* [Qemu-devel] bug in popcnt emulation with some register operand(s)?
@ 2012-10-07 23:12 Andriy Gapon
2012-10-08 7:52 ` malc
0 siblings, 1 reply; 8+ messages in thread
From: Andriy Gapon @ 2012-10-07 23:12 UTC (permalink / raw)
To: qemu-devel
I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that provides
popcnt instruction.
Qemu advertises availability of pocnt to a guest as well.
What I see in the guest that popcnt 0x20(%r12),%r8 instruction actually placed
its result into %rax. With %rdi and %rax operands the instruction worked fine
though.
--
Andriy Gapon
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-07 23:12 [Qemu-devel] bug in popcnt emulation with some register operand(s)? Andriy Gapon
@ 2012-10-08 7:52 ` malc
2012-10-08 9:02 ` Andriy Gapon
0 siblings, 1 reply; 8+ messages in thread
From: malc @ 2012-10-08 7:52 UTC (permalink / raw)
To: Andriy Gapon; +Cc: qemu-devel
On Mon, 8 Oct 2012, Andriy Gapon wrote:
>
> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
> provides popcnt instruction. Qemu advertises availability of pocnt
> to a guest as well. What I see in the guest that popcnt
> 0x20(%r12),%r8 instruction actually placed its result into %rax.
> With %rdi and %rax operands the instruction worked fine though.
>
>
Does following work?
diff --git a/target-i386/translate.c b/target-i386/translate.c
index e896abf..c36cc3e 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -7818,7 +7818,7 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
goto illegal_op;
modrm = cpu_ldub_code(cpu_single_env, s->pc++);
- reg = ((modrm >> 3) & 7);
+ reg = ((modrm >> 3) & 7) | rex_r;
if (s->prefix & PREFIX_DATA)
ot = OT_WORD;
--
mailto:av1474@comtv.ru
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-08 7:52 ` malc
@ 2012-10-08 9:02 ` Andriy Gapon
2012-10-10 21:03 ` Andriy Gapon
0 siblings, 1 reply; 8+ messages in thread
From: Andriy Gapon @ 2012-10-08 9:02 UTC (permalink / raw)
To: malc; +Cc: qemu-devel
on 08/10/2012 10:52 malc said the following:
> On Mon, 8 Oct 2012, Andriy Gapon wrote:
>
>>
>> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
>> provides popcnt instruction. Qemu advertises availability of pocnt
>> to a guest as well. What I see in the guest that popcnt
>> 0x20(%r12),%r8 instruction actually placed its result into %rax.
>> With %rdi and %rax operands the instruction worked fine though.
>>
>>
>
> Does following work?
It does! Thank you very much.
> diff --git a/target-i386/translate.c b/target-i386/translate.c
> index e896abf..c36cc3e 100644
> --- a/target-i386/translate.c
> +++ b/target-i386/translate.c
> @@ -7818,7 +7818,7 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
> goto illegal_op;
>
> modrm = cpu_ldub_code(cpu_single_env, s->pc++);
> - reg = ((modrm >> 3) & 7);
> + reg = ((modrm >> 3) & 7) | rex_r;
>
> if (s->prefix & PREFIX_DATA)
> ot = OT_WORD;
>
--
Andriy Gapon
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-08 9:02 ` Andriy Gapon
@ 2012-10-10 21:03 ` Andriy Gapon
2012-10-10 21:09 ` malc
0 siblings, 1 reply; 8+ messages in thread
From: Andriy Gapon @ 2012-10-10 21:03 UTC (permalink / raw)
To: malc, qemu-devel
on 08/10/2012 12:02 Andriy Gapon said the following:
> on 08/10/2012 10:52 malc said the following:
>> On Mon, 8 Oct 2012, Andriy Gapon wrote:
>>
>>>
>>> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
>>> provides popcnt instruction. Qemu advertises availability of pocnt
>>> to a guest as well. What I see in the guest that popcnt
>>> 0x20(%r12),%r8 instruction actually placed its result into %rax.
>>> With %rdi and %rax operands the instruction worked fine though.
>>>
>>>
>>
>> Does following work?
>
> It does! Thank you very much.
Do you plan to commit this fix?
Is there anything that I should do to make that happen (sooner)?
>> diff --git a/target-i386/translate.c b/target-i386/translate.c
>> index e896abf..c36cc3e 100644
>> --- a/target-i386/translate.c
>> +++ b/target-i386/translate.c
>> @@ -7818,7 +7818,7 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
>> goto illegal_op;
>>
>> modrm = cpu_ldub_code(cpu_single_env, s->pc++);
>> - reg = ((modrm >> 3) & 7);
>> + reg = ((modrm >> 3) & 7) | rex_r;
>>
>> if (s->prefix & PREFIX_DATA)
>> ot = OT_WORD;
>>
>
>
--
Andriy Gapon
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-10 21:03 ` Andriy Gapon
@ 2012-10-10 21:09 ` malc
2012-10-14 10:25 ` Andriy Gapon
0 siblings, 1 reply; 8+ messages in thread
From: malc @ 2012-10-10 21:09 UTC (permalink / raw)
To: Andriy Gapon; +Cc: qemu-devel
On Thu, 11 Oct 2012, Andriy Gapon wrote:
> on 08/10/2012 12:02 Andriy Gapon said the following:
> > on 08/10/2012 10:52 malc said the following:
> >> On Mon, 8 Oct 2012, Andriy Gapon wrote:
> >>
> >>>
> >>> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
> >>> provides popcnt instruction. Qemu advertises availability of pocnt
> >>> to a guest as well. What I see in the guest that popcnt
> >>> 0x20(%r12),%r8 instruction actually placed its result into %rax.
> >>> With %rdi and %rax operands the instruction worked fine though.
> >>>
> >>>
> >>
> >> Does following work?
> >
> > It does! Thank you very much.
>
> Do you plan to commit this fix?
> Is there anything that I should do to make that happen (sooner)?
>
Submit a patch with a well thought out comment and it'll be commited.
[..snip..]
--
mailto:av1474@comtv.ru
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-10 21:09 ` malc
@ 2012-10-14 10:25 ` Andriy Gapon
2012-10-14 10:56 ` malc
0 siblings, 1 reply; 8+ messages in thread
From: Andriy Gapon @ 2012-10-14 10:25 UTC (permalink / raw)
To: malc; +Cc: qemu-devel
on 11/10/2012 00:09 malc said the following:
> On Thu, 11 Oct 2012, Andriy Gapon wrote:
>
>> on 08/10/2012 12:02 Andriy Gapon said the following:
>>> on 08/10/2012 10:52 malc said the following:
>>>> On Mon, 8 Oct 2012, Andriy Gapon wrote:
>>>>
>>>>>
>>>>> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
>>>>> provides popcnt instruction. Qemu advertises availability of pocnt
>>>>> to a guest as well. What I see in the guest that popcnt
>>>>> 0x20(%r12),%r8 instruction actually placed its result into %rax.
>>>>> With %rdi and %rax operands the instruction worked fine though.
>>>>>
>>>>>
>>>>
>>>> Does following work?
>>>
>>> It does! Thank you very much.
>>
>> Do you plan to commit this fix?
>> Is there anything that I should do to make that happen (sooner)?
>>
>
> Submit a patch with a well thought out comment and it'll be commited.
>
> [..snip..]
>
Hmm... Since you are the author of the patch, wouldn't be more appropriate for
you to submit it? Besides, I can only mostly repeat the bug report as I do not
quite understand the code and can not properly describe what the patch does.
Sorry for not taking up the work, but I am really just a qemu user.
--
Andriy Gapon
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-14 10:25 ` Andriy Gapon
@ 2012-10-14 10:56 ` malc
2012-10-14 11:01 ` Andriy Gapon
0 siblings, 1 reply; 8+ messages in thread
From: malc @ 2012-10-14 10:56 UTC (permalink / raw)
To: Andriy Gapon; +Cc: qemu-devel
On Sun, 14 Oct 2012, Andriy Gapon wrote:
[..snip..]
>
> Hmm... Since you are the author of the patch, wouldn't be more
> appropriate for you to submit it? Besides, I can only mostly repeat the
> bug report as I do not quite understand the code and can not properly
> describe what the patch does.
Sigh, okay, commited.
>
> Sorry for not taking up the work, but I am really just a qemu user.
>
>
--
mailto:av1474@comtv.ru
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
2012-10-14 10:56 ` malc
@ 2012-10-14 11:01 ` Andriy Gapon
0 siblings, 0 replies; 8+ messages in thread
From: Andriy Gapon @ 2012-10-14 11:01 UTC (permalink / raw)
To: malc; +Cc: qemu-devel
on 14/10/2012 13:56 malc said the following:
> On Sun, 14 Oct 2012, Andriy Gapon wrote:
>
> [..snip..]
>
>>
>> Hmm... Since you are the author of the patch, wouldn't be more
>> appropriate for you to submit it? Besides, I can only mostly repeat the
>> bug report as I do not quite understand the code and can not properly
>> describe what the patch does.
>
> Sigh, okay, commited.
Thank you again!
>>
>> Sorry for not taking up the work, but I am really just a qemu user.
>>
>>
>
--
Andriy Gapon
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2012-10-14 11:02 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
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2012-10-07 23:12 [Qemu-devel] bug in popcnt emulation with some register operand(s)? Andriy Gapon
2012-10-08 7:52 ` malc
2012-10-08 9:02 ` Andriy Gapon
2012-10-10 21:03 ` Andriy Gapon
2012-10-10 21:09 ` malc
2012-10-14 10:25 ` Andriy Gapon
2012-10-14 10:56 ` malc
2012-10-14 11:01 ` Andriy Gapon
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