From: Kevin Wolf <kwolf@redhat.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: qemu-devel@nongnu.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [PATCH] ide: cleanup warnings
Date: Wed, 04 May 2011 16:15:32 +0200 [thread overview]
Message-ID: <4DC15F84.4030602@redhat.com> (raw)
In-Reply-To: <20110504140419.GI7838@random.random>
Am 04.05.2011 16:04, schrieb Andrea Arcangeli:
> On Wed, May 04, 2011 at 03:57:28PM +0200, Kevin Wolf wrote:
>> I can't see how you could leave ide_dma_cb without either scheduling
>> another AIO request or setting aiocb = NULL in ide_set_inactive. I guess
>> I need to reproduce this and do some debugging...
>
> That would be nice to be sure. This has been triggering on a older
> codebase, it's uncertain if this would happen with current code
> too. The \n so far was the only obvious improvement I could make to
> the upstream code, until we understand better what's going on...
>
> The good thing is it doesn't seem to cause problems, other than the
> printf. The leftover in the dma->aiocb likely gets overwritten when
> guest retries without failure.
Right. I'm not so much concerned about aiocb (though it would certainly
be cleaner if we cleared it; I think it's checked in more places), but
more about bm->status which is a guest-visible register.
On the other hand we store things in bm->status that are definitely not
meant to be guest visible, so the emulation of this register is broken
anyway. Fixing all of this might turn out to be hard if you don't want
to break migration.
Kevin
prev parent reply other threads:[~2011-05-04 14:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-03 20:03 [Qemu-devel] [PATCH] ide: cleanup warnings Andrea Arcangeli
2011-05-04 8:08 ` Kevin Wolf
2011-05-04 13:41 ` Andrea Arcangeli
2011-05-04 13:57 ` Kevin Wolf
2011-05-04 14:04 ` Andrea Arcangeli
2011-05-04 14:15 ` Kevin Wolf [this message]
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