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From: Christoph Hellwig <hch@infradead.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>,
	virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	aik@ozlabs.ru, robh@kernel.org, joe@perches.com,
	elfring@users.sourceforge.net, david@gibson.dropbear.id.au,
	jasowang@redhat.com, benh@kernel.crashing.org,
	mpe@ellerman.id.au, mst@redhat.com, hch@infradead.org,
	linuxram@us.ibm.com, haren@linux.vnet.ibm.com, paulus@samba.org,
	srikar@linux.vnet.ibm.com, robin.murphy@arm.com,
	jean-philippe.brucker@arm.com, marc.zyngier@arm.com
Subject: Re: [RFC 0/4] Virtio uses DMA API for all devices
Date: Mon, 30 Jul 2018 02:34:14 -0700	[thread overview]
Message-ID: <20180730093414.GD26245@infradead.org> (raw)
In-Reply-To: <20180727095804.GA25592@arm.com>

On Fri, Jul 27, 2018 at 10:58:05AM +0100, Will Deacon wrote:
> 
> I just wanted to say that this patch series provides a means for us to
> force the coherent DMA ops for legacy virtio devices on arm64, which in turn
> means that we can enable the SMMU with legacy devices in our fastmodel
> emulation platform (which is slowly being upgraded to virtio 1.0) without
> hanging during boot. Patch below.

Yikes, this is a nightmare.  That is exactly where I do not want things
to end up.  We really need to distinguish between legacy virtual crappy
virtio (and that includes v1) that totally ignores the bus it pretends
to be on, and sane virtio (to be defined) that sit on a real (or
properly emulated including iommu and details for dma mapping) bus.

Having a mumble jumble of arch specific undocumented magic as in
the powerpc patch replied to or this arm patch is a complete no-go.

Nacked-by: Christoph Hellwig <hch@lst.de>

for both.

