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Replace pending exception by PF if it happens serially.

PATCH Applied Gleb Natapov 2 participants 2 messages Jun 11, 2009 – Jun 14, 2009

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x86 KVM KVM x86
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Gleb Natapov

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#0 lore raw

PATCH 1/1 Replace pending exception by PF if it happens serially.

Replace previous exception with a new one in a hope that instruction re-execution will regenerate lost exception.

Signed-off-by Gleb Natapov <[email protected]>
arch/x86/kvm/x86.c +12 -7
index 272e2e8..3150d06 100644
@@ -181,16 +181,21 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
 	++vcpu->stat.pf_guest;
 
 	if (vcpu->arch.exception.pending) {
-		if (vcpu->arch.exception.nr == PF_VECTOR) {
-			printk(KERN_DEBUG "kvm: inject_page_fault:"
-					" double fault 0x%lx\n", addr);
-			vcpu->arch.exception.nr = DF_VECTOR;
-			vcpu->arch.exception.error_code = 0;
-		} else if (vcpu->arch.exception.nr == DF_VECTOR) {
+		switch(vcpu->arch.exception.nr) {
+		case DF_VECTOR:
 			/* triple fault -> shutdown */
 			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
+		case PF_VECTOR:
+			vcpu->arch.exception.nr = DF_VECTOR;
+			vcpu->arch.exception.error_code = 0;
+			return;
+		default:
+			/* replace previous exception with a new one in a hope
+			   that instruction re-execution will regenerate lost
+			   exception */
+			vcpu->arch.exception.pending = false;
+			break;
 		}
-		return;
 	}
 	vcpu->arch.cr2 = addr;
 	kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);

--
Gleb.

Applied
#1 lore raw
Quoted 4 lines · Gleb Natapov

Replace previous exception with a new one in a hope that instruction re-execution will regenerate lost exception.

Applied, thanks.

arch/x86/kvm/x86.c void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr, · line 187

Quoted 5 lines
arch/x86/kvm/x86.c +2 -0
+		switch(vcpu->arch.exception.nr) {
+		case DF_VECTOR:
 			/* triple fault -> shutdown */
 			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);

Added a 'return' here. It will work without, but will raise endless questions from people who look at the code.

Quoted 13 lines
arch/x86/kvm/x86.c +10 -1
+		case PF_VECTOR:
+			vcpu->arch.exception.nr = DF_VECTOR;
+			vcpu->arch.exception.error_code = 0;
+			return;
+		default:
+			/* replace previous exception with a new one in a hope
+			   that instruction re-execution will regenerate lost
+			   exception */
+			vcpu->arch.exception.pending = false;
+			break;
 		}
-		return;
 	}
Signature · 1 line
error compiling committee.c: too many arguments to function