diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-06-15 16:12:59 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-09-13 23:41:37 +0100 |
| commit | 1217c0c7df80f3663a67473e8d25ab06dbd41fb9 (patch) | |
| tree | 515ab8283360caaeb2edf5ba41a421d62e64f8ae /arch/x86 | |
| parent | 73886aa084e0c32293a609532b629f813eb42fdd (diff) | |
KVM: x86: Inter-privilege level ret emulation is not implemeneted
commit 9e8919ae793f4edfaa29694a70f71a515ae9942a upstream.
Return unhandlable error on inter-privilege level ret instruction. This is
since the current emulation does not check the privilege level correctly when
loading the CS, and does not pop RSP/SS as needed.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index f5302da9af21..638cab52ff28 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1818,6 +1818,7 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt) { int rc; unsigned long cs; + int cpl = ctxt->ops->cpl(ctxt); rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes); if (rc != X86EMUL_CONTINUE) @@ -1827,6 +1828,9 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt) rc = emulate_pop(ctxt, &cs, ctxt->op_bytes); if (rc != X86EMUL_CONTINUE) return rc; + /* Outer-privilege level return is not implemented */ + if (ctxt->mode >= X86EMUL_MODE_PROT16 && (cs & 3) > cpl) + return X86EMUL_UNHANDLEABLE; rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS); return rc; } |