diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-06-15 16:12:59 +0300 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-09-03 21:31:26 +0200 |
| commit | 06508c9b0d906d158bf6023feee57e617cefac32 (patch) | |
| tree | fc3a13b29f837606830d6cd2290687537acfd8a6 | |
| parent | 3501de9d423faad2a8b94606a962a90050127b19 (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: Jiri Slaby <jslaby@suse.cz>
| -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 92e6f4a8ba0e..3ee4472cef19 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2012,6 +2012,7 @@ 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) @@ -2021,6 +2022,9 @@ 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; } |