diff options
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/include/asm/kvm_host.h | 3 | ||||
-rw-r--r-- | arch/x86/kvm/emulate.c | 18 | ||||
-rw-r--r-- | arch/x86/kvm/x86.c | 120 |
3 files changed, 135 insertions, 6 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 5d4c39c37390..dd2665504dc0 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -961,6 +961,9 @@ struct kvm_arch { bool guest_can_read_msr_platform_info; bool exception_payload_enabled; + /* Deflect RDMSR and WRMSR to user space when they trigger a #GP */ + u32 user_space_msr_mask; + struct kvm_pmu_event_filter *pmu_event_filter; struct task_struct *nx_lpage_recovery_thread; }; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 85111cd0adcd..0cc0db500f71 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3701,11 +3701,18 @@ static int em_dr_write(struct x86_emulate_ctxt *ctxt) static int em_wrmsr(struct x86_emulate_ctxt *ctxt) { + u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX); u64 msr_data; + int r; msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX) | ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32); - if (ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data)) + r = ctxt->ops->set_msr(ctxt, msr_index, msr_data); + + if (r == X86EMUL_IO_NEEDED) + return r; + + if (r) return emulate_gp(ctxt, 0); return X86EMUL_CONTINUE; @@ -3713,9 +3720,16 @@ static int em_wrmsr(struct x86_emulate_ctxt *ctxt) static int em_rdmsr(struct x86_emulate_ctxt *ctxt) { + u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX); u64 msr_data; + int r; + + r = ctxt->ops->get_msr(ctxt, msr_index, &msr_data); + + if (r == X86EMUL_IO_NEEDED) + return r; - if (ctxt->ops->get_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), &msr_data)) + if (r) return emulate_gp(ctxt, 0); *reg_write(ctxt, VCPU_REGS_RAX) = (u32)msr_data; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 43173382f02f..af6d008145cd 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1590,12 +1590,89 @@ int kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data) } EXPORT_SYMBOL_GPL(kvm_set_msr); +static int complete_emulated_msr(struct kvm_vcpu *vcpu, bool is_read) +{ + if (vcpu->run->msr.error) { + kvm_inject_gp(vcpu, 0); + return 1; + } else if (is_read) { + kvm_rax_write(vcpu, (u32)vcpu->run->msr.data); + kvm_rdx_write(vcpu, vcpu->run->msr.data >> 32); + } + + return kvm_skip_emulated_instruction(vcpu); +} + +static int complete_emulated_rdmsr(struct kvm_vcpu *vcpu) +{ + return complete_emulated_msr(vcpu, true); +} + +static int complete_emulated_wrmsr(struct kvm_vcpu *vcpu) +{ + return complete_emulated_msr(vcpu, false); +} + +static u64 kvm_msr_reason(int r) +{ + switch (r) { + case -ENOENT: + return KVM_MSR_EXIT_REASON_UNKNOWN; + default: + return KVM_MSR_EXIT_REASON_INVAL; + } +} + +static int kvm_msr_user_space(struct kvm_vcpu *vcpu, u32 index, + u32 exit_reason, u64 data, + int (*completion)(struct kvm_vcpu *vcpu), + int r) +{ + u64 msr_reason = kvm_msr_reason(r); + + /* Check if the user wanted to know about this MSR fault */ + if (!(vcpu->kvm->arch.user_space_msr_mask & msr_reason)) + return 0; + + vcpu->run->exit_reason = exit_reason; + vcpu->run->msr.error = 0; + memset(vcpu->run->msr.pad, 0, sizeof(vcpu->run->msr.pad)); + vcpu->run->msr.reason = msr_reason; + vcpu->run->msr.index = index; + vcpu->run->msr.data = data; + vcpu->arch.complete_userspace_io = completion; + + return 1; +} + +static int kvm_get_msr_user_space(struct kvm_vcpu *vcpu, u32 index, int r) +{ + return kvm_msr_user_space(vcpu, index, KVM_EXIT_X86_RDMSR, 0, + complete_emulated_rdmsr, r); +} + +static int kvm_set_msr_user_space(struct kvm_vcpu *vcpu, u32 index, u64 data, int r) +{ + return kvm_msr_user_space(vcpu, index, KVM_EXIT_X86_WRMSR, data, + complete_emulated_wrmsr, r); +} + int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu) { u32 ecx = kvm_rcx_read(vcpu); u64 data; + int r; + + r = kvm_get_msr(vcpu, ecx, &data); - if (kvm_get_msr(vcpu, ecx, &data)) { + /* MSR read failed? See if we should ask user space */ + if (r && kvm_get_msr_user_space(vcpu, ecx, r)) { + /* Bounce to user space */ + return 0; + } + + /* MSR read failed? Inject a #GP */ + if (r) { trace_kvm_msr_read_ex(ecx); kvm_inject_gp(vcpu, 0); return 1; @@ -1613,8 +1690,18 @@ int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu) { u32 ecx = kvm_rcx_read(vcpu); u64 data = kvm_read_edx_eax(vcpu); + int r; - if (kvm_set_msr(vcpu, ecx, data)) { + r = kvm_set_msr(vcpu, ecx, data); + + /* MSR write failed? See if we should ask user space */ + if (r && kvm_set_msr_user_space(vcpu, ecx, data, r)) { + /* Bounce to user space */ + return 0; + } + + /* MSR write failed? Inject a #GP */ + if (r) { trace_kvm_msr_write_ex(ecx, data); kvm_inject_gp(vcpu, 0); return 1; @@ -3526,6 +3613,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_EXCEPTION_PAYLOAD: case KVM_CAP_SET_GUEST_DEBUG: case KVM_CAP_LAST_CPU: + case KVM_CAP_X86_USER_SPACE_MSR: r = 1; break; case KVM_CAP_SYNC_REGS: @@ -5046,6 +5134,10 @@ split_irqchip_unlock: kvm->arch.exception_payload_enabled = cap->args[0]; r = 0; break; + case KVM_CAP_X86_USER_SPACE_MSR: + kvm->arch.user_space_msr_mask = cap->args[0]; + r = 0; + break; default: r = -EINVAL; break; @@ -6378,13 +6470,33 @@ static void emulator_set_segment(struct x86_emulate_ctxt *ctxt, u16 selector, static int emulator_get_msr(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata) { - return kvm_get_msr(emul_to_vcpu(ctxt), msr_index, pdata); + struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); + int r; + + r = kvm_get_msr(vcpu, msr_index, pdata); + + if (r && kvm_get_msr_user_space(vcpu, msr_index, r)) { + /* Bounce to user space */ + return X86EMUL_IO_NEEDED; + } + + return r; } static int emulator_set_msr(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data) { - return kvm_set_msr(emul_to_vcpu(ctxt), msr_index, data); + struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); + int r; + + r = kvm_set_msr(vcpu, msr_index, data); + + if (r && kvm_set_msr_user_space(vcpu, msr_index, data, r)) { + /* Bounce to user space */ + return X86EMUL_IO_NEEDED; + } + + return r; } static u64 emulator_get_smbase(struct x86_emulate_ctxt *ctxt) |