From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: LKML <linux-kernel@vger.kernel.org>,
Joerg Roedel <joro@8bytes.org>,
"Lu Baolu" <baolu.lu@linux.intel.com>,
David Woodhouse <dwmw2@infradead.org>,
iommu@lists.linux-foundation.org, cgroups@vger.kernel.org,
Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Eric Auger <eric.auger@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Jonathan Corbet <corbet@lwn.net>, Raj Ashok <ashok.raj@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
Wu Hao <hao.wu@intel.com>, Dave Jiang <dave.jiang@intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: [RFC PATCH 17/18] docs: cgroup-v1: Add IOASIDs controller
Date: Sat, 27 Feb 2021 14:01:25 -0800 [thread overview]
Message-ID: <1614463286-97618-18-git-send-email-jacob.jun.pan@linux.intel.com> (raw)
In-Reply-To: <1614463286-97618-1-git-send-email-jacob.jun.pan@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
Documentation/admin-guide/cgroup-v1/index.rst | 1 +
.../admin-guide/cgroup-v1/ioasids.rst | 110 ++++++++++++++++++
2 files changed, 111 insertions(+)
create mode 100644 Documentation/admin-guide/cgroup-v1/ioasids.rst
diff --git a/Documentation/admin-guide/cgroup-v1/index.rst b/Documentation/admin-guide/cgroup-v1/index.rst
index 226f64473e8e..f5e307dc4dbb 100644
--- a/Documentation/admin-guide/cgroup-v1/index.rst
+++ b/Documentation/admin-guide/cgroup-v1/index.rst
@@ -15,6 +15,7 @@ Control Groups version 1
devices
freezer-subsystem
hugetlb
+ ioasids
memcg_test
memory
net_cls
diff --git a/Documentation/admin-guide/cgroup-v1/ioasids.rst b/Documentation/admin-guide/cgroup-v1/ioasids.rst
new file mode 100644
index 000000000000..b30eb41bf1be
--- /dev/null
+++ b/Documentation/admin-guide/cgroup-v1/ioasids.rst
@@ -0,0 +1,110 @@
+========================================
+I/O Address Space ID (IOASID) Controller
+========================================
+
+Acronyms
+--------
+PASID:
+ Process Address Space ID, defined by PCIe
+SVA:
+ Shared Virtual Address
+
+Introduction
+------------
+
+IOASIDs are used to associate DMA requests with virtual address spaces. As
+a system-wide limited¹ resource, its constraints are managed by the IOASIDs
+cgroup subsystem. The specific use cases are:
+
+1. Some user applications exhaust all the available IOASIDs thus depriving
+ others of the same host.
+
+2. System admins need to provision VMs based on their needs for IOASIDs,
+ e.g. the number of VMs with assigned devices that perform DMA requests
+ with PASID.
+
+The IOASID subsystem consists of three components:
+
+- IOASID core: provides APIs for allocation, pool management,
+ notifications and refcounting. See Documentation/driver-api/ioasid.rst
+ for details
+- IOASID user: provides user allocation interface via /dev/ioasid
+- IOASID cgroup controller: manage resource distribution
+
+Resource Distribution Model
+---------------------------
+IOASID allocation is process-based in that IOASIDs are tied to page tables²,
+the threaded model is not supported. The allocation is rejected by the
+cgroup hierarchy once a limit is reached. However, organizational changes
+such as moving processes across cgroups are exempted. Therefore, it is
+possible to have ioasids.current > ioasids.max. It is not possible to do
+further allocation after the organizational change that exceeds the max.
+
+The system capacity of the IOASIDs is default to PCIe PASID size of 20 bits.
+IOASID core provides API to adjust the system capacity based on platforms.
+IOASIDs are used by both user applications (e.g. VMs and userspace drivers)
+and kernel (e.g. supervisor SVA). However, only user allocation is subject
+to cgroup constraints. Host kernel allocates a pool of IOASIDs where its
+quota is subtracted from the system capacity. IOASIDs cgroup consults with
+the IOASID core for available capacity when a new cgroup limit is granted.
+Upon creation, no IOASID allocation is allowed by the user processes within
+the new cgroup.
+
+Usage
+-----
+CGroup filesystem has the following IOASIDs controller specific entries:
+::
+
+ ioasids.current
+ ioasids.events
+ ioasids.max
+
+To use the IOASIDs controller, set ioasids.max to the limit of the number
+of IOASIDs that can be allocated. The file ioasids.current shows the current
+number of IOASIDs allocated within the cgroup.
