From: Paolo Bonzini <pbonzini@redhat.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
Anthony Liguori <aliguori@us.ibm.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] [PATCHv2] virtio: verify that all outstanding buffers are flushed
Date: Fri, 14 Dec 2012 02:51:02 -0500 (EST) [thread overview]
Message-ID: <563127555.23861364.1355471450321.JavaMail.root@redhat.com> (raw)
In-Reply-To: <8738z94f3d.fsf@rustcorp.com.au>
> > We technically should save the addresses and sizes too. It makes
> > it a heck of a lot safer then re-reading guest memory since we do some
> > validation on the size of the sg elements.
>
> Not really.
>
> The guest puts the descriptors in the ring and leaves them there until
> the device acks. If it changes them once they're exposed but before
> they're acked, it can get either before or after version, and always
> could.
The problems start when the guest tries to race against QEMU and defy
the validation. Always using the validated version is a bit easier
than redoing the validation after migration.
Paolo
next prev parent reply other threads:[~2012-12-14 7:51 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-12 10:51 [Qemu-devel] [PATCHv2] virtio: verify that all outstanding buffers are flushed Michael S. Tsirkin
2012-12-12 13:50 ` Stefan Hajnoczi
2012-12-12 14:01 ` Paolo Bonzini
2012-12-12 14:30 ` Michael S. Tsirkin
2012-12-12 14:36 ` Paolo Bonzini
2012-12-12 14:47 ` Michael S. Tsirkin
2012-12-12 15:01 ` Paolo Bonzini
2012-12-12 15:25 ` Michael S. Tsirkin
2012-12-12 15:52 ` Paolo Bonzini
2012-12-12 16:37 ` Michael S. Tsirkin
2012-12-12 16:51 ` Paolo Bonzini
2012-12-12 17:14 ` Michael S. Tsirkin
2012-12-12 17:39 ` Paolo Bonzini
2012-12-12 19:23 ` Michael S. Tsirkin
2012-12-12 21:00 ` Paolo Bonzini
2012-12-12 21:19 ` Michael S. Tsirkin
2012-12-12 21:33 ` Anthony Liguori
2012-12-12 21:51 ` Michael S. Tsirkin
2012-12-14 1:06 ` Rusty Russell
2012-12-14 7:51 ` Paolo Bonzini [this message]
2012-12-16 20:36 ` Anthony Liguori
2012-12-13 7:39 ` Paolo Bonzini
2012-12-13 10:48 ` Kevin Wolf
2012-12-16 16:14 ` Michael S. Tsirkin
2012-12-12 14:26 ` Michael S. Tsirkin
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