linux-kernel - [PATCH 2/5] KVM: SVM: Use kvm_pat_valid() directly instead of kvm_mtrr

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Message-ID: <20230503182852.3431281-3-seanjc@google.com>
Date:   Wed,  3 May 2023 11:28:49 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Wenyao Hai <haiwenyao@...ontech.com>,
        Ke Guo <guoke@...ontech.com>
Subject: [PATCH 2/5] KVM: SVM: Use kvm_pat_valid() directly instead of kvm_mtrr_valid()

From: Ke Guo <guoke@...ontech.com>

Use kvm_pat_valid() directly instead of bouncing through kvm_mtrr_valid().
The PAT is not an MTRR, and kvm_mtrr_valid() just redirects to
kvm_pat_valid(), i.e. for better or worse, KVM doesn't apply the "zap
SPTEs" logic to guest PAT changes when the VM has a passthrough device
with non-coherent DMA.

Signed-off-by: Ke Guo <guoke@...ontech.com>
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index eb308c9994f9..db237ccdc957 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2935,7 +2935,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 
 		break;
 	case MSR_IA32_CR_PAT:
-		if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
+		if (!kvm_pat_valid(data))
 			return 1;
 		vcpu->arch.pat = data;
 		svm->vmcb01.ptr->save.g_pat = data;
-- 
2.40.1.495.gc816e09b53d-goog