+
+Example
+--------
+1. Mount the cgroup2 FS ::
+
+ $ mount -t cgroup2 none /mnt/cg2/
+
+2. Add ioasids controller ::
+
+ $ echo '+ioasids' > /mnt/cg2/cgroup.subtree_control
+
+3. Create a hierarchy, set non-zero limit (default 0) ::
+
+ $ mkdir /mnt/cg2/test1
+ $ echo 5 > /mnt/cg2/test1/ioasids.max
+
+4. Allocate IOASIDs within limit should succeed ::
+
+ $echo $$ > /mnt/cg2/test1/cgroup.procs
+ Do IOASID allocation via /dev/ioasid
+ ioasids.current:1
+ ioasids.max:5
+
+5. Attempt to allocate IOASIDs beyond limit should fail ::
+
+ ioasids.current:5
+ ioasids.max:5
+
+6. Attach a new process with IOASID already allocated to a cgroup could
+result in ioasids.current > ioasids.max, e.g. process with PID 1234 under
+a cgroup with IOASIDs controller has one IOASID allocated, moving it to
+test1 cgroup ::
+
+ $echo 1234 > /mnt/cg2/test1/cgroup.procs
+ ioasids.current:6
+ ioasids.max:5
+
+Notes
+-----
+¹ When IOASID is used for PCI Express PASID, the range is limited to the
+PASID size of 20 bits. For a device that its resources can be shared across
+the platform, the IOASID namespace must be system-wide in order to uniquely
+identify DMA request with PASID inside the device.
+
+² The primary use case is SVA, where CPU page tables are shared with DMA via
+IOMMU.
--
2.25.1
next prev parent reply other threads:[~2021-02-28 6:44 UTC|newest]
Thread overview: 269+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-27 22:01 [PATCH V4 00/18] IOASID extensions for guest SVA Jacob Pan
2021-02-27 22:01 ` [PATCH V4 01/18] docs: Document IO Address Space ID (IOASID) APIs Jacob Pan
2021-02-27 22:01 ` [PATCH V4 02/18] iommu/ioasid: Rename ioasid_set_data() Jacob Pan
2021-02-27 22:01 ` [PATCH V4 03/18] iommu/ioasid: Add a separate function for detach data Jacob Pan
2021-02-27 22:01 ` [PATCH V4 04/18] iommu/ioasid: Support setting system-wide capacity Jacob Pan
2021-02-27 22:01 ` [PATCH V4 05/18] iommu/ioasid: Redefine IOASID set and allocation APIs Jacob Pan
2021-03-19 0:22 ` Jacob Pan
2021-03-19 9:58 ` Jean-Philippe Brucker
2021-03-19 12:46 ` Jason Gunthorpe
2021-03-19 13:41 ` Jean-Philippe Brucker
2021-03-19 13:54 ` Jason Gunthorpe
2021-03-19 18:22 ` Jacob Pan
2021-03-22 9:24 ` Jean-Philippe Brucker
2021-03-24 17:02 ` Jacob Pan
2021-03-24 17:03 ` Jason Gunthorpe
2021-03-24 22:12 ` Jacob Pan
2021-03-25 10:21 ` Jean-Philippe Brucker
2021-03-25 17:02 ` Jacob Pan
2021-03-25 17:16 ` Jason Gunthorpe
2021-03-25 18:23 ` Jacob Pan
2021-03-26 8:06 ` Jean-Philippe Brucker
2021-03-30 13:07 ` Jason Gunthorpe
2021-03-30 13:42 ` Jean-Philippe Brucker
2021-03-30 13:46 ` Jason Gunthorpe
2021-03-25 10:26 ` Jean-Philippe Brucker
2021-03-22 12:03 ` Jason Gunthorpe
2021-03-24 19:05 ` Jacob Pan
2021-03-29 16:31 ` Jason Gunthorpe
2021-03-29 22:55 ` Jacob Pan
2021-03-30 13:43 ` Jason Gunthorpe
2021-03-31 0:10 ` Jacob Pan
2021-03-31 12:28 ` Jason Gunthorpe
