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| author |   Paolo Bonzini <pbonzini@redhat.com> | 2015-07-07 14:38:13 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-07-10 13:25:27 +0200 |
| commit | fd717f11015f673487ffc826e59b2bad69d20fe5 (patch) | |
| tree | ea98f02afb5b24e2868861ae26b56308e3027051 /arch/x86/kvm/svm.c | |
| parent | KVM: SVM: Sync g_pat with guest-written PAT value (diff) | |
| download | linux-dev-fd717f11015f673487ffc826e59b2bad69d20fe5.tar.xz linux-dev-fd717f11015f673487ffc826e59b2bad69d20fe5.zip | |
KVM: x86: apply guest MTRR virtualization on host reserved pages
Currently guest MTRR is avoided if kvm_is_reserved_pfn returns true.
However, the guest could prefer a different page type than UC for
such pages. A good example is that pass-throughed VGA frame buffer is
not always UC as host expected.
This patch enables full use of virtual guest MTRRs.
Suggested-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Tested-by: Joerg Roedel <jroedel@suse.de> (on AMD)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index d36cfaf5a97a..bbc678a66b18 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1166,14 +1166,11 @@ static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) u8 mtrr; /* - * 1. MMIO: always map as UC + * 1. MMIO: trust guest MTRR, so same as item 3. * 2. No passthrough: always map as WB, and force guest PAT to WB as well * 3. Passthrough: can't guarantee the result, try to trust guest. */ - if (is_mmio) - return _PAGE_NOCACHE; - - if (!kvm_arch_has_assigned_device(vcpu->kvm)) + if (!is_mmio && !kvm_arch_has_assigned_device(vcpu->kvm)) return 0; mtrr = kvm_mtrr_get_guest_memory_type(vcpu, gfn); |