From: "Michael S. Tsirkin" <mst@redhat.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Greg Kurz <groug@kaod.org>,
imammedo@redhat.com, bharata@linux.vnet.ibm.com,
qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
david@gibson.dropbear.id.au
Subject: Re: [Qemu-devel] QEMU terminates during reboot after memory unplug with vhost=on
Date: Thu, 16 Nov 2017 18:17:16 +0200 [thread overview]
Message-ID: <20171116181556-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20171116090448.4d53ac71@t450s.home>
On Thu, Nov 16, 2017 at 09:04:48AM -0700, Alex Williamson wrote:
> > Range is unmapped by listener but device has not been reset yet,
> > so it will get errors when attempting to access guest RAM.
>
> So IOMMU faults would occur if the device continues to try to DMA
> into that range. Sloppy ordering, but vfio wouldn't have any way to
> tell the difference between this and a runtime RAM unplug.
It's clear vfio won't be able to tell the difference, but
the device will as RAM unplug involves guest coordinating
with the device to avoid addressing the removed memory.
--
MST
next prev parent reply other threads:[~2017-11-16 16:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-16 12:23 [Qemu-devel] QEMU terminates during reboot after memory unplug with vhost=on Greg Kurz
2017-11-16 15:28 ` Michael S. Tsirkin
2017-11-16 15:34 ` Greg Kurz
2017-11-16 15:53 ` Alex Williamson
2017-11-16 15:59 ` Michael S. Tsirkin
2017-11-16 16:04 ` Alex Williamson
2017-11-16 16:17 ` Michael S. Tsirkin [this message]
-- strict thread matches above, loose matches on Subject: below --
2017-09-14 7:01 Bharata B Rao
2017-09-14 8:00 ` Igor Mammedov
2017-09-14 8:18 ` Bharata B Rao
2017-09-14 8:59 ` Igor Mammedov
2017-09-14 10:20 ` Bharata B Rao
2017-10-16 10:08 ` Bharata B Rao
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