On 04/24/2011 10:08 AM, Matteo Signorini wrote:
Hello everybody,
I have a problem with an opcode emulation not yet emulated in kvm-kmod
2.6.38-rc7.
The opcode is the "LEAVE" that as Intel Manual says:
"Set RSP to RBP, then pop RBP"
The problem is that despite to the fact that the opcode of the leave
(C9) is correctly fetched and decoded, it falls in an infinite loop
(found by some printk debug prints)
Now I'm wondering...the eip needed in order to continue the vm
execution is moved-on by the insns_fetch operation so after the first
byte decode of the LEAVE opcode I shouldn't execute it again...so what
I'm doing wrong?
I posted here the diff output so you can see which changes I made on
kvm original source code
case 0xc5: /* lds */
rc = emulate_load_segment(ctxt, ops, VCPU_SREG_DS);
break;
+ case 0xc9: /* leave */
+ c->regs[VCPU_REGS_RSP] = c->regs[VCPU_REGS_RBP];
+ rc = emulate_pop_sreg(ctxt, ops, VCPU_REGS_RBP);
+ goto done;
case 0xcb: /* ret far */
rc = emulate_ret_far(ctxt, ops);
break;
Why are you calling emulate_pop_sreg()? RBP is not a segment register.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
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