Re: [PATCH v2 4/8] x86: rename {get,put}_user() to {get,put}_guest()

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Wed, Feb 17, 2021 at 09:21:05AM +0100, Jan Beulich wrote:
> Bring them (back) in line with __{get,put}_guest().
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

> 
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -1649,19 +1649,19 @@ static void load_segments(struct vcpu *n
>  
>              if ( !ring_1(regs) )
>              {
> -                ret  = put_user(regs->ss,       esp-1);
> -                ret |= put_user(regs->esp,      esp-2);
> +                ret  = put_guest(regs->ss,  esp - 1);
> +                ret |= put_guest(regs->esp, esp - 2);
>                  esp -= 2;
>              }
>  
>              if ( ret |
> -                 put_user(rflags,              esp-1) |
> -                 put_user(cs_and_mask,         esp-2) |
> -                 put_user(regs->eip,           esp-3) |
> -                 put_user(uregs->gs,           esp-4) |
> -                 put_user(uregs->fs,           esp-5) |
> -                 put_user(uregs->es,           esp-6) |
> -                 put_user(uregs->ds,           esp-7) )
> +                 put_guest(rflags,      esp - 1) |
> +                 put_guest(cs_and_mask, esp - 2) |
> +                 put_guest(regs->eip,   esp - 3) |
> +                 put_guest(uregs->gs,   esp - 4) |
> +                 put_guest(uregs->fs,   esp - 5) |
> +                 put_guest(uregs->es,   esp - 6) |
> +                 put_guest(uregs->ds,   esp - 7) )

I wonder whether we could use put_unsafe here, but I assume there's
some kind of speculation attack also against stores?

Thanks, Roger.