diff options
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 47 |
1 files changed, 38 insertions, 9 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1d5a7f41879..3416a347384 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4420,6 +4420,7 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu) vcpu->arch.emulate_ctxt.guest_mode = is_guest_mode(vcpu); memset(c, 0, sizeof(struct decode_cache)); memcpy(c->regs, vcpu->arch.regs, sizeof c->regs); + vcpu->arch.emulate_regs_need_sync_from_vcpu = false; } int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq) @@ -4502,6 +4503,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, { int r; struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode; + bool writeback = true; kvm_clear_exception_queue(vcpu); vcpu->arch.mmio_fault_cr2 = cr2; @@ -4542,9 +4544,12 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, return EMULATE_DONE; } - /* this is needed for vmware backdor interface to work since it + /* this is needed for vmware backdoor interface to work since it changes registers values during IO operation */ - memcpy(c->regs, vcpu->arch.regs, sizeof c->regs); + if (vcpu->arch.emulate_regs_need_sync_from_vcpu) { + vcpu->arch.emulate_regs_need_sync_from_vcpu = false; + memcpy(c->regs, vcpu->arch.regs, sizeof c->regs); + } restart: r = x86_emulate_insn(&vcpu->arch.emulate_ctxt); @@ -4565,19 +4570,28 @@ restart: } else if (vcpu->arch.pio.count) { if (!vcpu->arch.pio.in) vcpu->arch.pio.count = 0; + else + writeback = false; r = EMULATE_DO_MMIO; - } else if (vcpu->mmio_needed) + } else if (vcpu->mmio_needed) { + if (!vcpu->mmio_is_write) + writeback = false; r = EMULATE_DO_MMIO; - else if (r == EMULATION_RESTART) + } else if (r == EMULATION_RESTART) goto restart; else r = EMULATE_DONE; - toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility); - kvm_set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); - kvm_make_request(KVM_REQ_EVENT, vcpu); - memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); - kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip); + if (writeback) { + toggle_interruptibility(vcpu, + vcpu->arch.emulate_ctxt.interruptibility); + kvm_set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); + kvm_make_request(KVM_REQ_EVENT, vcpu); + memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); + vcpu->arch.emulate_regs_need_sync_to_vcpu = false; + kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip); + } else + vcpu->arch.emulate_regs_need_sync_to_vcpu = true; return r; } @@ -5587,6 +5601,18 @@ out: int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) { + if (vcpu->arch.emulate_regs_need_sync_to_vcpu) { + /* + * We are here if userspace calls get_regs() in the middle of + * instruction emulation. Registers state needs to be copied + * back from emulation context to vcpu. Usrapace shouldn't do + * that usually, but some bad designed PV devices (vmware + * backdoor interface) need this to work + */ + struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode; + memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); + vcpu->arch.emulate_regs_need_sync_to_vcpu = false; + } regs->rax = kvm_register_read(vcpu, VCPU_REGS_RAX); regs->rbx = kvm_register_read(vcpu, VCPU_REGS_RBX); regs->rcx = kvm_register_read(vcpu, VCPU_REGS_RCX); @@ -5614,6 +5640,9 @@ int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) { + vcpu->arch.emulate_regs_need_sync_from_vcpu = true; + vcpu->arch.emulate_regs_need_sync_to_vcpu = false; + kvm_register_write(vcpu, VCPU_REGS_RAX, regs->rax); kvm_register_write(vcpu, VCPU_REGS_RBX, regs->rbx); kvm_register_write(vcpu, VCPU_REGS_RCX, regs->rcx); |