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KVM: x86: Emulator support for #UD on CPL>0

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Certain instructions (e.g., mwait and monitor) cause a #UD exception when they
are executed in user mode. This is in contrast to the regular privileged
instructions which cause #GP. In order not to mess with SVM interception of
mwait and monitor which assumes privilege level assertions take place before
interception, a flag has been added.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Nadav Amit 2014-06-18 17:19:35 +03:00 committed by Paolo Bonzini
parent 10e38fc7ca
commit 68efa764f3
1 changed files with 5 additions and 1 deletions
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6
arch/x86/kvm/emulate.c
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@ -165,6 +165,7 @@
#define Intercept ((u64)1 << 48) /* Has valid intercept field */
#define CheckPerm ((u64)1 << 49) /* Has valid check_perm field */
#define NoBigReal ((u64)1 << 50) /* No big real mode */
#define PrivUD ((u64)1 << 51) /* #UD instead of #GP on CPL > 0 */
#define DstXacc (DstAccLo | SrcAccHi | SrcWrite)
@ -4608,7 +4609,10 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
/* Privileged instruction can be executed only in CPL=0 */
if ((ctxt->d & Priv) && ops->cpl(ctxt)) {
rc = emulate_gp(ctxt, 0);
if (ctxt->d & PrivUD)
rc = emulate_ud(ctxt);
else
rc = emulate_gp(ctxt, 0);
goto done;
}