[PATCH v4 03/12] KVM: x86/mmu: Use KVM honors guest MTRRs helper when CR0.CD toggles

From: Yan Zhao
Date: Fri Jul 14 2023 - 03:18:35 EST


Zap SPTEs when CR0.CD is toggled if and only if KVM's MMU is honoring
guest MTRRs, which is the only time that KVM incorporates the guest's
CR0.CD into the final memtype.

Suggested-by: Chao Gao <chao.gao@xxxxxxxxx>
Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
---
arch/x86/kvm/x86.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9e7186864542..6693daeb5686 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -942,7 +942,7 @@ void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned lon
kvm_mmu_reset_context(vcpu);

if (((cr0 ^ old_cr0) & X86_CR0_CD) &&
- kvm_arch_has_noncoherent_dma(vcpu->kvm) &&
+ kvm_mmu_honors_guest_mtrrs(vcpu->kvm) &&
!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
kvm_zap_gfn_range(vcpu->kvm, 0, ~0ULL);
}
--
2.17.1