From 07702e5a6d6d62266e5f156f23b00a272af64c8e Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc@google.com>
Date: Tue, 27 Feb 2024 18:41:39 -0800
Subject: [PATCH] KVM: x86/mmu: WARN and skip MMIO cache on private, reserved
page faults
WARN and skip the emulated MMIO fastpath if a private, reserved page fault
is encountered, as private+reserved should be an impossible combination
(KVM should never create an MMIO SPTE for a private access).
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240228024147.41573-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/mmu/mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4bb121b5f58e4..9560fca3a6cf6 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5818,6 +5818,9 @@ int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 err
r = RET_PF_INVALID;
if (unlikely(error_code & PFERR_RSVD_MASK)) {
+ if (WARN_ON_ONCE(error_code & PFERR_PRIVATE_ACCESS))
+ return -EFAULT;
+
r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct);
if (r == RET_PF_EMULATE)
goto emulate;
--
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