linux-kernel - [PATCH 2/2] KVM: SVM: Invoke trace_kvm

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Date:   Thu,  1 Jun 2023 18:19:20 -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
Subject: [PATCH 2/2] KVM: SVM: Invoke trace_kvm_exit() for fastpath VM-Exits

Move SVM's call to trace_kvm_exit() from the "slow" VM-Exit handler to
svm_vcpu_run() so that KVM traces fastpath VM-Exits that re-enter the
guest without bouncing through the slow path.  This bug is benign in the
current code base as KVM doesn't currently support any such exits on SVM.

Fixes: a9ab13ff6e84 ("KVM: X86: Improve latency for single target IPI fastpath")
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/svm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ca32389f3c36..6845f4f2dc33 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3418,8 +3418,6 @@ static int svm_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	struct kvm_run *kvm_run = vcpu->run;
 	u32 exit_code = svm->vmcb->control.exit_code;
 
-	trace_kvm_exit(vcpu, KVM_ISA_SVM);
-
 	/* SEV-ES guests must use the CR write traps to track CR registers. */
 	if (!sev_es_guest(vcpu->kvm)) {
 		if (!svm_is_intercept(svm, INTERCEPT_CR0_WRITE))
@@ -4156,6 +4154,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 		     SVM_EXIT_EXCP_BASE + MC_VECTOR))
 		svm_handle_mce(vcpu);
 
+	trace_kvm_exit(vcpu, KVM_ISA_SVM);
+
 	svm_complete_interrupts(vcpu);
 
 	if (is_guest_mode(vcpu))
-- 
2.41.0.rc2.161.g9c6817b8e7-goog