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| author | Brijesh Singh <brijesh.singh@amd.com> | 2017-08-17 18:36:57 +0200 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2017-08-18 14:37:49 +0200 |
| commit | 618232e2196a6db1ed66b5e1ec049e5c46480f49 (patch) | |
| tree | 709c8d0d99cb3bdcd29fcc70f5f01122c58ab686 /arch/x86/kvm/mmu.c | |
| parent | e08d26f0712532c79b5ba6200862eaf2036f8df6 (diff) | |
| download | linux-618232e2196a6db1ed66b5e1ec049e5c46480f49.tar.bz2 | |
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/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index f7598883920a..a2c592b14617 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4843,6 +4843,12 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code, enum emulation_result er; bool direct = vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu); + /* With shadow page tables, fault_address contains a GVA or nGPA. */ + if (vcpu->arch.mmu.direct_map) { + vcpu->arch.gpa_available = true; + vcpu->arch.gpa_val = cr2; + } + if (unlikely(error_code & PFERR_RSVD_MASK)) { r = handle_mmio_page_fault(vcpu, cr2, direct); if (r == RET_MMIO_PF_EMULATE) { |