Re: [PATCH] crypto: ccp: Add support for SEV-ES to the PSP driver

[Tom Lendacky]

On 4/21/20 7:33 AM, Joerg Roedel wrote:
> Hi Tom,
>
> On Mon, Apr 20, 2020 at 02:54:58PM -0500, Tom Lendacky wrote:
> >   static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
> >   {
> >   	struct sev_device *sev = psp_master->sev_data;
> > @@ -214,6 +226,21 @@ static int __sev_platform_init_locked(int *error)
> >   	if (sev->state == SEV_STATE_INIT)
> >   		return 0;
> >   
> > +	if (sev_es_tmr) {
> > +		u64 tmr_pa;
> > +
> > +		/*
> > +		 * Do not include the encryption mask on the physical
> > +		 * address of the TMR (firmware should clear it anyway).
> > +		 */
> > +		tmr_pa = __pa(sev_es_tmr);
> > +		tmr_pa = ALIGN(tmr_pa, SEV_ES_TMR_ALIGN);
>
> No need to manually align the region, see below.
>
> > +	/* Obtain the TMR memory area for SEV-ES use */
> > +	tmr_page = alloc_pages(GFP_KERNEL, get_order(SEV_ES_TMR_LEN));
> > +	if (tmr_page) {
> > +		sev_es_tmr = page_address(tmr_page);
> > +	} else {
> > +		sev_es_tmr = NULL;
> > +		dev_warn(sev->dev,
> > +			 "SEV: TMR allocation failed, SEV-ES support unavailable\n");
> > +	}
>
> This allocates a 2M region where 1M is needed. The page allocator gives
> you naturally aligned region for any allocation order, so when you
> allocate 1M, it will automatically be 1M aligned.

Ah, I did not realize that. I'll update the patch to allocate just 1M then.

Thanks,
Tom

> Other than that this patch looks good to me.
>
> Regards,
>
> 	Joerg