  parent reply	other threads:[~2018-07-30  9:34 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-20  3:59 [RFC 0/4] Virtio uses DMA API for all devices Anshuman Khandual
2018-07-20  3:59 ` [RFC 1/4] virtio: Define virtio_direct_dma_ops structure Anshuman Khandual
2018-07-30  9:24   ` Christoph Hellwig
2018-07-31  4:01     ` Anshuman Khandual
2018-07-20  3:59 ` [RFC 2/4] virtio: Override device's DMA OPS with virtio_direct_dma_ops selectively Anshuman Khandual
2018-07-28  8:56   ` Anshuman Khandual
2018-07-28 21:16     ` Michael S. Tsirkin
2018-07-30  4:15       ` Anshuman Khandual
2018-07-30  9:30       ` Christoph Hellwig
2018-07-31  6:39         ` Anshuman Khandual
2018-07-30  9:25   ` Christoph Hellwig
2018-07-31  7:00     ` Anshuman Khandual
2018-07-20  3:59 ` [RFC 3/4] virtio: Force virtio core to use DMA API callbacks for all virtio devices Anshuman Khandual
2018-07-20  3:59 ` [RFC 4/4] virtio: Add platform specific DMA API translation for virito devices Anshuman Khandual
2018-07-20 13:15   ` Michael S. Tsirkin
2018-07-23  2:16     ` Anshuman Khandual
2018-07-25  4:30       ` Anshuman Khandual
2018-07-25 13:31       ` Michael S. Tsirkin
2018-07-20 13:16 ` [RFC 0/4] Virtio uses DMA API for all devices Michael S. Tsirkin
2018-07-23  6:28   ` Anshuman Khandual
2018-07-23  9:08     ` Michael S. Tsirkin
2018-07-25  3:26       ` Anshuman Khandual
2018-07-27 11:31         ` Michael S. Tsirkin
2018-07-28  8:37           ` Anshuman Khandual
2018-07-27  9:58 ` Will Deacon
2018-07-27 10:58   ` Anshuman Khandual
2018-07-30  9:34   ` Christoph Hellwig [this message]
2018-07-30 10:28     ` Michael S. Tsirkin
2018-07-30 11:18       ` Christoph Hellwig
2018-07-30 13:26         ` Michael S. Tsirkin
2018-07-31 17:30           ` Christoph Hellwig
2018-07-31 20:36             ` Benjamin Herrenschmidt
2018-08-01  8:16               ` Will Deacon
2018-08-01  8:36                 ` Christoph Hellwig
2018-08-01  9:05                   ` Will Deacon
2018-08-01 22:41                     ` Michael S. Tsirkin
2018-08-01 22:35                   ` Michael S. Tsirkin
2018-08-02 15:24                   ` Benjamin Herrenschmidt
2018-08-02 15:41                     ` Michael S. Tsirkin
2018-08-02 16:01                       ` Benjamin Herrenschmidt
2018-08-02 17:19                         ` Michael S. Tsirkin
2018-08-02 17:53                           ` Benjamin Herrenschmidt
2018-08-02 20:52                             ` Michael S. Tsirkin
2018-08-02 21:13                               ` Benjamin Herrenschmidt
2018-08-02 21:51                                 ` Michael S. Tsirkin
2018-08-03  7:05                                 ` Christoph Hellwig
2018-08-03 15:58                                   ` Benjamin Herrenschmidt
2018-08-03 16:02                                     ` Christoph Hellwig
2018-08-03 18:58                                       ` Benjamin Herrenschmidt
2018-08-04  8:21                                         ` Christoph Hellwig
2018-08-05  1:10                                           ` Benjamin Herrenschmidt
2018-08-05  7:29                                             ` Christoph Hellwig
2018-08-05 21:16                                               ` Benjamin Herrenschmidt
2018-08-05 21:30                                                 ` Benjamin Herrenschmidt
2018-08-06  9:42                                                 ` Christoph Hellwig
2018-08-06 19:52                                                   ` Benjamin Herrenschmidt
2018-08-07  6:21                                                     ` Christoph Hellwig
2018-08-07  6:42                                                       ` Benjamin Herrenschmidt
2018-08-07 13:55                                                         ` Christoph Hellwig
2018-08-07 20:32                                                           ` Benjamin Herrenschmidt
2018-08-08  6:31                                                             ` Christoph Hellwig
2018-08-08 10:07                                                               ` Benjamin Herrenschmidt
2018-08-08 12:30                                                                 ` Christoph Hellwig
2018-08-08 13:18                                                                   ` Benjamin Herrenschmidt
2018-08-08 20:31                                                                     ` Michael S. Tsirkin
2018-08-08 22:13                                                                       ` Benjamin Herrenschmidt
2018-08-09  2:00                                                                         ` Benjamin Herrenschmidt
2018-08-09  5:40                                                                         ` Christoph Hellwig
2018-09-07  0:09                                                                           ` Jiandi An
2018-09-10  6:19                                                                             ` Christoph Hellwig
2018-09-10  8:53                                                                               ` Gerd Hoffmann
2018-08-03 19:07                                     ` Michael S. Tsirkin
2018-08-04  1:11                                       ` Benjamin Herrenschmidt
2018-08-04  1:16                                       ` Benjamin Herrenschmidt
2018-08-05  0:22                                         ` Michael S. Tsirkin
2018-08-05  4:52                                           ` Benjamin Herrenschmidt
2018-08-06 13:46                                             ` Michael S. Tsirkin
2018-08-06 19:56                                               ` Benjamin Herrenschmidt
2018-08-06 20:35                                                 ` Michael S. Tsirkin
2018-08-06 21:26                                                   ` Benjamin Herrenschmidt
2018-08-06 21:46                                                     ` Michael S. Tsirkin
2018-08-06 22:13                                                       ` Benjamin Herrenschmidt
2018-08-06 23:16                                                         ` Benjamin Herrenschmidt
2018-08-06 23:45                                                         ` Michael S. Tsirkin
2018-08-07  0:18                                                           ` Benjamin Herrenschmidt
2018-08-07  6:32                                                           ` Christoph Hellwig
2018-08-07  6:27                                                         ` Christoph Hellwig
2018-08-07  6:44                                                           ` Benjamin Herrenschmidt
2018-08-07  6:18                                                       ` Christoph Hellwig
2018-08-07  6:16                                                     ` Christoph Hellwig
2018-08-06 23:18                                                   ` Benjamin Herrenschmidt
2018-08-07  6:12                                                   ` Christoph Hellwig
2018-08-04  1:18                                       ` Benjamin Herrenschmidt
2018-08-04  1:22                                       ` Benjamin Herrenschmidt
2018-08-05  0:23                                         ` Michael S. Tsirkin
2018-08-03 19:17                                   ` Michael S. Tsirkin
2018-08-04  8:15                                     ` Christoph Hellwig
2018-08-05  0:09                                       ` Michael S. Tsirkin
2018-08-05  1:11                                         ` Benjamin Herrenschmidt
2018-08-05  7:25                                         ` Christoph Hellwig
2018-08-05  0:53                                       ` Benjamin Herrenschmidt
2018-08-05  0:27                 ` Michael S. Tsirkin
2018-08-06 14:05                   ` Will Deacon
2018-08-01 21:56               ` Michael S. Tsirkin
2018-08-02 15:33                 ` Benjamin Herrenschmidt
2018-08-02 20:53                   ` Michael S. Tsirkin
2018-08-03  7:06                     ` Christoph Hellwig
2018-08-02 20:55 ` Michael S. Tsirkin
2018-08-03  2:41   ` Jason Wang
2018-08-03 19:08     ` Michael S. Tsirkin
2018-08-04  1:21       ` Benjamin Herrenschmidt
2018-08-05  0:24         ` Michael S. Tsirkin
2018-08-06  9:02           ` Anshuman Khandual
2018-08-06 13:36             ` Michael S. Tsirkin
2018-08-06 15:24               ` Christoph Hellwig
2018-08-06 16:06                 ` Michael S. Tsirkin
2018-08-06 16:10                   ` Christoph Hellwig
2018-08-06 16:13                     ` Michael S. Tsirkin
2018-08-06 16:34                       ` Christoph Hellwig

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