From: "Michael S. Tsirkin" <mst@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Ram Pai <linuxram@us.ibm.com>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
virtualization@lists.linux-foundation.org,
linuxppc-devel@lists.ozlabs.org,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Jason Wang <jasowang@redhat.com>,
David Gibson <david@gibson.dropbear.id.au>,
Alexey Kardashevskiy <aik@linux.ibm.com>,
Paul Mackerras <paulus@ozlabs.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
Date: Sun, 11 Aug 2019 04:42:38 -0400 [thread overview]
Message-ID: <20190811041636-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20190811055607.GA12488@lst.de>
On Sun, Aug 11, 2019 at 07:56:07AM +0200, Christoph Hellwig wrote:
> And once again this is entirely going in the wrong direction. The only
> way using the DMA API is going to work at all is if the device is ready
> for it.
So the point made is that if DMA addresses are also physical addresses
(not necessarily the same physical addresses that driver supplied), then
DMA API actually works even though device itself uses CPU page tables.
To put it in other terms: it would be possible to make all or part of
memory unenecrypted and then have virtio access all of it. SEV guests
at the moment make a decision to instead use a bounce buffer, forcing an
extra copy but gaining security.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Jason Wang <jasowang@redhat.com>,
Alexey Kardashevskiy <aik@linux.ibm.com>,
Ram Pai <linuxram@us.ibm.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Paul Mackerras <paulus@ozlabs.org>,
iommu@lists.linux-foundation.org,
linuxppc-devel@lists.ozlabs.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
Date: Sun, 11 Aug 2019 04:42:38 -0400 [thread overview]
Message-ID: <20190811041636-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20190811055607.GA12488@lst.de>
On Sun, Aug 11, 2019 at 07:56:07AM +0200, Christoph Hellwig wrote:
> And once again this is entirely going in the wrong direction. The only
> way using the DMA API is going to work at all is if the device is ready
> for it.
So the point made is that if DMA addresses are also physical addresses
(not necessarily the same physical addresses that driver supplied), then
DMA API actually works even though device itself uses CPU page tables.
To put it in other terms: it would be possible to make all or part of
memory unenecrypted and then have virtio access all of it. SEV guests
at the moment make a decision to instead use a bounce buffer, forcing an
extra copy but gaining security.
--
MST
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-08-11 8:42 UTC|newest]
Thread overview: 198+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 17:08 [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted Thiago Jung Bauermann
2019-01-29 17:08 ` Thiago Jung Bauermann
2019-01-29 17:42 ` Thiago Jung Bauermann
2019-01-29 17:42 ` Thiago Jung Bauermann
2019-01-29 19:02 ` Michael S. Tsirkin
2019-01-29 19:02 ` Michael S. Tsirkin
2019-01-30 2:24 ` Jason Wang
2019-01-30 2:24 ` Jason Wang
2019-01-30 2:36 ` Michael S. Tsirkin
2019-01-30 2:36 ` Michael S. Tsirkin
2019-01-30 2:36 ` Michael S. Tsirkin
2019-01-30 3:05 ` Jason Wang
2019-01-30 3:05 ` Jason Wang
2019-01-30 3:05 ` Jason Wang
2019-01-30 3:26 ` Michael S. Tsirkin
