diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/svm.c | 17 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 52 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 6 |
3 files changed, 36 insertions, 39 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index cb7ad362e9b9..ce75296b1b10 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -777,14 +777,15 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu) svm->next_rip = svm->vmcb->control.next_rip; } - if (!svm->next_rip) - return kvm_emulate_instruction(vcpu, EMULTYPE_SKIP); - - if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE) - printk(KERN_ERR "%s: ip 0x%lx next 0x%llx\n", - __func__, kvm_rip_read(vcpu), svm->next_rip); - - kvm_rip_write(vcpu, svm->next_rip); + if (!svm->next_rip) { + if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP)) + return 0; + } else { + if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE) + pr_err("%s: ip 0x%lx next 0x%llx\n", + __func__, kvm_rip_read(vcpu), svm->next_rip); + kvm_rip_write(vcpu, svm->next_rip); + } svm_set_interrupt_shadow(vcpu, 0); return 1; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e71dc36850cb..ef98311ad153 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1501,17 +1501,27 @@ static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data) return 0; } -/* - * Returns an int to be compatible with SVM implementation (which can fail). - * Do not use directly, use skip_emulated_instruction() instead. - */ -static int __skip_emulated_instruction(struct kvm_vcpu *vcpu) +static int skip_emulated_instruction(struct kvm_vcpu *vcpu) { unsigned long rip; - rip = kvm_rip_read(vcpu); - rip += vmcs_read32(VM_EXIT_INSTRUCTION_LEN); - kvm_rip_write(vcpu, rip); + /* + * Using VMCS.VM_EXIT_INSTRUCTION_LEN on EPT misconfig depends on + * undefined behavior: Intel's SDM doesn't mandate the VMCS field be + * set when EPT misconfig occurs. In practice, real hardware updates + * VM_EXIT_INSTRUCTION_LEN on EPT misconfig, but other hypervisors + * (namely Hyper-V) don't set it due to it being undefined behavior, + * i.e. we end up advancing IP with some random value. + */ + if (!static_cpu_has(X86_FEATURE_HYPERVISOR) || + to_vmx(vcpu)->exit_reason != EXIT_REASON_EPT_MISCONFIG) { + rip = kvm_rip_read(vcpu); + rip += vmcs_read32(VM_EXIT_INSTRUCTION_LEN); + kvm_rip_write(vcpu, rip); + } else { + if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP)) + return 0; + } /* skipping an emulated instruction also counts */ vmx_set_interrupt_shadow(vcpu, 0); @@ -1519,11 +1529,6 @@ static int __skip_emulated_instruction(struct kvm_vcpu *vcpu) return 1; } -static inline void skip_emulated_instruction(struct kvm_vcpu *vcpu) -{ - (void)__skip_emulated_instruction(vcpu); -} - static void vmx_clear_hlt(struct kvm_vcpu *vcpu) { /* @@ -4587,7 +4592,7 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) vcpu->arch.dr6 &= ~DR_TRAP_BITS; vcpu->arch.dr6 |= dr6 | DR6_RTM; if (is_icebp(intr_info)) - skip_emulated_instruction(vcpu); + WARN_ON(!skip_emulated_instruction(vcpu)); kvm_queue_exception(vcpu, DB_VECTOR); return 1; @@ -5068,7 +5073,7 @@ static int handle_task_switch(struct kvm_vcpu *vcpu) if (!idt_v || (type != INTR_TYPE_HARD_EXCEPTION && type != INTR_TYPE_EXT_INTR && type != INTR_TYPE_NMI_INTR)) - skip_emulated_instruction(vcpu); + WARN_ON(!skip_emulated_instruction(vcpu)); /* * TODO: What about debug traps on tss switch? @@ -5135,20 +5140,7 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu) if (!is_guest_mode(vcpu) && !kvm_io_bus_write(vcpu, KVM_FAST_MMIO_BUS, gpa, 0, NULL)) { trace_kvm_fast_mmio(gpa); - /* - * Doing kvm_skip_emulated_instruction() depends on undefined - * behavior: Intel's manual doesn't mandate - * VM_EXIT_INSTRUCTION_LEN to be set in VMCS when EPT MISCONFIG - * occurs and while on real hardware it was observed to be set, - * other hypervisors (namely Hyper-V) don't set it, we end up - * advancing IP with some random value. Disable fast mmio when - * running nested and keep it for real hardware in hope that - * VM_EXIT_INSTRUCTION_LEN will always be set correctly. - */ - if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) - return kvm_skip_emulated_instruction(vcpu); - else - return kvm_emulate_instruction(vcpu, EMULTYPE_SKIP); + return kvm_skip_emulated_instruction(vcpu); } return kvm_mmu_page_fault(vcpu, gpa, PFERR_RSVD_MASK, NULL, 0); @@ -7722,7 +7714,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { .run = vmx_vcpu_run, .handle_exit = vmx_handle_exit, - .skip_emulated_instruction = __skip_emulated_instruction, + .skip_emulated_instruction = skip_emulated_instruction, .set_interrupt_shadow = vmx_set_interrupt_shadow, .get_interrupt_shadow = vmx_get_interrupt_shadow, .patch_hypercall = vmx_patch_hypercall, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a83b269126a0..c38d247dbffb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6657,11 +6657,15 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, return 1; } + /* + * Note, EMULTYPE_SKIP is intended for use *only* by vendor callbacks + * for kvm_skip_emulated_instruction(). The caller is responsible for + * updating interruptibility state and injecting single-step #DBs. + */ if (emulation_type & EMULTYPE_SKIP) { kvm_rip_write(vcpu, ctxt->_eip); if (ctxt->eflags & X86_EFLAGS_RF) kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF); - kvm_x86_ops->set_interrupt_shadow(vcpu, 0); return 1; } |