From: Logan Gunthorpe <logang@deltatee.com>
To: "Christian König" <christian.koenig@amd.com>,
"Bjorn Helgaas" <helgaas@kernel.org>,
"Alex Williamson" <alex.williamson@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-block@vger.kernel.org,
"Stephen Bates" <sbates@raithlin.com>,
"Christoph Hellwig" <hch@lst.de>, "Jens Axboe" <axboe@kernel.dk>,
"Keith Busch" <keith.busch@intel.com>,
"Sagi Grimberg" <sagi@grimberg.me>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Jason Gunthorpe" <jgg@mellanox.com>,
"Max Gurtovoy" <maxg@mellanox.com>,
"Dan Williams" <dan.j.williams@intel.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>
Subject: Re: [PATCH v4 04/14] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches
Date: Tue, 8 May 2018 10:27:56 -0600 [thread overview]
Message-ID: <0b4183ef-e720-204b-9e85-b9eaf7a4136a@deltatee.com> (raw)
In-Reply-To: <e58e8d27-42a5-ca69-3b68-c409a2922cd1@amd.com>
On 08/05/18 01:17 AM, Christian König wrote:
> AMD APUs mandatory need the ACS flag set for the GPU integrated in the
> CPU when IOMMU is enabled or otherwise you will break SVM.
Well, given that the current set only disables ACS bits on bridges
(previous versions were only on switches) this shouldn't be an issue for
integrated devices. We do not disable ACS flags globally.
> And what exactly is the problem here? I'm currently testing P2P with
> GPUs in different IOMMU domains and at least with AMD IOMMUs that works
> perfectly fine.
In addition to Stephen's comments, seeing we've established a general
need to avoid the root complex (until we have a whitelist at least) we
must have ACS disabled along the path between the devices. Otherwise,
all TLPs will go through the root complex and if there is no support it
will fail.
If the consensus is we want a command line option, then so be it. But
we'll have to deny pretty much all P2P transactions unless the user
correctly disables ACS along the path using the command line option and
this is really annoying for users of this functionality to understand
how to do that correctly.
Logan
next prev parent reply other threads:[~2018-05-08 16:28 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-23 23:30 [PATCH v4 00/14] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 01/14] PCI/P2PDMA: Support peer-to-peer memory Logan Gunthorpe
2018-05-07 23:00 ` Bjorn Helgaas
2018-05-07 23:09 ` Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 02/14] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 03/14] PCI/P2PDMA: Add PCI p2pmem dma mappings to adjust the bus offset Logan Gunthorpe
2018-05-07 23:02 ` Bjorn Helgaas
2018-04-23 23:30 ` [PATCH v4 04/14] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches Logan Gunthorpe
2018-04-24 3:33 ` Randy Dunlap
2018-05-07 23:13 ` Bjorn Helgaas
2018-05-08 7:17 ` Christian König
2018-05-08 14:25 ` Stephen Bates
2018-05-08 16:37 ` Christian König
2018-05-08 16:27 ` Logan Gunthorpe [this message]
2018-05-08 16:50 ` Christian König
2018-05-08 19:13 ` Logan Gunthorpe
2018-05-08 19:34 ` Alex Williamson
2018-05-08 19:45 ` Logan Gunthorpe
2018-05-08 20:13 ` Alex Williamson
2018-05-08 20:19 ` Logan Gunthorpe
2018-05-08 20:43 ` Alex Williamson
2018-05-08 20:49 ` Logan Gunthorpe
2018-05-08 21:26 ` Alex Williamson
2018-05-08 21:42 ` Stephen Bates
2018-05-08 22:03 ` Alex Williamson
