From: Jan Kara <jack@suse.cz>
To: Dave Chinner <david@fromorbit.com>
Cc: Pankaj Gupta <pagupta@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
qemu-devel@nongnu.org, linux-nvdimm@ml01.01.org,
linux-fsdevel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-acpi@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, jack@suse.cz, stefanha@redhat.com,
dan.j.williams@intel.com, riel@surriel.com, nilal@redhat.com,
kwolf@redhat.com, pbonzini@redhat.com, zwisler@kernel.org,
vishal.l.verma@intel.com, dave.jiang@intel.com, david@redhat.com,
jmoyer@redhat.com, xiaoguangrong.eric@gmail.com,
hch@infradead.org, mst@redhat.com, jasowang@redhat.com,
lcapitulino@redhat.com, imammedo@redhat.com, eblake@redhat.com,
willy@infradead.org, tytso@mit.edu, adilger.kernel@dilger.ca,
darrick.wong@oracle.com, rjw@rjwysocki.net
Subject: Re: [PATCH v3 0/5] kvm "virtio pmem" device
Date: Thu, 10 Jan 2019 11:17:57 +0100 [thread overview]
Message-ID: <20190110101757.GC15790@quack2.suse.cz> (raw)
In-Reply-To: <20190110012617.GA4205@dastard>
On Thu 10-01-19 12:26:17, Dave Chinner wrote:
> On Wed, Jan 09, 2019 at 08:17:31PM +0530, Pankaj Gupta wrote:
> > This patch series has implementation for "virtio pmem".
> > "virtio pmem" is fake persistent memory(nvdimm) in guest
> > which allows to bypass the guest page cache. This also
> > implements a VIRTIO based asynchronous flush mechanism.
>
> Hmmmm. Sharing the host page cache direct into the guest VM. Sounds
> like a good idea, but.....
>
> This means the guest VM can now run timing attacks to observe host
> side page cache residency, and depending on the implementation I'm
> guessing that the guest will be able to control host side page
> cache eviction, too (e.g. via discard or hole punch operations).
>
> Which means this functionality looks to me like a new vector for
> information leakage into and out of the guest VM via guest
> controlled host page cache manipulation.
>
> https://arxiv.org/pdf/1901.01161
>
> I might be wrong, but if I'm not we're going to have to be very
> careful about how guest VMs can access and manipulate host side
> resources like the page cache.....
Right. Thinking about this I would be more concerned about the fact that
guest can effectively pin amount of host's page cache upto size of the
device/file passed to guest as PMEM, can't it Pankaj? Or is there some QEMU
magic that avoids this?
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-01-10 10:18 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 14:47 [PATCH v3 0/5] kvm "virtio pmem" device Pankaj Gupta
2019-01-09 14:47 ` [PATCH v3 1/5] libnvdimm: nd_region flush callback support Pankaj Gupta
2019-01-09 14:47 ` [PATCH v3 2/5] virtio-pmem: Add virtio pmem driver Pankaj Gupta
2019-01-14 15:54 ` Michael S. Tsirkin
2019-01-15 6:33 ` Pankaj Gupta
2019-01-09 14:47 ` [PATCH v3 3/5] libnvdimm: add nd_region buffered dax_dev flag Pankaj Gupta
2019-01-09 14:47 ` [PATCH v3 4/5] ext4: disable map_sync for virtio pmem Pankaj Gupta
2019-01-09 14:47 ` [PATCH v3 5/5] xfs: " Pankaj Gupta
2019-01-09 16:26 ` Darrick J. Wong
2019-01-09 18:08 ` Pankaj Gupta
2019-01-10 1:26 ` [PATCH v3 0/5] kvm "virtio pmem" device Dave Chinner
2019-01-10 2:40 ` Rik van Riel
2019-01-10 10:17 ` Jan Kara [this message]
2019-01-13 1:38 ` Pankaj Gupta
2019-01-13 1:43 ` Dan Williams
2019-01-13 2:17 ` [Qemu-devel] " Pankaj Gupta
2019-01-14 9:55 ` Jan Kara
2019-01-14 10:16 ` Pankaj Gupta
2019-01-11 7:45 ` Pankaj Gupta
2019-01-13 23:29 ` Dave Chinner
2019-01-13 23:38 ` Matthew Wilcox
2019-01-14 2:50 ` Dave Chinner
2019-01-14 7:15 ` Pankaj Gupta
2019-01-14 21:25 ` Dave Chinner
2019-01-14 21:35 ` Dan Williams
2019-01-14 22:21 ` Dave Chinner
2019-01-15 2:19 ` Michael S. Tsirkin
2019-01-15 5:37 ` [Qemu-devel] " Pankaj Gupta
2019-01-15 5:35 ` Pankaj Gupta
2019-01-15 20:42 ` Dave Chinner
2019-02-04 22:56 ` security implications of caching with virtio pmem (was Re: [PATCH v3 0/5] kvm "virtio pmem" device) Michael S. Tsirkin
2019-02-05 7:29 ` [Qemu-devel] " Pankaj Gupta
2019-02-06 14:00 ` David Hildenbrand
2019-02-06 18:01 ` Michael S. Tsirkin
2019-02-11 7:29 ` [Qemu-devel] " Pankaj Gupta
2019-02-11 22:29 ` Dave Chinner
2019-02-11 22:58 ` David Hildenbrand
2019-02-11 23:07 ` Michael S. Tsirkin
-- strict thread matches above, loose matches on Subject: below --
2019-01-09 13:50 [PATCH v3 0/5] kvm "virtio pmem" device Pankaj Gupta
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