Re: [PATCH v2 3/3] KVM: x86 emulator: fix REPZ/REPNZ termination condition

[Avi Kivity <avi@redhat.com>]

  On 08/19/2010 01:55 PM, Gleb Natapov wrote:
> On Tue, Aug 17, 2010 at 07:44:20PM +0300, Avi Kivity wrote:
>>   	if ((c->src.type == OP_MEM)&&  !(c->d&  NoAccess)) {
>> @@ -3230,13 +3212,29 @@ writeback:
>>   	if (c->rep_prefix&&  (c->d&  String)) {
>>   		struct read_cache *rc =&ctxt->decode.io_read;
>>   		register_address_increment(c,&c->regs[VCPU_REGS_RCX], -1);
>> +		/* The second termination condition only applies for REPE
>> +		 * and REPNE. Test if the repeat string operation prefix is
>> +		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
>> +		 * corresponding termination condition according to:
>> +		 * 	- if REPE/REPZ and ZF = 0 then done
>> +		 * 	- if REPNE/REPNZ and ZF = 1 then done
>> +		 */
>> +		if (((c->b == 0xa6) || (c->b == 0xa7) ||
>> +		     (c->b == 0xae) || (c->b == 0xaf))
>> +		&&  (((c->rep_prefix == REPE_PREFIX)&&
>> +			 ((ctxt->eflags&  EFLG_ZF) == 0))
>> +			|| ((c->rep_prefix == REPNE_PREFIX)&&
>> +			    ((ctxt->eflags&  EFLG_ZF) == EFLG_ZF))))
>> +			ctxt->restart = false;
>>   		/*
>>   		 * Re-enter guest when pio read ahead buffer is empty or,
>>   		 * if it is not used, after each 1024 iteration.
>>   		 */
>> -		if ((rc->end == 0&&  !(c->regs[VCPU_REGS_RCX]&  0x3ff)) ||
>> -		    (rc->end != 0&&  rc->end == rc->pos))
>> +		else if ((rc->end == 0&&  !(c->regs[VCPU_REGS_RCX]&  0x3ff)) ||
>> +			 (rc->end != 0&&  rc->end == rc->pos)) {
>>   			ctxt->restart = false;
>> +			c->eip = ctxt->eip;
> If io exit to use space is needed we may not get here, so ctxt->eip will
> be updated to point past instruction in the middle of instruction
> emulation and that may cause incomplete instruction emulation.

Right.  Fixing this made -cdrom work again.

Will post an updated patch.

-- 
error compiling committee.c: too many arguments to function