diff options
| author | Brijesh Singh | 2017-08-17 18:36:57 +0200 |
|---|---|---|
| committer | Radim Krčmář | 2017-08-18 14:37:49 +0200 |
| commit | 618232e2196a6db1ed66b5e1ec049e5c46480f49 (patch) | |
| tree | 709c8d0d99cb3bdcd29fcc70f5f01122c58ab686 /arch/x86/kvm/x86.c | |
| parent | KVM: x86: simplify ept_misconfig (diff) | |
| download | kernel-qcow2-linux-618232e2196a6db1ed66b5e1ec049e5c46480f49.tar.gz kernel-qcow2-linux-618232e2196a6db1ed66b5e1ec049e5c46480f49.tar.xz kernel-qcow2-linux-618232e2196a6db1ed66b5e1ec049e5c46480f49.zip | |
KVM: x86: Avoid guest page table walk when gpa_available is set
When a guest causes a page fault 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.singh@amd.com>
[Fix EPT=0 according to Wanpeng Li's fix, plus ensure VMX also uses the
new code. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[Moved "ret < 0" to the else brach, as per David's review. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 24 |
1 files changed, 9 insertions, 15 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e10eda86bc7b..4e699238a113 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4657,25 +4657,18 @@ 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; + (addr & ~PAGE_MASK) == (vcpu->arch.gpa_val & ~PAGE_MASK)) { + 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); + if (ret < 0) + return X86EMUL_PROPAGATE_FAULT; } - ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write); - - if (ret < 0) - return X86EMUL_PROPAGATE_FAULT; - - /* For APIC access vmexit */ - if (ret) - goto mmio; - - if (ops->read_write_emulate(vcpu, gpa, val, bytes)) + if (!ret && ops->read_write_emulate(vcpu, gpa, val, bytes)) return X86EMUL_CONTINUE; -mmio: /* * Is this MMIO handled locally? */ @@ -7002,6 +6995,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (vcpu->arch.apic_attention) kvm_lapic_sync_from_vapic(vcpu); + vcpu->arch.gpa_available = false; r = kvm_x86_ops->handle_exit(vcpu); return r; |