From a6c6ed1e81060e110258dbc7118fda07e9971e48 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 27 Aug 2019 14:40:30 -0700 Subject: [PATCH] KVM: x86: Don't attempt VMWare emulation on #GP with non-zero error code The VMware backdoor hooks #GP faults on IN{S}, OUT{S}, and RDPMC, none of which generate a non-zero error code for their #GP. Re-injecting #GP instead of attempting emulation on a non-zero error code will allow a future patch to move #GP injection (for emulation failure) into kvm_emulate_instruction() without having to plumb in the error code. Reviewed-and-tested-by: Vitaly Kuznetsov Reviewed-by: Liran Alon Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 10 +++++++++- arch/x86/kvm/vmx/vmx.c | 12 +++++++++++- 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 7e352e81df31..00ec27bc2946 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2772,12 +2772,20 @@ static int gp_interception(struct vcpu_svm *svm) WARN_ON_ONCE(!enable_vmware_backdoor); + /* + * VMware backdoor emulation on #GP interception only handles IN{S}, + * OUT{S}, and RDPMC, none of which generate a non-zero error code. + */ + if (error_code) { + kvm_queue_exception_e(vcpu, GP_VECTOR, error_code); + return 1; + } er = kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE | EMULTYPE_NO_UD_ON_FAIL); if (er == EMULATE_USER_EXIT) return 0; else if (er != EMULATE_DONE) - kvm_queue_exception_e(vcpu, GP_VECTOR, error_code); + kvm_queue_exception_e(vcpu, GP_VECTOR, 0); return 1; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 8f61250fc1c0..d1bac3cb2440 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4539,12 +4539,22 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) if (!vmx->rmode.vm86_active && is_gp_fault(intr_info)) { WARN_ON_ONCE(!enable_vmware_backdoor); + + /* + * VMware backdoor emulation on #GP interception only handles + * IN{S}, OUT{S}, and RDPMC, none of which generate a non-zero + * error code on #GP. + */ + if (error_code) { + kvm_queue_exception_e(vcpu, GP_VECTOR, error_code); + return 1; + } er = kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE | EMULTYPE_NO_UD_ON_FAIL); if (er == EMULATE_USER_EXIT) return 0; else if (er != EMULATE_DONE) - kvm_queue_exception_e(vcpu, GP_VECTOR, error_code); + kvm_queue_exception_e(vcpu, GP_VECTOR, 0); return 1; } -- 2.45.2