From: Gerd Hoffmann <kraxel@redhat.com>
To: P J P <ppandit@redhat.com>
Cc: Ren Ding <rding@gatech.edu>, Yi Ren <c4tren@gmail.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Hanqing Zhao <hanqing@gatech.edu>
Subject: Re: [PATCH] ati-vga: increment mm_index in ati_mm_read/write
Date: Wed, 3 Jun 2020 17:32:13 +0200 [thread overview]
Message-ID: <20200603153213.pqlyti3ghvthzign@sirius.home.kraxel.org> (raw)
In-Reply-To: <nycvar.YSQ.7.77.849.2006031952260.62159@xnncv>
On Wed, Jun 03, 2020 at 08:05:50PM +0530, P J P wrote:
> +-- On Wed, 3 Jun 2020, Gerd Hoffmann wrote --+
> | Hmm, why modify mm_index? Shouldn't we just check it is non-zero
> | before calling ati_mm_read/ati_mm_write?
>
> if (s->regs.mm_index & BIT(31)) {
> ...
> } else {
} else if (s->regs.mm_index > 3) {
> ati_mm_write(s, s->regs.mm_index + addr - MM_DATA, data, size);
> }
>
> Exit condition for recursion is to set (mm_index & BIT(31)), so recursion
> would continue even with non-zero values I think.
It's wrapped into a case switch for all the registers. The code quoted
above is only entered for "addr >= MM_DATA && addr <= MM_DATA+3", so the
check should stop recursion. A less strict "s->regs.mm_index > 0" may
recurse a few times but will not recurse endless either.
cheers,
Gerd
next prev parent reply other threads:[~2020-06-03 15:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 12:47 [PATCH] ati-vga: increment mm_index in ati_mm_read/write P J P
2020-06-03 13:44 ` Gerd Hoffmann
2020-06-03 13:56 ` BALATON Zoltan
2020-06-03 14:35 ` P J P
2020-06-03 15:32 ` Gerd Hoffmann [this message]
2020-06-03 15:38 ` BALATON Zoltan
2020-06-03 15:43 ` BALATON Zoltan
2020-06-03 19:08 ` P J P
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