Re: [PATCH] target/i386: Treat qtest like TCG for supported-features

[Zhao Liu <zhao1.liu@intel.com>]

On Mon, Mar 30, 2026 at 04:14:37PM +0100, Peter Maydell wrote:
> Date: Mon, 30 Mar 2026 16:14:37 +0100
> From: Peter Maydell <peter.maydell@linaro.org>
> Subject: [PATCH] target/i386: Treat qtest like TCG for supported-features
> X-Mailer: git-send-email 2.43.0
> 
> In x86_cpu_get_supported_feature_word() we figure out the supported
> features differently for each accelerator. The default case is
> "set all feature bits"; however this triggers a warning because
> it enables two features which conflict with each other:
> 
> $ ./build/x86/qemu-system-x86_64   -cpu max -accel qtest -S
> qemu-system-x86_64: warning: this feature conflicts with APX: CPUID[eax=07h,ecx=00h].EBX.mpx [bit 14]
> qemu-system-x86_64: warning: this feature conflicts with MPX: CPUID[eax=07h,ecx=01h].EDX.apxf [bit 21]
> 
> Treat qtest like TCG here, to avoid the complaint.

I see, this is a proper way to resolve this for max cpu with qtest,

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

so,

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

> ---
> This suggests to me that the default case is not something
> we ever want to be in, and we should instead be exhaustively
> enumerating the accelerators and asserting if we don't know
> how to handle this for the accelerator in use. But there are
> several accelerators that we don't have code for here...

yes, when I have some time, I’d see if I can sort this out, to clarify
what accelerator needs to be covered here.

Regards,
Zhao