linux-kernel - [PATCH v2 10/22] KVM: nVMX: Report NMIs as allowed when in L2 and Exit-on-NMI is set

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Date:   Sat, 25 Apr 2020 03:01:42 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     wei.huang2@....com, cavery@...hat.com, vkuznets@...hat.com,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Oliver Upton <oupton@...gle.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: [PATCH v2 10/22] KVM: nVMX: Report NMIs as allowed when in L2 and Exit-on-NMI is set

From: Sean Christopherson <sean.j.christopherson@...el.com>

Report NMIs as allowed when the vCPU is in L2 and L2 is being run with
Exit-on-NMI enabled, as NMIs are always unblocked from L1's perspective
in this case.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Message-Id: <20200423022550.15113-7-sean.j.christopherson@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx/nested.c | 5 -----
 arch/x86/kvm/vmx/nested.h | 5 +++++
 arch/x86/kvm/vmx/vmx.c    | 3 +++
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 182e5209a1f6..9edd9464fedf 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -698,11 +698,6 @@ static bool nested_exit_intr_ack_set(struct kvm_vcpu *vcpu)
 		VM_EXIT_ACK_INTR_ON_EXIT;
 }
 
-static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
-{
-	return nested_cpu_has_nmi_exiting(get_vmcs12(vcpu));
-}
-
 static int nested_vmx_check_apic_access_controls(struct kvm_vcpu *vcpu,
 					  struct vmcs12 *vmcs12)
 {
diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
index 7ce9572c3d3a..5cc72ae0e277 100644
--- a/arch/x86/kvm/vmx/nested.h
+++ b/arch/x86/kvm/vmx/nested.h
@@ -225,6 +225,11 @@ static inline bool nested_cpu_has_save_preemption_timer(struct vmcs12 *vmcs12)
 	    VM_EXIT_SAVE_VMX_PREEMPTION_TIMER;
 }
 
+static inline bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
+{
+	return nested_cpu_has_nmi_exiting(get_vmcs12(vcpu));
+}
+
 /*
  * In nested virtualization, check if L1 asked to exit on external interrupts.
  * For most existing hypervisors, this will always return true.
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c33317bfc1cf..37b1986a4e8f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4516,6 +4516,9 @@ static bool vmx_nmi_allowed(struct kvm_vcpu *vcpu)
 	if (to_vmx(vcpu)->nested.nested_run_pending)
 		return false;
 
+	if (is_guest_mode(vcpu) && nested_exit_on_nmi(vcpu))
+		return true;
+
 	if (!enable_vnmi &&
 	    to_vmx(vcpu)->loaded_vmcs->soft_vnmi_blocked)
 		return false;
-- 
2.18.2