> -----Original Message-----
> From: Julien Grall <jul...@xen.org>
> Sent: Tuesday, August 17, 2021 1:55 AM
> To: Penny Zheng <penny.zh...@arm.com>; xen-devel@lists.xenproject.org;
> sstabell...@kernel.org
> Cc: Bertrand Marquis <bertrand.marq...@arm.com>; Wei Chen
> <wei.c...@arm.com>; nd <n...@arm.com>
> Subject: Re: [PATCH V4 10/10] xen/arm: introduce allocate_static_memory
>
>
>
> On 16/08/2021 08:51, Penny Zheng wrote:
> >>> + d, bank, pbase, pbase + psize);
> >>> +
> >>> + /*
> >>> + * It shall be mapped to the fixed guest RAM address rambase[i],
> >>> + * And until it exhausts the ramsize[i], it will seek to the next
> >>> + * rambase[i+1].
> >>> + */
> >>> + while ( 1 )
> >>> + {
> >>> + /*
> >>> + * The current physical bank is fully mapped.
> >>> + * Handle the next physical bank.
> >>> + */
> >>> + if ( gsize >= psize )
> >>> + {
> >>> + if ( !append_static_memory_to_bank(d, &kinfo-
> >mem.bank[gbank],
> >>> + smfn, psize) )
> >>> + goto fail;
> >>> +
> >>> + gsize = gsize - psize;
> >>> + bank++;
> >>> + break;
> >>> + }
> >>> + /*
> >>> + * Current guest bank memory is not enough to map.
> >>> + * Check if we have another guest bank available.
> >>> + * gbank refers guest memory bank index.
> >>> + */
> >>> + else if ( (gbank + 2) > GUEST_RAM_BANKS ) {
> >>
> >> I don't understand the +2. Can you clarify it?
> >>
> >
> > gbank refers to the index of the guest bank, and here since current guest
> bank(gbank)
> > memory is not enough to map, users seeks to the next one(gbank + 1),
> >
> > gbank + 2 is the number of requested guest memory banks right now, and
> > shall not be larger than GUEST_RAM_BANKS.
>
> Thanks for the clarification. When I read "2" I tend to think we are checking
> the bank after the next. How about writing:
>
> (gbank + 1) >= GUEST_RAM_BANKS
>
> or
>
> gbank >= (GUEST_RAM_BANKS - 1)
>
> This as the same end results, but we check the index rather than the number of
> banks.
>
> Anyway, I can settle with 2 if you really prefer it.
>
Nah, I'll take your suggestion. Yours is more generic.
> Cheers,
>
> --
> Julien Grall
