linux-kernel - [PATCH] kvm: x86: move tracepoints outside extended quiescent state

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Date:	Thu, 10 Dec 2015 18:38:57 +0100
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:	bp@...en8.de, stable@...r.kernel.org
Subject: [PATCH] kvm: x86: move tracepoints outside extended quiescent state

Invoking tracepoints within kvm_guest_enter/kvm_guest_exit causes a
lockdep splat.

Cc: stable@...r.kernel.org
Reported-by: Borislav Petkov <bp@...en8.de>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm.c | 4 ++--
 arch/x86/kvm/vmx.c | 3 ++-
 arch/x86/kvm/x86.c | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 83a1c643f9a5..899c40f826dd 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3422,6 +3422,8 @@ static int handle_exit(struct kvm_vcpu *vcpu)
 	struct kvm_run *kvm_run = vcpu->run;
 	u32 exit_code = svm->vmcb->control.exit_code;
 
+	trace_kvm_exit(exit_code, vcpu, KVM_ISA_SVM);
+
 	if (!is_cr_intercept(svm, INTERCEPT_CR0_WRITE))
 		vcpu->arch.cr0 = svm->vmcb->save.cr0;
 	if (npt_enabled)
@@ -3892,8 +3894,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
 	vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
 
-	trace_kvm_exit(svm->vmcb->control.exit_code, vcpu, KVM_ISA_SVM);
-
 	if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
 		kvm_before_handle_nmi(&svm->vcpu);
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index af823a388c19..6b5605607849 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8042,6 +8042,8 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
 	u32 exit_reason = vmx->exit_reason;
 	u32 vectoring_info = vmx->idt_vectoring_info;
 
+	trace_kvm_exit(exit_reason, vcpu, KVM_ISA_VMX);
+
 	/*
 	 * Flush logged GPAs PML buffer, this will make dirty_bitmap more
 	 * updated. Another good is, in kvm_vm_ioctl_get_dirty_log, before
@@ -8668,7 +8670,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	vmx->loaded_vmcs->launched = 1;
 
 	vmx->exit_reason = vmcs_read32(VM_EXIT_REASON);
-	trace_kvm_exit(vmx->exit_reason, vcpu, KVM_ISA_VMX);
 
 	/*
 	 * the KVM_REQ_EVENT optimization bit is only on for one entry, and if
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index eed32283d22c..2a8c035ec7fe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6515,6 +6515,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (req_immediate_exit)
 		smp_send_reschedule(vcpu->cpu);
 
+	trace_kvm_entry(vcpu->vcpu_id);
 	__kvm_guest_enter();
 
 	if (unlikely(vcpu->arch.switch_db_regs)) {
@@ -6527,7 +6528,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;
 	}
 
-	trace_kvm_entry(vcpu->vcpu_id);
 	wait_lapic_expire(vcpu);
 	kvm_x86_ops->run(vcpu);
 
-- 
1.8.3.1

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