Re: [PATCH v8 06/26] x86/fpu/xstate: Create guest fpstate with guest specific config

[Yang, Weijiang]

On 1/5/2024 6:47 AM, Edgecombe, Rick P wrote:
> On Thu, 2023-12-21 at 09:02 -0500, Yang Weijiang wrote:
> > +static struct fpstate *__fpu_alloc_init_guest_fpstate(struct
> > fpu_guest *gfpu)
> >   {
> > +       bool compacted = cpu_feature_enabled(X86_FEATURE_XCOMPACTED);
> > +       unsigned int gfpstate_size, size;
> >          struct fpstate *fpstate;
> > -       unsigned int size;
> >   
> > -       size = fpu_user_cfg.default_size + ALIGN(offsetof(struct
> > fpstate, regs), 64);
> > +       /*
> > +        * fpu_guest_cfg.default_size is initialized to hold all
> > enabled
> > +        * xfeatures except the user dynamic xfeatures. If the user
> > dynamic
> > +        * xfeatures are enabled, the guest fpstate will be re-
> > allocated to
> > +        * hold all guest enabled xfeatures, so omit user dynamic
> > xfeatures
> > +        * here.
> > +        */
> > +       size = fpu_guest_cfg.default_size +
> > +              ALIGN(offsetof(struct fpstate, regs), 64);
> > +
> >          fpstate = vzalloc(size);
> >          if (!fpstate)
> > -               return false;
> > +               return NULL;
> > +       /*
> > +        * Initialize sizes and feature masks, use fpu_user_cfg.*
> > +        * for user_* settings for compatibility of exiting uAPIs.
> > +        */
> > +       fpstate->size           = gfpstate_size;
> gfpstate_size is used uninitialized.

Ah, this is another unused variable after introduce fpu_guest_cfg.*, should be replaced by
fpu_guest_cfg.default_size. Thanks for caching it!