2019-01-30 3:26 ` Michael S. Tsirkin
2019-01-30 3:26 ` Michael S. Tsirkin
2019-01-30 7:44 ` Christoph Hellwig
2019-01-30 7:44 ` Christoph Hellwig
2019-01-30 7:44 ` Christoph Hellwig
2019-02-04 18:15 ` Thiago Jung Bauermann
2019-02-04 18:15 ` Thiago Jung Bauermann
2019-02-04 18:15 ` Thiago Jung Bauermann
2019-02-04 21:38 ` Michael S. Tsirkin
2019-02-04 21:38 ` Michael S. Tsirkin
2019-02-05 7:24 ` Christoph Hellwig
2019-02-05 7:24 ` Christoph Hellwig
2019-02-05 16:13 ` Michael S. Tsirkin
2019-02-05 16:13 ` Michael S. Tsirkin
2019-02-05 16:13 ` Michael S. Tsirkin
2019-02-05 16:13 ` Michael S. Tsirkin
2019-02-05 7:24 ` Christoph Hellwig
2019-02-04 21:38 ` Michael S. Tsirkin
2019-03-26 16:53 ` Michael S. Tsirkin
2019-03-26 16:53 ` Michael S. Tsirkin
2019-03-26 16:53 ` Michael S. Tsirkin
2019-01-30 2:24 ` Jason Wang
2019-02-04 18:14 ` Thiago Jung Bauermann
2019-02-04 18:14 ` Thiago Jung Bauermann
2019-02-04 18:14 ` Thiago Jung Bauermann
2019-02-04 20:23 ` Michael S. Tsirkin
2019-02-04 20:23 ` Michael S. Tsirkin
2019-03-20 16:13 ` Thiago Jung Bauermann
2019-03-20 16:13 ` Thiago Jung Bauermann
2019-03-20 16:13 ` Thiago Jung Bauermann
2019-03-20 21:17 ` Michael S. Tsirkin
2019-03-20 21:17 ` Michael S. Tsirkin
2019-03-20 21:17 ` Michael S. Tsirkin
2019-03-22 0:05 ` Thiago Jung Bauermann
2019-03-22 0:05 ` Thiago Jung Bauermann
2019-03-22 0:05 ` Thiago Jung Bauermann
2019-03-23 21:01 ` Michael S. Tsirkin
2019-03-23 21:01 ` Michael S. Tsirkin
2019-03-23 21:01 ` Michael S. Tsirkin
2019-03-25 0:57 ` David Gibson
2019-03-25 0:57 ` David Gibson
2019-03-25 0:57 ` David Gibson
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-17 21:42 ` Thiago Jung Bauermann
2019-04-19 23:09 ` Michael S. Tsirkin
2019-04-19 23:09 ` Michael S. Tsirkin
2019-04-19 23:09 ` Michael S. Tsirkin
2019-04-19 23:09 ` Michael S. Tsirkin
2019-04-25 1:01 ` Thiago Jung Bauermann
2019-04-25 1:01 ` Thiago Jung Bauermann
2019-04-25 1:01 ` Thiago Jung Bauermann
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-25 1:18 ` Michael S. Tsirkin
2019-04-26 23:56 ` Thiago Jung Bauermann
2019-04-26 23:56 ` Thiago Jung Bauermann
2019-04-26 23:56 ` Thiago Jung Bauermann
2019-04-26 23:56 ` Thiago Jung Bauermann
2019-05-20 13:08 ` Michael S. Tsirkin
2019-05-20 13:08 ` Michael S. Tsirkin
2019-05-20 13:08 ` Michael S. Tsirkin
2019-05-20 13:08 ` Michael S. Tsirkin
2019-04-25 1:01 ` Thiago Jung Bauermann
2019-05-20 13:16 ` Michael S. Tsirkin
2019-05-20 13:16 ` Michael S. Tsirkin
2019-05-20 13:16 ` Michael S. Tsirkin
2019-05-20 13:16 ` Michael S. Tsirkin
2019-06-04 1:13 ` Thiago Jung Bauermann
2019-06-04 1:13 ` Thiago Jung Bauermann
2019-06-04 1:13 ` Thiago Jung Bauermann
2019-06-04 1:42 ` Michael S. Tsirkin
2019-06-04 1:42 ` Michael S. Tsirkin
2019-06-04 1:42 ` Michael S. Tsirkin
2019-06-04 1:42 ` Michael S. Tsirkin
2019-06-28 1:58 ` Thiago Jung Bauermann
2019-06-28 1:58 ` Thiago Jung Bauermann
2019-06-28 1:58 ` Thiago Jung Bauermann
2019-06-28 1:58 ` Thiago Jung Bauermann
2019-07-01 14:17 ` Michael S. Tsirkin
2019-07-01 14:17 ` Michael S. Tsirkin
2019-07-01 14:17 ` Michael S. Tsirkin
2019-07-01 14:17 ` Michael S. Tsirkin
2019-07-14 5:51 ` Thiago Jung Bauermann
2019-07-14 5:51 ` Thiago Jung Bauermann
2019-07-14 5:51 ` Thiago Jung Bauermann
2019-07-14 5:51 ` Thiago Jung Bauermann
