diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-12-10 11:19:04 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-12-10 12:53:37 +0100 |
| commit | 64a38292ed5f1e9d1bbc15b591cc3b57ce89473f (patch) | |
| tree | d3be824a5fc8c034cea5aa3e157ebec6efeda7e7 /arch/x86 | |
| parent | bc397a6c914c75d8ae21dad23eba9ae82e34dad3 (diff) | |
KVM: x86: Emulate should check #UD before #GP
Intel SDM table 6-2 ("Priority Among Simultaneous Exceptions and Interrupts")
shows that faults from decoding the next instruction got higher priority than
general protection. Moving the protected-mode check before the CPL check to
avoid wrong exception on vm86 mode.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index c1e71873e0c7..a8fcec6b7063 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4801,6 +4801,12 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) goto done; } + /* Instruction can only be executed in protected mode */ + if ((ctxt->d & Prot) && ctxt->mode < X86EMUL_MODE_PROT16) { + rc = emulate_ud(ctxt); + goto done; + } + /* Privileged instruction can be executed only in CPL=0 */ if ((ctxt->d & Priv) && ops->cpl(ctxt)) { if (ctxt->d & PrivUD) @@ -4810,12 +4816,6 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) goto done; } - /* Instruction can only be executed in protected mode */ - if ((ctxt->d & Prot) && ctxt->mode < X86EMUL_MODE_PROT16) { - rc = emulate_ud(ctxt); - goto done; - } - /* Do instruction specific permission checks */ if (ctxt->d & CheckPerm) { rc = ctxt->check_perm(ctxt); |