From: Nadav Amit <namit@cs.technion.ac.il>
Date: Fri, 29 Aug 2014 08:26:55 +0000 (+0300)
Subject: KVM: vmx: VMXOFF emulation in vm86 should cause #UD
X-Git-Tag: fixes-for-v3.18-merge-window~23^2~59
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f54a321302dfbdbd707ba989b2f468e58b9a363;p=pandora-kernel.git

KVM: vmx: VMXOFF emulation in vm86 should cause #UD

Unlike VMCALL, the instructions VMXOFF, VMLAUNCH and VMRESUME should cause a UD
exception in real-mode or vm86.  However, the emulator considers all these
instructions the same for the matter of mode checks, and emulation upon exit
due to #UD exception.

As a result, the hypervisor behaves incorrectly on vm86 mode. VMXOFF, VMLAUNCH
or VMRESUME cause on vm86 exit due to #UD. The hypervisor then emulates these
instruction and inject #GP to the guest instead of #UD.

This patch creates a new group for these instructions and mark only VMCALL as
an instruction which can be emulated.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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