2021-03-31 16:34 ` Jacob Pan
2021-03-31 17:31 ` Jason Gunthorpe
2021-03-31 18:20 ` Jacob Pan
2021-03-31 18:33 ` Jason Gunthorpe
2021-03-31 21:50 ` Jacob Pan
2021-03-31 8:38 ` Liu, Yi L
2021-03-30 1:37 ` Tian, Kevin
2021-03-30 13:28 ` Jason Gunthorpe
2021-03-31 7:38 ` Liu, Yi L
2021-03-31 12:40 ` Jason Gunthorpe
2021-04-01 4:38 ` Liu, Yi L
2021-04-01 7:04 ` Liu, Yi L
2021-04-01 11:54 ` Jason Gunthorpe
2021-04-02 12:46 ` Liu, Yi L
2021-04-01 12:05 ` Jean-Philippe Brucker
2021-04-01 12:12 ` Jason Gunthorpe
2021-04-01 13:38 ` Liu, Yi L
2021-04-01 13:42 ` Jason Gunthorpe
2021-04-01 14:08 ` Liu, Yi L
2021-04-01 16:03 ` Jason Gunthorpe
2021-04-02 7:30 ` Tian, Kevin
2021-04-05 23:35 ` Jason Gunthorpe
2021-04-06 0:37 ` Tian, Kevin
2021-04-06 12:15 ` Jason Gunthorpe
2021-04-15 13:11 ` Auger Eric
2021-04-15 23:07 ` Jason Gunthorpe
2021-04-16 13:12 ` Jacob Pan
2021-04-16 15:45 ` Alex Williamson
2021-04-16 17:23 ` Jacob Pan
2021-04-16 17:54 ` Jason Gunthorpe
2021-04-21 13:18 ` Liu, Yi L
2021-04-21 16:23 ` Jason Gunthorpe
2021-04-21 16:54 ` Alex Williamson
2021-04-21 17:52 ` Jason Gunthorpe
2021-04-21 19:33 ` Alex Williamson
2021-04-21 23:03 ` Jason Gunthorpe
2021-04-22 8:34 ` Tian, Kevin
2021-04-22 12:10 ` Jason Gunthorpe
2021-04-23 9:06 ` Tian, Kevin
2021-04-23 11:49 ` Jason Gunthorpe
2021-04-25 9:24 ` Tian, Kevin
2021-04-26 12:38 ` Jason Gunthorpe
2021-04-28 6:34 ` Tian, Kevin
2021-04-28 15:06 ` Alex Williamson
2021-05-07 7:36 ` Tian, Kevin
2021-05-07 11:56 ` Jason Gunthorpe
2021-05-07 17:06 ` Alex Williamson
2021-05-07 17:10 ` Jason Gunthorpe
2021-05-08 6:08 ` Tian, Kevin
2021-05-08 7:31 ` Tian, Kevin
2021-05-10 2:56 ` Lu Baolu
2021-04-28 20:46 ` Jason Gunthorpe
2021-05-04 16:22 ` Jacob Pan
2021-05-04 16:31 ` Jason Gunthorpe
2021-05-08 5:46 ` Tian, Kevin
2021-05-04 15:41 ` Jacob Pan
2021-05-04 18:00 ` Jason Gunthorpe
2021-05-04 22:11 ` Jacob Pan
2021-05-04 23:15 ` Jason Gunthorpe
2021-05-05 17:22 ` Jacob Pan
2021-05-05 18:00 ` Jason Gunthorpe
2021-05-05 20:04 ` Jacob Pan
2021-05-05 22:21 ` Jason Gunthorpe
2021-05-05 23:23 ` Raj, Ashok
2021-05-06 12:22 ` Jason Gunthorpe
2021-05-08 7:06 ` Liu Yi L
2021-05-06 7:23 ` Jean-Philippe Brucker
2021-05-06 12:27 ` Jason Gunthorpe
2021-05-06 16:32 ` Raj, Ashok
2021-05-07 17:20 ` Jason Gunthorpe
2021-05-07 18:14 ` Raj, Ashok
2021-05-07 18:20 ` Jason Gunthorpe
2021-05-07 19:23 ` Raj, Ashok
2021-05-07 19:28 ` Jason Gunthorpe
2021-05-07 22:15 ` Jacob Pan
2021-05-08 9:56 ` Tian, Kevin
2021-05-10 12:37 ` Jason Gunthorpe
2021-05-10 15:25 ` Raj, Ashok
2021-05-10 15:31 ` Jason Gunthorpe
2021-05-10 16:22 ` Raj, Ashok
2021-05-10 16:39 ` Jason Gunthorpe
2021-05-10 22:28 ` Jacob Pan
2021-05-10 23:45 ` Jason Gunthorpe
2021-05-11 3:56 ` Jacob Pan
2021-05-11 9:10 ` Tian, Kevin
2021-05-11 13:24 ` Liu Yi L
2021-05-11 22:52 ` Tian, Kevin
2021-05-11 14:38 ` Jason Gunthorpe
2021-05-11 22:51 ` Tian, Kevin
2021-05-11 23:39 ` Jason Gunthorpe
