Commit 9e8919ae authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini

KVM: x86: Inter-privilege level ret emulation is not implemeneted

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.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ee212297
...@@ -2033,6 +2033,7 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt) ...@@ -2033,6 +2033,7 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
{ {
int rc; int rc;
unsigned long cs; unsigned long cs;
int cpl = ctxt->ops->cpl(ctxt);
rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes); rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes);
if (rc != X86EMUL_CONTINUE) if (rc != X86EMUL_CONTINUE)
...@@ -2042,6 +2043,9 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt) ...@@ -2042,6 +2043,9 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
rc = emulate_pop(ctxt, &cs, ctxt->op_bytes); rc = emulate_pop(ctxt, &cs, ctxt->op_bytes);
if (rc != X86EMUL_CONTINUE) if (rc != X86EMUL_CONTINUE)
return rc; 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); rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS);
return rc; return rc;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment