
2021-03-20 7:19 ` Alexey Kardashevskiy
2021-03-05 15:06 ` [PATCH v3 14/41] KVM: PPC: Book3S 64: move bad_host_intr check to HV handler Nicholas Piggin
2021-03-20 9:07 ` Alexey Kardashevskiy
2021-03-22 3:18 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 15/41] KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences Nicholas Piggin
2021-03-22 2:09 ` Alexey Kardashevskiy
2021-03-22 4:06 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 16/41] KVM: PPC: Book3S HV P9: Move radix MMU switching instructions together Nicholas Piggin
2021-03-22 4:24 ` Alexey Kardashevskiy
2021-03-22 5:25 ` Nicholas Piggin
2021-03-22 6:21 ` Alexey Kardashevskiy
2021-03-05 15:06 ` [PATCH v3 17/41] KVM: PPC: Book3S HV P9: implement kvmppc_xive_pull_vcpu in C Nicholas Piggin
2021-03-22 5:05 ` Alexey Kardashevskiy
2021-03-22 16:19 ` Cédric Le Goater
2021-03-22 18:13 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 18/41] KVM: PPC: Book3S HV P9: Move xive vcpu context management into kvmhv_p9_guest_entry Nicholas Piggin
2021-03-22 5:30 ` Alexey Kardashevskiy
2021-03-05 15:06 ` [PATCH v3 19/41] KVM: PPC: Book3S HV P9: Stop handling hcalls in real-mode in the P9 path Nicholas Piggin
2021-03-17 16:22 ` Fabiano Rosas
2021-03-17 22:41 ` Nicholas Piggin
2021-03-22 16:12 ` Cédric Le Goater
2021-03-22 7:30 ` Alexey Kardashevskiy
2021-03-22 13:15 ` Nicholas Piggin
2021-03-22 16:01 ` Cédric Le Goater
2021-03-22 18:22 ` Nicholas Piggin
2021-03-23 7:26 ` Cédric Le Goater
2021-03-05 15:06 ` [PATCH v3 20/41] KVM: PPC: Book3S HV P9: Move setting HDEC after switching to guest LPCR Nicholas Piggin
2021-03-08 17:52 ` Fabiano Rosas
2021-03-22 8:39 ` Alexey Kardashevskiy
2021-03-22 13:24 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 21/41] KVM: PPC: Book3S HV P9: Use large decrementer for HDEC Nicholas Piggin
2021-03-22 7:58 ` Alexey Kardashevskiy
2021-03-05 15:06 ` [PATCH v3 22/41] KVM: PPC: Book3S HV P9: Use host timer accounting to avoid decrementer read Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 23/41] KVM: PPC: Book3S HV P9: Reduce mftb per guest entry/exit Nicholas Piggin
2021-03-12 12:55 ` Fabiano Rosas
2021-03-05 15:06 ` [PATCH v3 24/41] powerpc: add set_dec_or_work API for safely updating decrementer Nicholas Piggin
2021-03-22 9:38 ` Alexey Kardashevskiy
2021-03-05 15:06 ` [PATCH v3 25/41] KVM: PPC: Book3S HV P9: Reduce irq_work vs guest decrementer races Nicholas Piggin
2021-03-23 1:43 ` Alexey Kardashevskiy
2021-03-05 15:06 ` [PATCH v3 26/41] KVM: PPC: Book3S HV P9: Implement the rest of the P9 path in C Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 27/41] KVM: PPC: Book3S HV P9: inline kvmhv_load_hv_regs_and_go into __kvmhv_vcpu_entry_p9 Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 28/41] KVM: PPC: Book3S HV P9: Read machine check registers while MSR[RI] is 0 Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 29/41] KVM: PPC: Book3S HV P9: Improve exit timing accounting coverage Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 30/41] KVM: PPC: Book3S HV P9: Move SPR loading after expiry time check Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 31/41] KVM: PPC: Book3S HV P9: Add helpers for OS SPR handling Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 32/41] KVM: PPC: Book3S HV P9: Switch to guest MMU context as late as possible Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 33/41] KVM: PPC: Book3S HV: Implement radix prefetch workaround by disabling MMU Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 34/41] KVM: PPC: Book3S HV: Remove support for dependent threads mode on P9 Nicholas Piggin
2021-03-17 15:11 ` Aneesh Kumar K.V
2021-03-22 3:27 ` Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 35/41] KVM: PPC: Book3S HV: Remove radix guest support from P7/8 path Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 36/41] KVM: PPC: Book3S HV P9: Allow all P9 processors to enable nested HV Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 37/41] KVM: PPC: Book3S HV: small pseries_do_hcall cleanup Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 38/41] KVM: PPC: Book3S HV: add virtual mode handlers for HPT hcalls and page faults Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 39/41] KVM: PPC: Book3S HV P9: implement hash guest support Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 40/41] KVM: PPC: Book3S HV P9: implement hash host / " Nicholas Piggin
2021-03-05 15:06 ` [PATCH v3 41/41] KVM: PPC: Book3S HV: remove ISA v3.0 and v3.1 support from P7/8 path Nicholas Piggin
2021-03-16 6:06 ` [PATCH v3 00/41] KVM: PPC: Book3S: C-ify the P9 entry/exit code Nicholas Piggin
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