2021-05-12 0:21 ` Tian, Kevin
2021-05-12 0:25 ` Jason Gunthorpe
2021-05-12 0:40 ` Tian, Kevin
2021-04-29 8:54 ` Auger Eric
2021-04-29 8:55 ` Auger Eric
2021-04-29 13:26 ` Auger Eric
2021-04-29 20:04 ` Jason Gunthorpe
2021-05-05 9:10 ` Auger Eric
2021-04-22 17:13 ` Alex Williamson
2021-04-22 17:57 ` Jason Gunthorpe
2021-04-22 19:37 ` Alex Williamson
2021-04-22 20:00 ` Jason Gunthorpe
2021-04-22 22:38 ` Alex Williamson
2021-04-22 23:39 ` Jason Gunthorpe
2021-04-23 10:31 ` Tian, Kevin
2021-04-23 11:57 ` Jason Gunthorpe
2021-04-27 5:11 ` David Gibson
2021-04-27 16:39 ` Jason Gunthorpe
2021-04-28 0:49 ` David Gibson
2021-04-23 16:38 ` Alex Williamson
2021-04-23 22:28 ` Jason Gunthorpe
2021-04-27 5:15 ` David Gibson
2021-04-27 5:08 ` David Gibson
2021-04-27 17:12 ` Jason Gunthorpe
2021-04-28 0:58 ` David Gibson
2021-04-28 14:56 ` Jason Gunthorpe
2021-04-29 3:04 ` David Gibson
2021-05-03 16:15 ` Jason Gunthorpe
2021-05-13 5:48 ` David Gibson
2021-05-13 13:59 ` Jason Gunthorpe
2021-05-24 7:52 ` David Gibson
2021-05-24 23:37 ` Jason Gunthorpe
2021-05-25 19:26 ` Kirti Wankhede
2021-05-25 19:52 ` Jason Gunthorpe
2021-05-25 21:18 ` Kirti Wankhede
2021-05-27 5:00 ` David Gibson
2021-05-27 18:25 ` Kirti Wankhede
2021-06-01 3:45 ` David Gibson
2021-05-27 4:58 ` David Gibson
2021-05-27 18:48 ` Jason Gunthorpe
2021-06-01 4:03 ` David Gibson
2021-06-01 12:57 ` Jason Gunthorpe
2021-06-08 0:44 ` David Gibson
2021-06-08 18:34 ` Jason Gunthorpe
2021-05-25 22:52 ` Alex Williamson
2021-05-26 18:10 ` Kirti Wankhede
2021-05-26 18:59 ` Alex Williamson
2021-05-26 19:13 ` Jason Gunthorpe
2021-05-27 4:53 ` David Gibson
2021-05-27 19:06 ` Jason Gunthorpe
2021-06-01 4:27 ` David Gibson
2021-04-28 6:58 ` Tian, Kevin
2021-05-04 17:12 ` Jason Gunthorpe
2021-05-07 8:09 ` Tian, Kevin
2021-04-28 7:47 ` Tian, Kevin
2021-04-28 18:41 ` Jason Gunthorpe
2021-04-27 4:50 ` David Gibson
2021-04-27 17:24 ` Jason Gunthorpe
2021-04-28 1:23 ` David Gibson
2021-04-29 0:21 ` Jason Gunthorpe
2021-04-29 3:20 ` David Gibson
2021-05-03 16:05 ` Jason Gunthorpe
2021-05-04 3:54 ` David Gibson
2021-05-04 18:15 ` Jason Gunthorpe
2021-05-05 4:28 ` Alexey Kardashevskiy
2021-05-05 16:39 ` Jason Gunthorpe
2021-05-13 6:07 ` David Gibson
2021-05-13 13:50 ` Jason Gunthorpe
2021-05-24 7:56 ` David Gibson
2021-05-13 6:01 ` David Gibson
2021-05-13 6:52 ` Tian, Kevin
2021-05-13 13:47 ` Jason Gunthorpe
2021-04-22 12:55 ` Liu Yi L
2021-04-16 13:38 ` Auger Eric
2021-04-16 14:05 ` Jason Gunthorpe
2021-04-16 14:26 ` Auger Eric
2021-04-16 14:34 ` Jason Gunthorpe
2021-04-16 15:00 ` Auger Eric
2021-04-01 11:46 ` Jason Gunthorpe
2021-04-01 13:10 ` Liu, Yi L
2021-04-01 13:15 ` Jason Gunthorpe
2021-04-01 13:43 ` Liu, Yi L
2021-04-01 13:46 ` Jason Gunthorpe
2021-04-02 7:58 ` Tian, Kevin
2021-04-05 23:39 ` Jason Gunthorpe
2021-04-06 1:02 ` Tian, Kevin
2021-04-06 12:21 ` Jason Gunthorpe
