linux-kernel - [PATCH] KVM: x86: Fix the intel_pt PMI handling wrongly considered from guest

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Date:   Mon, 16 May 2022 01:16:33 +0800
From:   Yanfei Xu <yanfei.xu@...el.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com
Cc:     x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: x86: Fix the intel_pt PMI handling wrongly considered from guest

When kernel handles the vm-exit caused by external interrupts and PMI,
it always set a type of kvm_intr_type to handling_intr_from_guest to
tell if it's dealing an IRQ or NMI.
However, the further type judgment is missing in kvm_arch_pmi_in_guest().
It could make the PMI of intel_pt wrongly considered it comes from a
guest once the PMI breaks the handling of vm-exit of external interrupts.

Fixes: db215756ae59 ("KVM: x86: More precisely identify NMI from guest when handling PMI")
Signed-off-by: Yanfei Xu <yanfei.xu@...el.com>
---
 arch/x86/include/asm/kvm_host.h | 8 +++++++-
 arch/x86/kvm/x86.h              | 6 ------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4ff36610af6a..308cf19f123d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1582,8 +1582,14 @@ static inline int kvm_arch_flush_remote_tlb(struct kvm *kvm)
 		return -ENOTSUPP;
 }
 
+enum kvm_intr_type {
+	/* Values are arbitrary, but must be non-zero. */
+	KVM_HANDLING_IRQ = 1,
+	KVM_HANDLING_NMI,
+};
+
 #define kvm_arch_pmi_in_guest(vcpu) \
-	((vcpu) && (vcpu)->arch.handling_intr_from_guest)
+	((vcpu) && (vcpu)->arch.handling_intr_from_guest == KVM_HANDLING_NMI)
 
 void kvm_mmu_x86_module_init(void);
 int kvm_mmu_vendor_module_init(void);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 588792f00334..3bdf1bc76863 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -344,12 +344,6 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm)
 	return kvm->arch.cstate_in_guest;
 }
 
-enum kvm_intr_type {
-	/* Values are arbitrary, but must be non-zero. */
-	KVM_HANDLING_IRQ = 1,
-	KVM_HANDLING_NMI,
-};
-
 static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu,
 					enum kvm_intr_type intr)
 {
-- 
2.32.0