Patch "KVM: x86: Don't report guest userspace emulation error to userspace" has been added to the 3.10-stable tree

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This is a note to let you know that I've just added the patch titled

    KVM: x86: Don't report guest userspace emulation error to userspace

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-x86-don-t-report-guest-userspace-emulation-error-to-userspace.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From a2b9e6c1a35afcc0973acb72e591c714e78885ff Mon Sep 17 00:00:00 2001
From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Date: Wed, 17 Sep 2014 02:50:50 +0300
Subject: KVM: x86: Don't report guest userspace emulation error to userspace

From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>

commit a2b9e6c1a35afcc0973acb72e591c714e78885ff upstream.

Commit fc3a9157d314 ("KVM: X86: Don't report L2 emulation failures to
user-space") disabled the reporting of L2 (nested guest) emulation failures to
userspace due to race-condition between a vmexit and the instruction emulator.
The same rational applies also to userspace applications that are permitted by
the guest OS to access MMIO area or perform PIO.

This patch extends the current behavior - of injecting a #UD instead of
reporting it to userspace - also for guest userspace code.

Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/kvm/x86.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4834,7 +4834,7 @@ static int handle_emulation_failure(stru
 
 	++vcpu->stat.insn_emulation_fail;
 	trace_kvm_emulate_insn_failed(vcpu);
-	if (!is_guest_mode(vcpu)) {
+	if (!is_guest_mode(vcpu) && kvm_x86_ops->get_cpl(vcpu) == 0) {
 		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
 		vcpu->run->internal.ndata = 0;


Patches currently in stable-queue which might be from namit@xxxxxxxxxxxxxxxxx are

queue-3.10/kvm-x86-don-t-report-guest-userspace-emulation-error-to-userspace.patch
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