2021-04-07 2:23 ` Tian, Kevin
[not found] ` <MWHPR11MB188628BDB37A4EE36F3D99338C769@MWHPR11MB1886.namprd11.prod.outlook.com>
2021-04-06 2:08 ` Tian, Kevin
2021-04-02 10:01 ` Tian, Kevin
2021-04-02 8:22 ` Tian, Kevin
2021-04-05 23:42 ` Jason Gunthorpe
2021-04-06 1:27 ` Tian, Kevin
2021-04-06 12:34 ` Jason Gunthorpe
2021-04-07 2:08 ` Tian, Kevin
2021-04-07 12:20 ` Jason Gunthorpe
2021-04-07 23:50 ` Tian, Kevin
2021-04-08 11:41 ` Jason Gunthorpe
2021-04-06 1:35 ` Jason Wang
2021-04-06 12:42 ` Jason Gunthorpe
2021-04-07 2:06 ` Jason Wang
2021-04-07 8:17 ` Tian, Kevin
2021-04-07 11:58 ` Jason Gunthorpe
2021-04-07 18:43 ` Jean-Philippe Brucker
2021-04-07 19:36 ` Jason Gunthorpe
2021-04-08 9:37 ` Jean-Philippe Brucker
2021-03-30 2:24 ` Tian, Kevin
2021-03-30 13:24 ` Jason Gunthorpe
2021-03-30 4:14 ` Tian, Kevin
2021-03-30 13:27 ` Jason Gunthorpe
2021-03-31 7:41 ` Liu, Yi L
2021-03-31 12:38 ` Jason Gunthorpe
2021-03-31 23:46 ` Jacob Pan
2021-04-01 0:37 ` Jason Gunthorpe
2021-04-01 17:23 ` Jacob Pan
2021-04-01 17:26 ` Jason Gunthorpe
2021-03-19 17:14 ` Jacob Pan
2021-02-27 22:01 ` [PATCH V4 06/18] iommu/ioasid: Add free function and states Jacob Pan
2021-02-27 22:01 ` [PATCH V4 07/18] iommu/ioasid: Add ioasid_set iterator helper functions Jacob Pan
2021-02-27 22:01 ` [PATCH V4 08/18] iommu/ioasid: Introduce ioasid_set private ID Jacob Pan
2021-02-27 22:01 ` [PATCH V4 09/18] iommu/ioasid: Introduce notification APIs Jacob Pan
2021-02-27 22:01 ` [PATCH V4 10/18] iommu/ioasid: Support mm token type ioasid_set notifications Jacob Pan
2021-02-27 22:01 ` [PATCH V4 11/18] iommu/ioasid: Add ownership check in guest bind Jacob Pan
2021-02-27 22:01 ` [PATCH V4 12/18] iommu/vt-d: Remove mm reference for guest SVA Jacob Pan
2021-02-27 22:01 ` [PATCH V4 13/18] iommu/ioasid: Add a workqueue for cleanup work Jacob Pan
2021-02-27 22:01 ` [PATCH V4 14/18] iommu/vt-d: Listen to IOASID notifications Jacob Pan
2021-02-27 22:01 ` [RFC PATCH 15/18] cgroup: Introduce ioasids controller Jacob Pan
2021-03-03 15:44 ` Tejun Heo
2021-03-03 21:17 ` Jacob Pan
2021-03-04 0:02 ` Jacob Pan
2021-03-04 0:23 ` Jason Gunthorpe
2021-03-04 9:49 ` Jean-Philippe Brucker
2021-03-04 17:46 ` Jacob Pan
2021-03-04 17:54 ` Jason Gunthorpe
2021-03-04 19:01 ` Jacob Pan
2021-03-04 19:02 ` Jason Gunthorpe
2021-03-04 21:28 ` Jacob Pan
2021-03-05 8:30 ` Jean-Philippe Brucker
2021-03-05 17:16 ` Jean-Philippe Brucker
2021-03-05 18:20 ` Jacob Pan
2021-02-27 22:01 ` [RFC PATCH 16/18] iommu/ioasid: Consult IOASIDs cgroup for allocation Jacob Pan
2021-02-27 22:01 ` Jacob Pan [this message]
2021-02-27 22:01 ` [RFC PATCH 18/18] ioasid: Add /dev/ioasid for userspace Jacob Pan
2021-03-10 19:23 ` Jason Gunthorpe
2021-03-11 22:55 ` Jacob Pan
2021-03-12 14:54 ` Jason Gunthorpe
2021-03-02 12:58 ` [PATCH V4 00/18] IOASID extensions for guest SVA Liu, Yi L
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