From 1261bfa326f5e903166498628a1894edce0caabc Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Thu, 13 Jul 2017 18:30:40 -0700 Subject: [PATCH] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch adds the L1 guest async page fault #PF vmexit handler, such by L1 similar to ordinary async page fault. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li [Passed insn parameters to kvm_mmu_page_fault().] Signed-off-by: Radim Krčmář --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/mmu.c | 33 ++++++++++++++++++++++++++++++ arch/x86/kvm/mmu.h | 3 +++ arch/x86/kvm/svm.c | 36 ++++++--------------------------- arch/x86/kvm/vmx.c | 15 +++++++------- 5 files changed, 51 insertions(+), 37 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8d11ddcb0dbf..4f20ee6c79a1 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -650,6 +650,7 @@ struct kvm_vcpu_arch { u64 msr_val; u32 id; bool send_user_only; + u32 host_apf_reason; } apf; /* OSVW MSRs (AMD only) */ diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index aafd399cf8c6..3825a35cd752 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -46,6 +46,7 @@ #include #include #include +#include "trace.h" /* * When setting this variable to true it enables Two-Dimensional-Paging @@ -3780,6 +3781,38 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, return false; } +int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, + u64 fault_address, char *insn, int insn_len, + bool need_unprotect) +{ + int r = 1; + + switch (vcpu->arch.apf.host_apf_reason) { + default: + trace_kvm_page_fault(fault_address, error_code); + + if (need_unprotect && kvm_event_needs_reinjection(vcpu)) + kvm_mmu_unprotect_page_virt(vcpu, fault_address); + r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn, + insn_len); + break; + case KVM_PV_REASON_PAGE_NOT_PRESENT: + vcpu->arch.apf.host_apf_reason = 0; + local_irq_disable(); + kvm_async_pf_task_wait(fault_address); + local_irq_enable(); + break; + case KVM_PV_REASON_PAGE_READY: + vcpu->arch.apf.host_apf_reason = 0; + local_irq_disable(); + kvm_async_pf_task_wake(fault_address); + local_irq_enable(); + break; + } + return r; +} +EXPORT_SYMBOL_GPL(kvm_handle_page_fault); + static bool check_hugepage_cache_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int level) { diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index a276834950c1..d7d248a000dd 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -77,6 +77,9 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu); void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, bool accessed_dirty); bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu); +int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, + u64 fault_address, char *insn, int insn_len, + bool need_unprotect); static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm) { diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index cde756a02b1a..fb23497cf915 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -194,7 +194,6 @@ struct vcpu_svm { unsigned int3_injected; unsigned long int3_rip; - u32 apf_reason; /* cached guest cpuid flags for faster access */ bool nrips_enabled : 1; @@ -2122,34 +2121,11 @@ static void svm_set_dr7(struct kvm_vcpu *vcpu, unsigned long value) static int pf_interception(struct vcpu_svm *svm) { u64 fault_address = svm->vmcb->control.exit_info_2; - u64 error_code; - int r = 1; + u64 error_code = svm->vmcb->control.exit_info_1; - switch (svm->apf_reason) { - default: - error_code = svm->vmcb->control.exit_info_1; - - 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, + return kvm_handle_page_fault(&svm->vcpu, error_code, fault_address, svm->vmcb->control.insn_bytes, - svm->vmcb->control.insn_len); - break; - case KVM_PV_REASON_PAGE_NOT_PRESENT: - svm->apf_reason = 0; - local_irq_disable(); - kvm_async_pf_task_wait(fault_address); - local_irq_enable(); - break; - case KVM_PV_REASON_PAGE_READY: - svm->apf_reason = 0; - local_irq_disable(); - kvm_async_pf_task_wake(fault_address); - local_irq_enable(); - break; - } - return r; + svm->vmcb->control.insn_len, !npt_enabled); } static int db_interception(struct vcpu_svm *svm) @@ -2630,7 +2606,7 @@ static int nested_svm_exit_special(struct vcpu_svm *svm) break; case SVM_EXIT_EXCP_BASE + PF_VECTOR: /* When we're shadowing, trap PFs, but not async PF */ - if (!npt_enabled && svm->apf_reason == 0) + if (!npt_enabled && svm->vcpu.arch.apf.host_apf_reason == 0) return NESTED_EXIT_HOST; break; default: @@ -2677,7 +2653,7 @@ static int nested_svm_intercept(struct vcpu_svm *svm) } /* async page fault always cause vmexit */ else if ((exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR) && - svm->apf_reason != 0) + svm->vcpu.arch.apf.host_apf_reason != 0) vmexit = NESTED_EXIT_DONE; break; } @@ -4998,7 +4974,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) /* if exit due to PF check for async PF */ if (svm->vmcb->control.exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR) - svm->apf_reason = kvm_read_and_reset_pf_reason(); + svm->vcpu.arch.apf.host_apf_reason = kvm_read_and_reset_pf_reason(); if (npt_enabled) { vcpu->arch.regs_avail &= ~(1 << VCPU_EXREG_PDPTR); diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 69cc228436ea..c9c46e63f744 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5698,14 +5698,11 @@ static int handle_exception(struct kvm_vcpu *vcpu) } if (is_page_fault(intr_info)) { - /* EPT won't cause page fault directly */ - BUG_ON(enable_ept); cr2 = vmcs_readl(EXIT_QUALIFICATION); - trace_kvm_page_fault(cr2, error_code); - - if (kvm_event_needs_reinjection(vcpu)) - kvm_mmu_unprotect_page_virt(vcpu, cr2); - return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL, 0); + /* EPT won't cause page fault directly */ + WARN_ON_ONCE(!vcpu->arch.apf.host_apf_reason && enable_ept); + return kvm_handle_page_fault(vcpu, error_code, cr2, NULL, 0, + true); } ex_no = intr_info & INTR_INFO_VECTOR_MASK; @@ -8643,6 +8640,10 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx) exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO); vmx->exit_intr_info = exit_intr_info; + /* if exit due to PF check for async PF */ + if (is_page_fault(exit_intr_info)) + vmx->vcpu.arch.apf.host_apf_reason = kvm_read_and_reset_pf_reason(); + /* Handle machine checks before interrupts are enabled */ if (basic_exit_reason == EXIT_REASON_MCE_DURING_VMENTRY || is_machine_check(exit_intr_info))