From: Christoph Hellwig <hch@lst.de>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>,
Christoph Hellwig <hch@lst.de>, Jason Wang <jasowang@redhat.com>,
virtualization@lists.linux-foundation.org,
linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
David Gibson <david@gibson.dropbear.id.au>,
Alexey Kardashevskiy <aik@linux.ibm.com>,
Paul Mackerras <paulus@ozlabs.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Ram Pai <linuxram@us.ibm.com>,
Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Subject: Re: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
Date: Tue, 5 Feb 2019 08:24:07 +0100 [thread overview]
Message-ID: <20190205072407.GA4311@lst.de> (raw)
In-Reply-To: <20190204152416-mutt-send-email-mst@kernel.org>
On Mon, Feb 04, 2019 at 04:38:21PM -0500, Michael S. Tsirkin wrote:
> It was designed to make, when set, as many guests as we can work
> correctly, and it seems to be successful in doing exactly that.
>
> Unfortunately there could be legacy guests that do work correctly but
> become slow. Whether trying to somehow work around that
> can paint us into a corner where things again don't
> work for some people is a question worth discussing.
The other problem is that some qemu machines just throw passthrough
devices and virtio devices on the same virtual PCI(e) bus, and have a
common IOMMU setup for the whole bus / root port / domain. I think
this is completely bogus, but unfortunately it is out in the field.
Given that power is one of these examples I suspect that is what
Thiago referes to. But in this case the answer can't be that we
pile on hack ontop of another, but instead introduce a new qemu
machine that separates these clearly, and make that mandatory for
the secure guest support.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
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,
iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org,
Christoph Hellwig <hch@lst.de>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
Date: Tue, 5 Feb 2019 08:24:07 +0100 [thread overview]
Message-ID: <20190205072407.GA4311@lst.de> (raw)
In-Reply-To: <20190204152416-mutt-send-email-mst@kernel.org>
On Mon, Feb 04, 2019 at 04:38:21PM -0500, Michael S. Tsirkin wrote:
> It was designed to make, when set, as many guests as we can work
> correctly, and it seems to be successful in doing exactly that.
>
> Unfortunately there could be legacy guests that do work correctly but
> become slow. Whether trying to somehow work around that
> can paint us into a corner where things again don't
> work for some people is a question worth discussing.
The other problem is that some qemu machines just throw passthrough
devices and virtio devices on the same virtual PCI(e) bus, and have a
common IOMMU setup for the whole bus / root port / domain. I think
this is completely bogus, but unfortunately it is out in the field.
Given that power is one of these examples I suspect that is what
Thiago referes to. But in this case the answer can't be that we
pile on hack ontop of another, but instead introduce a new qemu
machine that separates these clearly, and make that mandatory for
the secure guest support.
next prev parent reply other threads:[~2019-02-05 7:24 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 [this message]
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
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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