From: Brijesh Singh <brijesh.si...@amd.com> On AMD hardware when a guest causes a NPF which requires emulation, the vcpu->arch.gpa_available flag is set to indicate that cr2 contains a valid GPA.
Currently, emulator_read_write_onepage() makes use of gpa_available flag to avoid a guest page walk for a known MMIO regions. Lets not limit the gpa_available optimization to just MMIO region. The patch extends the check to avoid page walk whenever gpa_available flag is set. Signed-off-by: Brijesh Singh <brijesh.si...@amd.com> --- v1: http://marc.info/?l=kvm&m=149304930814202&w=2 Changes in v2: - move gpa_val setting in pf_interception arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm.c | 4 ++++ arch/x86/kvm/x86.c | 14 +++++++------- 3 files changed, 12 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 695605e..cc87e00 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -678,6 +678,7 @@ struct kvm_vcpu_arch { /* GPA available (AMD only) */ bool gpa_available; + gpa_t gpa_val; }; struct kvm_lpage_info { diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index c27ac69..27fb563 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2070,9 +2070,13 @@ static void svm_set_dr7(struct kvm_vcpu *vcpu, unsigned long value) static int pf_interception(struct vcpu_svm *svm) { u64 fault_address = svm->vmcb->control.exit_info_2; + struct kvm_vcpu *vcpu = &svm->vcpu; u64 error_code; int r = 1; + /* On #NPF, exit_info_2 contains a valid GPA */ + vcpu->arch.gpa_val = fault_address; + switch (svm->apf_reason) { default: error_code = svm->vmcb->control.exit_info_1; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b54125b..d2d88ed 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4634,16 +4634,16 @@ static int emulator_read_write_onepage(unsigned long addr, void *val, */ if (vcpu->arch.gpa_available && emulator_can_use_gpa(ctxt) && - vcpu_is_mmio_gpa(vcpu, addr, exception->address, write) && (addr & ~PAGE_MASK) == (exception->address & ~PAGE_MASK)) { - gpa = exception->address; - goto mmio; - } + gpa = vcpu->arch.gpa_val; + ret = vcpu_is_mmio_gpa(vcpu, addr, gpa, write); + } else { - ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write); + ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write); - if (ret < 0) - return X86EMUL_PROPAGATE_FAULT; + if (ret < 0) + return X86EMUL_PROPAGATE_FAULT; + } /* For APIC access vmexit */ if (ret) -- 2.7.4
