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From: Stefan Hajnoczi <stefanha@redhat.com>
To: Ladi Prosek <lprosek@redhat.com>
Cc: qemu-devel@nongnu.org, mst@redhat.com, rkagan@virtuozzo.com
Subject: Re: [Qemu-devel] [PATCH 0/3] virtio-balloon: stats vq fixes
Date: Wed, 7 Sep 2016 14:02:15 -0400	[thread overview]
Message-ID: <20160907180215.GC18576@stefanha-x1.localdomain> (raw)
In-Reply-To: <1473261649-31465-1-git-send-email-lprosek@redhat.com>

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On Wed, Sep 07, 2016 at 05:20:46PM +0200, Ladi Prosek wrote:
> It is not
> necessary to check balloon_stats_supported. Pushing buffers without
> negotiating stats support would be a driver bug. The common codepath
> does not check it either.

This part made me nervous because QEMU is never allowed to trust the
guest - QEMU must never crash or expose information to the guest.

However this seems okay since virtqueue_rewind() on an unused virtqueue
is safe.  It will return false so we'll never actually try to access a
virtqueue that hasn't been initialized.

Stefan

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      parent reply	other threads:[~2016-09-07 18:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-07 15:20 [Qemu-devel] [PATCH 0/3] virtio-balloon: stats vq fixes Ladi Prosek
2016-09-07 15:20 ` [Qemu-devel] [PATCH 1/3] virtio-balloon: discard virtqueue element on reset Ladi Prosek
2016-09-07 17:48   ` Stefan Hajnoczi
2016-09-08  6:38   ` Roman Kagan
2016-09-07 15:20 ` [Qemu-devel] [PATCH 2/3] virtio: add virtqueue_rewind() Ladi Prosek
2016-09-08  6:44   ` Roman Kagan
2016-09-08  7:30     ` Ladi Prosek
2016-09-12  9:20       ` Stefan Hajnoczi
2016-09-07 15:20 ` [Qemu-devel] [PATCH 3/3] virtio-balloon: fix stats vq migration Ladi Prosek
2016-09-07 18:02   ` Stefan Hajnoczi
2016-09-08  6:47   ` Roman Kagan
2016-09-07 18:02 ` Stefan Hajnoczi [this message]

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