Re: [PATCH v9 06/27] x86/fpu/xstate: Create guest fpstate with guest specific config

[Yang, Weijiang]

On 1/30/2024 9:38 AM, Edgecombe, Rick P wrote:
> On Tue, 2024-01-23 at 18:41 -0800, Yang Weijiang wrote:
> > -bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
> > +static struct fpstate *__fpu_alloc_init_guest_fpstate(struct
> > fpu_guest *gfpu)
> >   {
> >          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);
> Minor, I'm not sure the extra char warrants changing it to a wrapped
> line, but that's just my personal opinion.
>
> > +
> >          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           = fpu_guest_cfg.default_size;
> > +       fpstate->xfeatures      = fpu_guest_cfg.default_features;
> > +       fpstate->user_size      = fpu_user_cfg.default_size;
> > +       fpstate->user_xfeatures = fpu_user_cfg.default_features;
> > +       fpstate->xfd            = 0;
> >   
> > -       /* Leave xfd to 0 (the reset value defined by spec) */
> > -       __fpstate_reset(fpstate, 0);
> >          fpstate_init_user(fpstate);
> >          fpstate->is_valloc      = true;
> >          fpstate->is_guest       = true;
> >   
> >          gfpu->fpstate           = fpstate;
> > -       gfpu->xfeatures         = fpu_user_cfg.default_features;
> > -       gfpu->perm              = fpu_user_cfg.default_features;
> > +       gfpu->xfeatures         = fpu_guest_cfg.default_features;
> > +       gfpu->perm              = fpu_guest_cfg.default_features;
> > +
> > +       return fpstate;
> > +}
> > +
> > +bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
> > +{
> > +       struct fpstate *fpstate;
> > +
> > +       fpstate = __fpu_alloc_init_guest_fpstate(gfpu);
> The above two statements could be just one line and still even fit
> under 80 chars.

Indeed, the variable is redundant, I'll remove it, thanks!

> All the same,
>
> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
>
> > +
> > +       if (!fpstate)
> > +               return false;
> >