From: Gerd Hoffmann <kraxel@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/5] virtio-pci: ignore unaligned read/write in virtio_address_space_read()/write()
Date: Mon, 13 Jul 2015 09:53:43 +0200 [thread overview]
Message-ID: <1436774023.26533.5.camel@redhat.com> (raw)
In-Reply-To: <20150713102533-mutt-send-email-mst@redhat.com>
On Mo, 2015-07-13 at 10:36 +0300, Michael S. Tsirkin wrote:
> On Mon, Jul 13, 2015 at 01:46:47PM +0800, Jason Wang wrote:
> > We abort on unaligned read/write in
> > virtio_address_space_read()/write() but since len in under control of
> > guest so qemu will simply crash when booting a modern guest (guest is
> > try to read when len is zero).
> > read.
>
> How can len be 0? Isn't this a guest bug? Or is this
> a theoretical issue?
Something dumping pci config space?
With pci access capability not being used before and therefore zeroed?
Then hitting the "data" field will trigger a zero-length read.
That assert actually triggers when booting a recent linux kernel with
disable-modern=off
cheers,
Gerd
next prev parent reply other threads:[~2015-07-13 7:53 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-13 5:46 [Qemu-devel] [PATCH 1/5] virtio-pci: ignore unaligned read/write in virtio_address_space_read()/write() Jason Wang
2015-07-13 5:46 ` [Qemu-devel] [PATCH 2/5] virtio-blk: disable scsi passthrough for 1.0 device Jason Wang
2015-07-13 7:46 ` Michael S. Tsirkin
2015-07-13 9:00 ` Jason Wang
2015-07-13 9:56 ` Kevin Wolf
2015-07-13 11:51 ` Cornelia Huck
2015-07-13 12:22 ` Michael S. Tsirkin
2015-07-13 12:30 ` Cornelia Huck
2015-07-13 12:36 ` Michael S. Tsirkin
2015-07-13 13:20 ` Cornelia Huck
2015-07-13 14:34 ` Paolo Bonzini
2015-07-13 14:41 ` Cornelia Huck
2015-07-13 15:13 ` Paolo Bonzini
2015-07-13 15:35 ` Michael S. Tsirkin
2015-07-14 17:43 ` Cornelia Huck
2015-07-15 10:59 ` Michael S. Tsirkin
2015-07-15 11:46 ` Cornelia Huck
2015-07-15 12:01 ` Michael S. Tsirkin
2015-07-15 12:43 ` Cornelia Huck
2015-07-15 13:16 ` Michael S. Tsirkin
2015-07-15 13:40 ` Cornelia Huck
2015-07-15 14:11 ` Michael S. Tsirkin
2015-07-15 14:30 ` Cornelia Huck
2015-07-15 14:39 ` Michael S. Tsirkin
2015-07-15 15:38 ` Cornelia Huck
2015-07-15 18:51 ` Michael S. Tsirkin
2015-07-16 12:37 ` Cornelia Huck
2015-07-16 12:47 ` Michael S. Tsirkin
2015-07-16 17:22 ` Paolo Bonzini
2015-07-17 7:18 ` Cornelia Huck
2015-07-13 11:27 ` Michael S. Tsirkin
2015-07-13 5:46 ` [Qemu-devel] [PATCH 3/5] virtio-blk: set VIRTIO_F_ANY_LAYOUT when 1.0 is supported Jason Wang
2015-07-13 5:46 ` [Qemu-devel] [PATCH 4/5] Revert "virtio-net: enable virtio 1.0" Jason Wang
2015-07-13 6:16 ` Cornelia Huck
2015-07-13 7:22 ` Michael S. Tsirkin
2015-07-13 8:46 ` Cornelia Huck
2015-07-13 8:29 ` Jason Wang
2015-07-13 5:46 ` [Qemu-devel] [PATCH 5/5] virtio-net: unbreak any layout Jason Wang
2015-07-13 6:50 ` Paolo Bonzini
2015-07-13 8:30 ` Jason Wang
2015-07-13 7:24 ` Michael S. Tsirkin
2015-07-13 8:22 ` Michael S. Tsirkin
2015-07-13 10:54 ` Greg Kurz
2015-07-13 11:13 ` Michael S. Tsirkin
2015-07-13 8:30 ` Jason Wang
2015-07-13 7:36 ` [Qemu-devel] [PATCH 1/5] virtio-pci: ignore unaligned read/write in virtio_address_space_read()/write() Michael S. Tsirkin
2015-07-13 7:53 ` Gerd Hoffmann [this message]
2015-07-13 8:00 ` Michael S. Tsirkin
2015-07-13 8:39 ` Gerd Hoffmann
2015-07-13 8:37 ` Jason Wang
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