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

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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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Nadav Amit 2014-08-29 11:26:55 +03:00 • committed by Paolo Bonzini

parent 48d89b9260

commit 0f54a32130

1 changed files with 8 additions and 6 deletions

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arch/x86/kvm/emulate.c

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