2019-07-15 14:35 ` Michael S. Tsirkin
2019-07-15 14:35 ` Michael S. Tsirkin
2019-07-15 14:35 ` Michael S. Tsirkin
2019-07-15 14:35 ` Michael S. Tsirkin
2019-07-15 20:29 ` Thiago Jung Bauermann
2019-07-15 20:29 ` Thiago Jung Bauermann
2019-07-15 20:29 ` Thiago Jung Bauermann
2019-07-15 20:36 ` Michael S. Tsirkin
2019-07-15 20:36 ` Michael S. Tsirkin
2019-07-15 20:36 ` Michael S. Tsirkin
2019-07-15 20:36 ` Michael S. Tsirkin
2019-07-15 22:03 ` Thiago Jung Bauermann
2019-07-15 22:03 ` Thiago Jung Bauermann
2019-07-15 22:03 ` Thiago Jung Bauermann
2019-07-15 22:03 ` Thiago Jung Bauermann
2019-07-15 22:16 ` Michael S. Tsirkin
2019-07-15 22:16 ` Michael S. Tsirkin
2019-07-15 22:16 ` Michael S. Tsirkin
2019-07-15 22:16 ` Michael S. Tsirkin
2019-07-15 23:05 ` Thiago Jung Bauermann
2019-07-15 23:05 ` Thiago Jung Bauermann
2019-07-15 23:05 ` Thiago Jung Bauermann
2019-07-15 23:05 ` Thiago Jung Bauermann
2019-07-15 23:24 ` Benjamin Herrenschmidt
2019-07-15 23:24 ` Benjamin Herrenschmidt
2019-07-15 23:24 ` Benjamin Herrenschmidt
2019-07-15 23:24 ` Benjamin Herrenschmidt
2019-07-15 20:29 ` Thiago Jung Bauermann
2019-07-18 3:39 ` Thiago Jung Bauermann
2019-07-18 3:39 ` Thiago Jung Bauermann
2019-07-18 3:39 ` Thiago Jung Bauermann
2019-06-04 1:13 ` Thiago Jung Bauermann
2019-03-20 16:13 ` Thiago Jung Bauermann
2019-02-04 20:23 ` Michael S. Tsirkin
2019-01-29 19:02 ` Michael S. Tsirkin
2019-01-29 17:42 ` Thiago Jung Bauermann
2019-08-10 18:57 ` Michael S. Tsirkin
2019-08-10 18:57 ` Michael S. Tsirkin
2019-08-10 18:57 ` Michael S. Tsirkin
2019-08-10 22:07 ` Ram Pai
2019-08-10 22:07 ` Ram Pai
2019-08-10 22:07 ` Ram Pai
2019-08-11 5:56 ` Christoph Hellwig
2019-08-11 5:56 ` Christoph Hellwig
2019-08-11 5:56 ` Christoph Hellwig
2019-08-11 6:46 ` Ram Pai
2019-08-11 6:46 ` Ram Pai
2019-08-11 6:46 ` Ram Pai
2019-08-11 8:44 ` Michael S. Tsirkin
2019-08-11 8:44 ` Michael S. Tsirkin
2019-08-11 8:44 ` Michael S. Tsirkin
2019-08-12 12:13 ` Christoph Hellwig
2019-08-12 12:13 ` Christoph Hellwig
2019-08-12 12:13 ` Christoph Hellwig
2019-08-12 20:29 ` Ram Pai
2019-08-12 20:29 ` Ram Pai
2019-08-12 20:29 ` Ram Pai
2019-08-11 8:42 ` Michael S. Tsirkin [this message]
2019-08-11 8:42 ` Michael S. Tsirkin
2019-08-11 8:42 ` Michael S. Tsirkin
2019-08-11 8:55 ` Michael S. Tsirkin
2019-08-11 8:55 ` Michael S. Tsirkin
2019-08-11 8:55 ` Michael S. Tsirkin
2019-08-12 12:15 ` Christoph Hellwig
2019-08-12 12:15 ` Christoph Hellwig
2019-08-12 12:15 ` Christoph Hellwig
2019-09-06 5:07 ` Michael S. Tsirkin
2019-09-06 5:07 ` Michael S. Tsirkin
2019-09-06 5:07 ` Michael S. Tsirkin
2019-08-12 9:51 ` David Gibson
2019-08-12 9:51 ` David Gibson
2019-08-12 9:51 ` David Gibson
2019-08-13 13:26 ` Christoph Hellwig
2019-08-13 13:26 ` Christoph Hellwig
2019-08-13 14:24 ` David Gibson
2019-08-13 14:24 ` David Gibson
2019-08-13 15:45 ` Ram Pai
2019-08-13 15:45 ` Ram Pai
2019-08-13 15:45 ` Ram Pai
2019-08-26 17:48 ` Ram Pai
2019-08-26 17:48 ` Ram Pai
2019-08-26 17:48 ` Ram Pai
2019-08-13 14:24 ` David Gibson
2019-08-13 13:26 ` Christoph Hellwig
2019-08-11 8:12 ` Michael S. Tsirkin
2019-08-11 8:12 ` Michael S. Tsirkin
2019-08-11 8:12 ` Michael S. Tsirkin
-- strict thread matches above, loose matches on Subject: below --
2019-01-29 17:08 Thiago Jung Bauermann
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