Commit a825f5cc authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini

KVM: x86: NOP emulation clears (incorrectly) the high 32-bits of RAX

On long-mode the current NOP (0x90) emulation still writes back to RAX.  As a
result, EAX is zero-extended and the high 32-bits of RAX are cleared.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 140bad89
...@@ -4688,8 +4688,9 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) ...@@ -4688,8 +4688,9 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
break; break;
case 0x90 ... 0x97: /* nop / xchg reg, rax */ case 0x90 ... 0x97: /* nop / xchg reg, rax */
if (ctxt->dst.addr.reg == reg_rmw(ctxt, VCPU_REGS_RAX)) if (ctxt->dst.addr.reg == reg_rmw(ctxt, VCPU_REGS_RAX))
break; ctxt->dst.type = OP_NONE;
rc = em_xchg(ctxt); else
rc = em_xchg(ctxt);
break; break;
case 0x98: /* cbw/cwde/cdqe */ case 0x98: /* cbw/cwde/cdqe */
switch (ctxt->op_bytes) { switch (ctxt->op_bytes) {
......
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