linux-kernel - [PATCH v8 087/103] KVM: TDX: handle EXCEPTION_NMI and EXTERNAL

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Date:   Sun,  7 Aug 2022 15:02:12 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>
Subject: [PATCH v8 087/103] KVM: TDX: handle EXCEPTION_NMI and EXTERNAL_INTERRUPT

From: Isaku Yamahata <isaku.yamahata@...el.com>

Because guest TD state is protected, exceptions in guest TDs can't be
intercepted.  TDX VMM doesn't need to handle exceptions.
tdx_handle_exit_irqoff() handles NMI and machine check.  Ignore NMI and
machine check and continue guest TD execution.

For external interrupt, increment stats same to the VMX case.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx/tdx.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index de618935fe01..7524bd8374be 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -839,6 +839,25 @@ void tdx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 						     tdexit_intr_info(vcpu));
 }
 
+static int tdx_handle_exception(struct kvm_vcpu *vcpu)
+{
+	u32 intr_info = tdexit_intr_info(vcpu);
+
+	if (is_nmi(intr_info) || is_machine_check(intr_info))
+		return 1;
+
+	kvm_pr_unimpl("unexpected exception 0x%x(exit_reason 0x%llx qual 0x%lx)\n",
+		intr_info,
+		to_tdx(vcpu)->exit_reason.full, tdexit_exit_qual(vcpu));
+	return -EFAULT;
+}
+
+static int tdx_handle_external_interrupt(struct kvm_vcpu *vcpu)
+{
+	++vcpu->stat.irq_exits;
+	return 1;
+}
+
 static int tdx_handle_triple_fault(struct kvm_vcpu *vcpu)
 {
 	vcpu->run->exit_reason = KVM_EXIT_SHUTDOWN;
@@ -1248,6 +1267,10 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
 	WARN_ON_ONCE(fastpath != EXIT_FASTPATH_NONE);
 
 	switch (exit_reason.basic) {
+	case EXIT_REASON_EXCEPTION_NMI:
+		return tdx_handle_exception(vcpu);
+	case EXIT_REASON_EXTERNAL_INTERRUPT:
+		return tdx_handle_external_interrupt(vcpu);
 	case EXIT_REASON_EPT_VIOLATION:
 		return tdx_handle_ept_violation(vcpu);
 	case EXIT_REASON_EPT_MISCONFIG:
-- 
2.25.1