在 2023/10/19 上午7:47, Richard Henderson 写道:
On 10/18/23 01:59, Song Gao wrote:
Some users may not need LSX/LASX, this patch allows the user
enable/disable LSX/LASX features.
e.g
'-cpu max,lsx=on,lasx=on' (default);
'-cpu max,lsx=on,lasx=off' (enabled LSX);
'-cpu max,lsx=off,lasx=on' (error, need lsx=on);
'-cpu max,lsx=off' (disable LSX and LASX).
...
+ /* CPU has LSX */
+ bool has_lsx;
+ /* CPU has LASX */
+ bool has_lasx;
Why do you need these variables?
I suspect that you've copied them from one of the more complex Arm
cases where we need to resolve multiple properties simultaneously
during realize.
You'll get identical behaviour in your current code if you drop these
and rely only on the CPUCFG2 bits.
If you wanted to do something more complex, you could use OnOffAuto,
so that you can detect conflicting settings (such as #3 above), but
not generate an error for
-cpu foo,lasx=on
Got it, thanks for you suggestion.
where 'foo' is some cpu model which does *no* default lsx=on. You
would see that has_lsx==AUTO && has_lasx==ON and then set lsx=ON.
Some cpu model not support lasx or lsx feature, we should't allow user
set lsx=on or lasx=on.
I think we need env->features. set the feature when the cpu model
support this feature.
If the cpu model support the feature, we allow user set CPUCFG to
enable/disable this feature.
Do you have more suggestion?
Thanks.
Song Gao
