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From: Stefan Hajnoczi <stefanha@redhat.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, jcody@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH RFC 2/2] block: Warn on insecure format probing
Date: Fri, 31 Oct 2014 11:19:22 +0000	[thread overview]
Message-ID: <20141031111922.GD10332@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <87oastzprh.fsf@blackfin.pond.sub.org>

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On Thu, Oct 30, 2014 at 01:49:22PM +0100, Markus Armbruster wrote:
> Kevin Wolf <kwolf@redhat.com> writes:
> 
> > Am 29.10.2014 um 14:54 hat Markus Armbruster geschrieben:
> >> Anthony tried something similar (commit 79368c8), but couldn't get it
> >> right (commit 8b33d9e).
> >
> > The discussion back then: http://patchwork.ozlabs.org/patch/58980/
> >
> > The problem with Anthony's code was that he didn't handle a qiov
> > correctly that had unaligned members. With today's block layer, this is
> > not a big deal to implement correctly. We're running coroutines instead
> > of AIO callbacks and we don't have to do all the manual qiov fixing
> > magic that Anthony had in his patch, util/iov.c provides all you need.
> >
> > I'll send out an RFC series that implements this.
> 
> I'm strongly opposed to this idea.

Me too.  Meddling with the guest is wrong and just adds a new problem!

It is perfectly okay for backup appliances, nested virtualization, or
disk management appliances to write image format headers to raw disks.

I'm am 100% against trying to detect the guest writing image format
headers to raw disks.

Probing is not a guest problem.  It is a QEMU problem.  Fix QEMU, don't
cripple the guest.

Stefan

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  reply	other threads:[~2014-10-31 15:05 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-28 16:03 [Qemu-devel] [PATCH RFC 0/2] block: Warn on insecure format probing Markus Armbruster
2014-10-28 16:03 ` [Qemu-devel] [PATCH RFC 1/2] block: Factor bdrv_probe_all() out of find_image_format() Markus Armbruster
2014-10-28 16:34   ` Eric Blake
2014-10-28 16:41   ` Jeff Cody
2014-10-29 15:22   ` Stefan Hajnoczi
2014-10-28 16:03 ` [Qemu-devel] [PATCH RFC 2/2] block: Warn on insecure format probing Markus Armbruster
2014-10-28 17:02   ` Eric Blake
2014-10-28 18:29     ` Jeff Cody
2014-10-28 18:56       ` Eric Blake
2014-10-28 19:42         ` Jeff Cody
2014-10-29  7:36           ` Markus Armbruster
2014-10-29  8:25             ` Max Reitz
2014-10-29  7:22         ` Markus Armbruster
2014-10-30 13:58           ` Jeff Cody
2014-11-03  8:07             ` Markus Armbruster
2014-10-29  7:03     ` Markus Armbruster
2014-10-28 18:33   ` Jeff Cody
2014-10-29  6:37     ` Markus Armbruster
2014-10-30 13:52       ` Jeff Cody
2014-11-03  8:11         ` Markus Armbruster
2014-10-29  1:16   ` Fam Zheng
2014-10-29  6:32     ` Markus Armbruster
2014-10-29 10:12   ` Kevin Wolf
2014-10-29 13:54     ` Markus Armbruster
2014-10-29 15:34       ` Stefan Hajnoczi
2014-10-30  9:07         ` Markus Armbruster
2014-10-30  9:24           ` Stefan Hajnoczi
2014-10-30 12:19             ` Markus Armbruster
2014-10-30  9:30       ` Kevin Wolf
2014-10-30 12:49         ` Markus Armbruster
2014-10-31 11:19           ` Stefan Hajnoczi [this message]
2014-10-31 22:45           ` Eric Blake
2014-11-03  8:15             ` Markus Armbruster
2014-11-03 11:13             ` Kevin Wolf
2014-11-04  9:36               ` Markus Armbruster
2014-11-04 10:32                 ` Kevin Wolf
2014-11-05  7:58                   ` Markus Armbruster
2014-11-03 11:00           ` Kevin Wolf
2014-11-04  9:39             ` Markus Armbruster
2014-11-04 16:09               ` Jeff Cody
2014-11-05  8:05                 ` Markus Armbruster
2014-11-05  8:09                   ` Max Reitz
2014-10-30  9:08   ` Max Reitz
2014-10-30  9:27     ` Stefan Hajnoczi
2014-10-30  9:36       ` Kevin Wolf
2014-10-31 11:24         ` Stefan Hajnoczi
2014-10-31 11:56           ` Kevin Wolf
2014-11-03  8:54             ` Markus Armbruster
2014-11-03  9:11               ` Max Reitz
2014-11-04  9:34                 ` Markus Armbruster
2014-11-03 10:25               ` Kevin Wolf
2014-11-03 15:05                 ` Stefan Hajnoczi
2014-11-03 15:13                   ` Max Reitz
2014-11-04  9:42                   ` Markus Armbruster
2014-11-04 10:11                   ` Kevin Wolf
2014-11-04 15:25                     ` Stefan Hajnoczi
2014-11-04 15:37                       ` Kevin Wolf
2014-11-05  8:39                         ` Markus Armbruster
2014-11-05 10:18                           ` Eric Blake
2014-10-30 13:02     ` Markus Armbruster
2014-11-03  8:44       ` Max Reitz
2014-10-30 20:45   ` Richard W.M. Jones
2014-11-03  8:18     ` Markus Armbruster

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