[3.16.y-ckt extended stable] Patch "kvm: x86: don't kill guest on unknown exit reason" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    kvm: x86: don't kill guest on unknown exit reason

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 395f428dc39832136a6bafb78a9a6b2a48ca3668 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst at redhat.com>
Date: Thu, 18 Sep 2014 16:21:16 +0300
Subject: kvm: x86: don't kill guest on unknown exit reason

commit 2bc19dc3754fc066c43799659f0d848631c44cfe upstream.

KVM_EXIT_UNKNOWN is a kvm bug, we don't really know whether it was
triggered by a priveledged application.  Let's not kill the guest: WARN
and inject #UD instead.

Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/x86/kvm/svm.c | 6 +++---
 arch/x86/kvm/vmx.c | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ee77b4bfa88b..1c10d9071958 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3528,9 +3528,9 @@ static int handle_exit(struct kvm_vcpu *vcpu)

 	if (exit_code >= ARRAY_SIZE(svm_exit_handlers)
 	    || !svm_exit_handlers[exit_code]) {
-		kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
-		kvm_run->hw.hardware_exit_reason = exit_code;
-		return 0;
+		WARN_ONCE(1, "vmx: unexpected exit reason 0x%x\n", exit_code);
+		kvm_queue_exception(vcpu, UD_VECTOR);
+		return 1;
 	}

 	return svm_exit_handlers[exit_code](svm);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5f885b760846..515704968236 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7044,10 +7044,10 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
 	    && kvm_vmx_exit_handlers[exit_reason])
 		return kvm_vmx_exit_handlers[exit_reason](vcpu);
 	else {
-		vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
-		vcpu->run->hw.hardware_exit_reason = exit_reason;
+		WARN_ONCE(1, "vmx: unexpected exit reason 0x%x\n", exit_reason);
+		kvm_queue_exception(vcpu, UD_VECTOR);
+		return 1;
 	}
-	return 0;
 }

 static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
--
2.1.0