From 80ced186d1761d2a66163d9eeb468ddb1f7e0697 Mon Sep 17 00:00:00 2001 From: Mohammed Gamal Date: Tue, 1 Sep 2009 12:48:18 +0200 Subject: [PATCH] KVM: VMX: Enhance invalid guest state emulation - Change returned handle_invalid_guest_state() to return relevant exit codes - Move triggering the emulation from vmx_vcpu_run() to vmx_handle_exit() - Return to userspace instead of repeatedly trying to emulate instructions that have already failed Signed-off-by: Mohammed Gamal Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/vmx.c | 44 ++++++++++++++++++++------------------------ 1 file changed, 20 insertions(+), 24 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 4635298..73cb5dd 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -107,7 +107,6 @@ struct vcpu_vmx { } rmode; int vpid; bool emulation_required; - enum emulation_result invalid_state_emulation_result; /* Support for vnmi-less CPUs */ int soft_vnmi_blocked; @@ -3322,35 +3321,37 @@ static int handle_nmi_window(struct kvm_vcpu *vcpu) return 1; } -static void handle_invalid_guest_state(struct kvm_vcpu *vcpu) +static int handle_invalid_guest_state(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); enum emulation_result err = EMULATE_DONE; - - local_irq_enable(); - preempt_enable(); + int ret = 1; while (!guest_state_valid(vcpu)) { err = emulate_instruction(vcpu, 0, 0, 0); - if (err == EMULATE_DO_MMIO) - break; + if (err == EMULATE_DO_MMIO) { + ret = 0; + goto out; + } if (err != EMULATE_DONE) { kvm_report_emulation_failure(vcpu, "emulation failure"); - break; + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; + ret = 0; + goto out; } if (signal_pending(current)) - break; + goto out; if (need_resched()) schedule(); } - preempt_disable(); - local_irq_disable(); - - vmx->invalid_state_emulation_result = err; + vmx->emulation_required = 0; +out: + return ret; } /* @@ -3406,13 +3407,9 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) trace_kvm_exit(exit_reason, kvm_rip_read(vcpu)); - /* If we need to emulate an MMIO from handle_invalid_guest_state - * we just return 0 */ - if (vmx->emulation_required && emulate_invalid_guest_state) { - if (guest_state_valid(vcpu)) - vmx->emulation_required = 0; - return vmx->invalid_state_emulation_result != EMULATE_DO_MMIO; - } + /* If guest state is invalid, start emulating */ + if (vmx->emulation_required && emulate_invalid_guest_state) + return handle_invalid_guest_state(vcpu); /* Access CR3 don't cause VMExit in paging mode, so we need * to sync with guest real CR3. */ @@ -3607,11 +3604,10 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked)) vmx->entry_time = ktime_get(); - /* Handle invalid guest state instead of entering VMX */ - if (vmx->emulation_required && emulate_invalid_guest_state) { - handle_invalid_guest_state(vcpu); + /* Don't enter VMX if guest state is invalid, let the exit handler + start emulation until we arrive back to a valid state */ + if (vmx->emulation_required && emulate_invalid_guest_state) return; - } if (test_bit(VCPU_REGS_RSP, (unsigned long *)&vcpu->arch.regs_dirty)) vmcs_writel(GUEST_RSP, vcpu->arch.regs[VCPU_REGS_RSP]); -- 2.7.4