i386 emulate fixes

[PATCH 0/3] i386 emulate fixes

Posted by Bernhard Beschow 1 month, 3 weeks ago

When testing Mohamed's recent x86_64 WHPX updates [1] I encountered two
compilation issues under MSYS2/GCC which are fixed in this series. The last
commit fixes a missed optimization opportunity in MSHV code.

The MSHV code will be reused in WHPX [1] which allowed me to test it. I
didn't notice any performance benefits, though in theory there should be some
due to less guest memory accesses.

Testing done:
* Use a Linux VM for a couple of hours

[1] https://lore.kernel.org/qemu-devel/20260213034556.13471-1-mohamed@unpredictable.fr/

Bernhard Beschow (3):
  target/i386/emulate/x86_decode: Fix compiler warning
  target/i386/hvf/x86_mmu: Fix compiler warning
  target/i386/emulate/x86_decode: Actually use stream in
    decode_instruction_stream()

 target/i386/emulate/x86_decode.c | 6 +++---
 target/i386/hvf/x86_mmu.c        | 6 ++++--
 2 files changed, 7 insertions(+), 5 deletions(-)

-- 
2.53.0

Re: [PATCH 0/3] i386 emulate fixes

Posted by Wei Liu 1 month, 3 weeks ago

On Sat, Feb 14, 2026 at 02:16:56PM +0100, Bernhard Beschow wrote:
> When testing Mohamed's recent x86_64 WHPX updates [1] I encountered two
> compilation issues under MSYS2/GCC which are fixed in this series. The last
> commit fixes a missed optimization opportunity in MSHV code.
> 
> The MSHV code will be reused in WHPX [1] which allowed me to test it. I
> didn't notice any performance benefits, though in theory there should be some
> due to less guest memory accesses.
> 
> Testing done:
> * Use a Linux VM for a couple of hours
> 
> [1] https://lore.kernel.org/qemu-devel/20260213034556.13471-1-mohamed@unpredictable.fr/
> 
> Bernhard Beschow (3):
>   target/i386/emulate/x86_decode: Fix compiler warning
>   target/i386/hvf/x86_mmu: Fix compiler warning
>   target/i386/emulate/x86_decode: Actually use stream in
>     decode_instruction_stream()

Reviewed-by: Wei Liu (Microsoft) <wei.liu@kernel.org>

Re: [PATCH 0/3] i386 emulate fixes

Posted by Bernhard Beschow 1 month, 3 weeks ago


Am 18. Februar 2026 06:31:56 UTC schrieb Wei Liu <wei.liu@kernel.org>:
>On Sat, Feb 14, 2026 at 02:16:56PM +0100, Bernhard Beschow wrote:
>> When testing Mohamed's recent x86_64 WHPX updates [1] I encountered two
>> compilation issues under MSYS2/GCC which are fixed in this series. The last
>> commit fixes a missed optimization opportunity in MSHV code.
>> 
>> The MSHV code will be reused in WHPX [1] which allowed me to test it. I
>> didn't notice any performance benefits, though in theory there should be some
>> due to less guest memory accesses.
>> 
>> Testing done:
>> * Use a Linux VM for a couple of hours
>> 
>> [1] https://lore.kernel.org/qemu-devel/20260213034556.13471-1-mohamed@unpredictable.fr/
>> 
>> Bernhard Beschow (3):
>>   target/i386/emulate/x86_decode: Fix compiler warning
>>   target/i386/hvf/x86_mmu: Fix compiler warning
>>   target/i386/emulate/x86_decode: Actually use stream in
>>     decode_instruction_stream()
>
>Reviewed-by: Wei Liu (Microsoft) <wei.liu@kernel.org>

Hi Wei,

thanks for the tag! Note that there is a new series including this one: https://lore.kernel.org/qemu-devel/20260215052225.22513-1-mohamed@unpredictable.fr/ So for the tag to be considered it should be added to the individual patches there.

Thanks,
Bernhard

Re: [PATCH 0/3] i386 emulate fixes

Posted by Mohamed Mediouni 1 month, 3 weeks ago


> On 14. Feb 2026, at 14:16, Bernhard Beschow <shentey@gmail.com> wrote:
> 
> When testing Mohamed's recent x86_64 WHPX updates [1] I encountered two
> compilation issues under MSYS2/GCC which are fixed in this series. The last
> commit fixes a missed optimization opportunity in MSHV code.
> 
> The MSHV code will be reused in WHPX [1] which allowed me to test it. I
> didn't notice any performance benefits, though in theory there should be some
> due to less guest memory accesses.
> 
> Testing done:
> * Use a Linux VM for a couple of hours
> 
> [1] https://lore.kernel.org/qemu-devel/20260213034556.13471-1-mohamed@unpredictable.fr/
> 
> Bernhard Beschow (3):
>  target/i386/emulate/x86_decode: Fix compiler warning
>  target/i386/hvf/x86_mmu: Fix compiler warning
>  target/i386/emulate/x86_decode: Actually use stream in
>    decode_instruction_stream()
> 
For the series:

Reviewed-by: Mohamed Mediouni <mohamed@unpredictable.fr <mailto:mohamed@unpredictable.fr>>

> target/i386/emulate/x86_decode.c | 6 +++---
> target/i386/hvf/x86_mmu.c        | 6 ++++--
> 2 files changed, 7 insertions(+), 5 deletions(-)
> 
> -- 
> 2.53.0
>