2018-05-08 22:10 ` Logan Gunthorpe
2018-05-08 22:25 ` Stephen Bates
2018-05-08 23:11 ` Alex Williamson
2018-05-08 23:31 ` Logan Gunthorpe
2018-05-09 0:17 ` Alex Williamson
2018-05-08 22:32 ` Alex Williamson
2018-05-08 23:00 ` Dan Williams
2018-05-08 23:15 ` Logan Gunthorpe
2018-05-09 12:38 ` Stephen Bates
2018-05-08 22:21 ` Don Dutile
2018-05-09 12:44 ` Stephen Bates
2018-05-09 15:58 ` Don Dutile
2018-05-08 20:50 ` Jerome Glisse
2018-05-08 21:35 ` Stephen Bates
2018-05-09 13:12 ` Stephen Bates
2018-05-09 13:40 ` Christian König
2018-05-09 15:41 ` Stephen Bates
2018-05-09 16:07 ` Jerome Glisse
2018-05-09 16:30 ` Stephen Bates
2018-05-09 17:49 ` Jerome Glisse
2018-05-10 14:20 ` Stephen Bates
2018-05-10 14:29 ` Christian König
2018-05-10 14:59 ` Jerome Glisse
2018-05-10 18:44 ` Stephen Bates
2018-05-09 16:45 ` Logan Gunthorpe
2018-05-10 12:52 ` Christian König
2018-05-10 14:16 ` Stephen Bates
2018-05-10 14:41 ` Jerome Glisse
2018-05-10 18:41 ` Stephen Bates
2018-05-10 18:59 ` Logan Gunthorpe
2018-05-10 19:10 ` Alex Williamson
2018-05-10 19:24 ` Jerome Glisse
2018-05-10 16:32 ` Logan Gunthorpe
2018-05-10 17:11 ` Stephen Bates
2018-05-10 17:15 ` Logan Gunthorpe
2018-05-11 8:52 ` Christian König
2018-05-11 15:48 ` Logan Gunthorpe
2018-05-11 21:50 ` Stephen Bates
2018-05-11 22:24 ` Stephen Bates
2018-05-11 22:55 ` Logan Gunthorpe
2018-05-08 14:31 ` Dan Williams
2018-05-08 14:44 ` Stephen Bates
2018-05-08 21:04 ` Don Dutile
2018-05-08 21:27 ` Stephen Bates
2018-05-08 23:06 ` Don Dutile
2018-05-09 0:01 ` Alex Williamson
2018-05-09 12:35 ` Stephen Bates
2018-05-09 14:44 ` Alex Williamson
2018-05-09 15:52 ` Don Dutile
2018-05-09 15:47 ` Don Dutile
2018-05-09 15:53 ` Don Dutile
2018-04-23 23:30 ` [PATCH v4 05/14] docs-rst: Add a new directory for PCI documentation Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 06/14] PCI/P2PDMA: Add P2P DMA driver writer's documentation Logan Gunthorpe
2018-05-07 23:20 ` Bjorn Helgaas
2018-05-22 21:24 ` Randy Dunlap
2018-05-22 21:28 ` Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 07/14] block: Introduce PCI P2P flags for request and request queue Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 08/14] IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 09/14] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 10/14] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 11/14] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 12/14] nvmet: Introduce helper functions to allocate and free request SGLs Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 13/14] nvmet-rdma: Use new SGL alloc/free helper for requests Logan Gunthorpe
2018-04-23 23:30 ` [PATCH v4 14/14] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
2018-05-02 11:51 ` [PATCH v4 00/14] Copy Offload in NVMe Fabrics with P2P PCI Memory Christian König
2018-05-02 15:56 ` Logan Gunthorpe
2018-05-03 9:05 ` Christian König
2018-05-03 15:59 ` Logan Gunthorpe
2018-05-03 17:29 ` Christian König
2018-05-03 18:43 ` Logan Gunthorpe
2018-05-04 14:27 ` Christian König
2018-05-04 15:52 ` Logan Gunthorpe
2018-05-07 23:23 ` Bjorn Helgaas
2018-05-07 23:34 ` Logan Gunthorpe
2018-05-08 16:57 ` Alex Williamson
2018-05-08 19:14 ` Logan Gunthorpe
2018-05-08 21:25 ` Don Dutile
2018-05-08 21:40 ` Alex Williamson
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