linux-kernel - [PATCH v2 12/18] KVM: x86/mmu: clear MMIO cache when unloading the MMU

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Message-Id: <20220217210340.312449-13-pbonzini@redhat.com>
Date:   Thu, 17 Feb 2022 16:03:34 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH v2 12/18] KVM: x86/mmu: clear MMIO cache when unloading the MMU

For cleanliness, do not leave a stale GVA in the cache after all the roots are
cleared.  In practice, kvm_mmu_load will go through kvm_mmu_sync_roots if
paging is on, and will not use vcpu_match_mmio_gva at all if paging is off.
However, leaving data in the cache might cause bugs in the future.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/mmu/mmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b01160716c6a..4e8e3e9530ca 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5111,6 +5111,7 @@ void kvm_mmu_unload(struct kvm_vcpu *vcpu)
 {
 	__kvm_mmu_unload(vcpu->kvm, &vcpu->arch.root_mmu);
 	__kvm_mmu_unload(vcpu->kvm, &vcpu->arch.guest_mmu);
+	vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
 }
 
 static bool need_remote_flush(u64 old, u64 new)
-- 
2.31.1