From dc25e89e07d5ef31c476117d2c76b34dbb22196c Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 21 Dec 2010 11:12:07 +0100 Subject: [PATCH] KVM: SVM: copy instruction bytes from VMCB In case of a nested page fault or an intercepted #PF newer SVM implementations provide a copy of the faulting instruction bytes in the VMCB. Use these bytes to feed the instruction emulator and avoid the costly guest instruction fetch in this case. Signed-off-by: Andre Przywara Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/kvm_emulate.h | 2 +- arch/x86/include/asm/kvm_host.h | 9 +++++---- arch/x86/include/asm/svm.h | 4 +++- arch/x86/kvm/emulate.c | 7 +++++-- arch/x86/kvm/mmu.c | 5 +++-- arch/x86/kvm/svm.c | 4 +++- arch/x86/kvm/vmx.c | 4 ++-- arch/x86/kvm/x86.c | 6 ++++-- 8 files changed, 26 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index bf70ecea3974..8e37deb1eb38 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -265,7 +265,7 @@ struct x86_emulate_ctxt { #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 #endif -int x86_decode_insn(struct x86_emulate_ctxt *ctxt); +int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len); #define EMULATION_FAILED -1 #define EMULATION_OK 0 #define EMULATION_RESTART 1 diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index de00b6026b76..6268f6ce6434 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -634,13 +634,13 @@ enum emulation_result { #define EMULTYPE_NO_DECODE (1 << 0) #define EMULTYPE_TRAP_UD (1 << 1) #define EMULTYPE_SKIP (1 << 2) -int x86_emulate_instruction(struct kvm_vcpu *vcpu, - unsigned long cr2, int emulation_type); +int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2, + int emulation_type, void *insn, int insn_len); static inline int emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type) { - return x86_emulate_instruction(vcpu, 0, emulation_type); + return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0); } void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address); @@ -721,7 +721,8 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu); int kvm_fix_hypercall(struct kvm_vcpu *vcpu); -int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code); +int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code, + void *insn, int insn_len); void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva); void kvm_enable_tdp(void); diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h index f0ffb8184089..f2b83bc7d784 100644 --- a/arch/x86/include/asm/svm.h +++ b/arch/x86/include/asm/svm.h @@ -83,7 +83,9 @@ struct __attribute__ ((__packed__)) vmcb_control_area { u32 clean; u32 reserved_5; u64 next_rip; - u8 reserved_6[816]; + u8 insn_len; + u8 insn_bytes[15]; + u8 reserved_6[800]; }; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 36534ecaf596..caf966781d25 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2610,7 +2610,7 @@ done: } int -x86_decode_insn(struct x86_emulate_ctxt *ctxt) +x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) { struct x86_emulate_ops *ops = ctxt->ops; struct decode_cache *c = &ctxt->decode; @@ -2621,7 +2621,10 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt) struct operand memop = { .type = OP_NONE }; c->eip = ctxt->eip; - c->fetch.start = c->fetch.end = c->eip; + c->fetch.start = c->eip; + c->fetch.end = c->fetch.start + insn_len; + if (insn_len > 0) + memcpy(c->fetch.data, insn, insn_len); ctxt->cs_base = seg_base(ctxt, ops, VCPU_SREG_CS); switch (mode) { diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 01c5a104031f..ea6063d9242e 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3330,7 +3330,8 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) } } -int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code) +int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code, + void *insn, int insn_len) { int r; enum emulation_result er; @@ -3348,7 +3349,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code) if (r) goto out; - er = x86_emulate_instruction(vcpu, cr2, 0); + er = x86_emulate_instruction(vcpu, cr2, 0, insn, insn_len); switch (er) { case EMULATE_DONE: diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index a04c01e324b4..af4b911a8bed 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1527,7 +1527,9 @@ static int pf_interception(struct vcpu_svm *svm) trace_kvm_page_fault(fault_address, error_code); if (!npt_enabled && kvm_event_needs_reinjection(&svm->vcpu)) kvm_mmu_unprotect_page_virt(&svm->vcpu, fault_address); - r = kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code); + r = kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code, + svm->vmcb->control.insn_bytes, + svm->vmcb->control.insn_len); break; case KVM_PV_REASON_PAGE_NOT_PRESENT: svm->apf_reason = 0; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index f3c60fb8d95e..736f83955ce9 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3055,7 +3055,7 @@ static int handle_exception(struct kvm_vcpu *vcpu) if (kvm_event_needs_reinjection(vcpu)) kvm_mmu_unprotect_page_virt(vcpu, cr2); - return kvm_mmu_page_fault(vcpu, cr2, error_code); + return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL, 0); } if (vmx->rmode.vm86_active && @@ -3502,7 +3502,7 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS); trace_kvm_page_fault(gpa, exit_qualification); - return kvm_mmu_page_fault(vcpu, gpa, exit_qualification & 0x3); + return kvm_mmu_page_fault(vcpu, gpa, exit_qualification & 0x3, NULL, 0); } static u64 ept_rsvd_mask(u64 spte, int level) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a6fcb76196b7..7ad9cda8ff36 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4365,7 +4365,9 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva) int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2, - int emulation_type) + int emulation_type, + void *insn, + int insn_len) { int r; struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode; @@ -4386,7 +4388,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, vcpu->arch.emulate_ctxt.have_exception = false; vcpu->arch.emulate_ctxt.perm_ok = false; - r = x86_decode_insn(&vcpu->arch.emulate_ctxt); + r = x86_decode_insn(&vcpu->arch.emulate_ctxt, insn, insn_len); if (r == X86EMUL_PROPAGATE_FAULT) goto done;