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authorSean Christopherson <sean.j.christopherson@intel.com>2020-02-28 14:52:39 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2020-03-16 17:57:36 +0100
commit3651c7fc2bf63b62c009b8470aaf096b3b4b01e8 (patch)
tree68aed050454d62d7f667fe087090182f77e0381d /arch/x86/kvm/mmu
parentcc7f5577adfc766de8613b71e9ae52c053fcca01 (diff)
KVM: x86/mmu: Ignore guest CR3 on fast root switch for direct MMU
Ignore the guest's CR3 when looking for a cached root for a direct MMU, the guest's CR3 has no impact on the direct MMU's shadow pages (the role check ensures compatibility with CR0.WP, etc...). Zero out root_cr3 when allocating the direct roots to make it clear that it's ignored. Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu')
-rw-r--r--arch/x86/kvm/mmu/mmu.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c4e0b97f82ac..9d617b9dc78f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3730,7 +3730,9 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root);
} else
BUG();
- vcpu->arch.mmu->root_cr3 = vcpu->arch.mmu->get_cr3(vcpu);
+
+ /* root_cr3 is ignored for direct MMUs. */
+ vcpu->arch.mmu->root_cr3 = 0;
return 0;
}
@@ -4272,8 +4274,8 @@ static bool cached_root_available(struct kvm_vcpu *vcpu, gpa_t new_cr3,
for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
swap(root, mmu->prev_roots[i]);
- if (new_cr3 == root.cr3 && VALID_PAGE(root.hpa) &&
- page_header(root.hpa) != NULL &&
+ if ((new_role.direct || new_cr3 == root.cr3) &&
+ VALID_PAGE(root.hpa) && page_header(root.hpa) &&
new_role.word == page_header(root.hpa)->role.word)
break;
}