linux-kernel - [RESEND PATCH 11/13] KVM: x86: Move triple fault request into RM int injection

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Date:   Thu, 22 Aug 2019 18:07:07 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [RESEND PATCH 11/13] KVM: x86: Move triple fault request into RM int injection

Request triple fault in kvm_inject_realmode_interrupt() instead of
returning EMULATE_FAIL and deferring to the caller.  All existing
callers request triple fault and it's highly unlikely Real Mode is
going to acquire new features.  While this consolidates a small amount
of code, the real goal is to remove the last reference to EMULATE_FAIL.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/vmx/vmx.c |  9 +++------
 arch/x86/kvm/x86.c     | 17 ++++++++---------
 arch/x86/kvm/x86.h     |  2 +-
 3 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 52d5705ff7dc..efc2f913ca19 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1527,8 +1527,7 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu)
 		int inc_eip = 0;
 		if (kvm_exception_is_soft(nr))
 			inc_eip = vcpu->arch.event_exit_inst_len;
-		if (kvm_inject_realmode_interrupt(vcpu, nr, inc_eip) != EMULATE_DONE)
-			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
+		kvm_inject_realmode_interrupt(vcpu, nr, inc_eip);
 		return;
 	}
 
@@ -4276,8 +4275,7 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu)
 		int inc_eip = 0;
 		if (vcpu->arch.interrupt.soft)
 			inc_eip = vcpu->arch.event_exit_inst_len;
-		if (kvm_inject_realmode_interrupt(vcpu, irq, inc_eip) != EMULATE_DONE)
-			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
+		kvm_inject_realmode_interrupt(vcpu, irq, inc_eip);
 		return;
 	}
 	intr = irq | INTR_INFO_VALID_MASK;
@@ -4313,8 +4311,7 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
 	vmx->loaded_vmcs->nmi_known_unmasked = false;
 
 	if (vmx->rmode.vm86_active) {
-		if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0) != EMULATE_DONE)
-			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
+		kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0);
 		return;
 	}
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 83b3c7e9fce7..e457363622e5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6176,7 +6176,7 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
 	vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
 }
 
-int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
+void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
 {
 	struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
 	int ret;
@@ -6188,14 +6188,13 @@ int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
 	ctxt->_eip = ctxt->eip + inc_eip;
 	ret = emulate_int_real(ctxt, irq);
 
-	if (ret != X86EMUL_CONTINUE)
-		return EMULATE_FAIL;
-
-	ctxt->eip = ctxt->_eip;
-	kvm_rip_write(vcpu, ctxt->eip);
-	kvm_set_rflags(vcpu, ctxt->eflags);
-
-	return EMULATE_DONE;
+	if (ret != X86EMUL_CONTINUE) {
+		kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
+	} else {
+		ctxt->eip = ctxt->_eip;
+		kvm_rip_write(vcpu, ctxt->eip);
+		kvm_set_rflags(vcpu, ctxt->eflags);
+	}
 }
 EXPORT_SYMBOL_GPL(kvm_inject_realmode_interrupt);
 
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index b5274e2a53cf..dbf7442a822b 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -261,7 +261,7 @@ static inline bool kvm_check_has_quirk(struct kvm *kvm, u64 quirk)
 }
 
 void kvm_set_pending_timer(struct kvm_vcpu *vcpu);
-int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
+void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
 
 void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr);
 u64 get_kvmclock_ns(struct kvm *kvm);
-- 
2.22.0