From: Liu Yi L
I/O Address Space IDs (IOASIDs) is used to tag DMA requests to target
multiple DMA address spaces for physical devices. Its PCI terminology
is called PASID (Process Address Space ID). Platforms with PASID support
can provide PASID granularity DMA isolation, which is very useful for
An IOASID can have multiple users, such as IOMMU driver, KVM, and device
drivers. The atomic IOASID notifier is used to inform users of IOASID
state change. For example, the IOASID_NOTIFY_UNBIND event is issued when
the IOASID is no longer bound to an address space. This requires ordered
actions
IOASID is used to identify address spaces that can be targeted by device
DMA. It is a system-wide resource that is essential to its many users.
This document is an attempt to help developers from all vendors navigate
the APIs. At this time, ARM SMMU and Intel’s Scalable IO Virtualization
(SIOV) ena
Bind guest page table call comes with an IOASID provided by the
userspace. To prevent attacks by malicious users, we must ensure the
IOASID was allocated under the same process.
This patch adds a new API that will perform an ownership check that is
based on whether the IOASID belongs to the ioasi
IOASIDs are used to associate DMA requests with virtual address spaces.
They are a system-wide limited resource made available to the userspace
applications. Let it be VMs or user-space device drivers.
This RFC patch introduces a cgroup controller to address the following
problems:
1. Some user ap
ioasid_set was introduced as an arbitrary token that is shared by a
group of IOASIDs. For example, two IOASIDs allocated via the same
ioasid_set pointer belong to the same set.
For guest SVA usages, system-wide IOASID resources need to be
partitioned such that each VM can have its own quota and be
Relations among IOASID users largely follow a publisher-subscriber
pattern. E.g. to support guest SVA on Intel Scalable I/O Virtualization
(SIOV) enabled platforms, VFIO, IOMMU, device drivers, KVM are all users
of IOASIDs. When a state change occurs, VFIO publishes the change event
that needs to b
IOASID private data can be cleared by ioasid_attach_data() with a NULL
data pointer. A common use case is for a caller to free the data
afterward. ioasid_attach_data() calls synchronize_rcu() before return
such that free data can be sure without outstanding readers.
However, since synchronize_rcu()
On Intel Scalable I/O Virtualization (SIOV) enabled platforms, IOMMU
driver is one of the users of IOASIDs. In normal flow, callers will
perform IOASID allocation, bind, unbind, and free in order. However, for
guest SVA, IOASID free could come before unbind as guest is untrusted.
This patch registe
Once IOASIDs cgroup is active, we must consult the limitation set up
by the cgroups during allocation. Freeing IOASIDs also need to return
the quota back to the cgroup.
Signed-off-by: Jacob Pan
---
drivers/iommu/ioasid.c | 7 ++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/d
As a system-wide resource, IOASID is often shared by multiple kernel
subsystems that are independent of each other. However, at the
ioasid_set level, these kernel subsystems must communicate with each
other for ownership checking, event notifications, etc. For example, on
Intel Scalable IO Virtuali
Signed-off-by: Jacob Pan
---
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-guid
IOASID is a system-wide resource that could vary on different systems.
The default capacity is 20 bits as defined in the PCI-E specifications.
This patch adds a function to allow adjusting system IOASID capacity.
For VT-d this is set during boot as part of the Intel IOMMU
initialization. APIs also
When an IOASID set is used for guest SVA, each VM will acquire its
ioasid_set for IOASID allocations. IOASIDs within the VM must have a
host/physical IOASID backing, mapping between guest and host IOASIDs can
be non-identical. IOASID set private ID (SPID) is introduced in this
patch to be used as g
Users of an ioasid_set may not keep track of all the IOASIDs allocated
under the set. When collective actions are needed for each IOASIDs, it
is useful to iterate over all the IOASIDs within the set. For example,
when the ioasid_set is freed, the user might perform the same cleanup
operation on eac
I/O Address Space ID (IOASID) core code was introduced in v5.5 as a generic
kernel allocator service for both PCIe Process Address Space ID (PASID) and
ARM SMMU's Substream ID. IOASIDs are used to associate DMA requests with
virtual address spaces, including both host and guest.
In addition to pro
Rename ioasid_set_data() to ioasid_attach_data() to avoid confusion with
struct ioasid_set. ioasid_set is a group of IOASIDs that share a common
token.
Reviewed-by: Jean-Philippe Brucker
Signed-off-by: Jacob Pan
---
drivers/iommu/intel/svm.c | 6 +++---
drivers/iommu/ioasid.c| 6 +++---
inc
Now that IOASID core keeps track of the IOASID to mm_struct ownership in
the forms of ioasid_set with IOASID_SET_TYPE_MM token type, there is no
need to keep the same mapping in VT-d driver specific data. Native SVM
usage is not affected by the change.
Signed-off-by: Jacob Pan
---
drivers/iommu/
When an actively used IOASID is freed due to exceptions, users must be
notified to perform the cleanup. The IOASID shall be put in a pending
state until all users completed their cleanup work.
This patch adds ioasid_free() function to let the caller initiate the
freeing process. Both ioasid_free()
On Mon, 22 Feb 2021, Maciej W. Rozycki wrote:
> > > I haven't booted Linux on my Malta for a while now, but it turns out to
> > > work just fine, and your patch set does not regress it booting multi-user
> > > NFS-rooted over FDDI.
> > >
> > > I note however that the system does not reboot pro
Hi Bjorn,
On 2021-02-27 00:44, Bjorn Andersson wrote:
> On Fri 26 Feb 12:23 CST 2021, Rob Clark wrote:
>
>
> The current logic picks one of:
> 1) is the compatible mentioned in qcom_smmu_impl_of_match[]
> 2) is the compatible an adreno
> 3) no quirks needed
>
> The change flips the order of the
25.02.2021 09:27, Nicolin Chen пишет:
...
>> The partially revert should be okay, but it's not clear to me what makes
>> difference for T124 since I don't see that problem on T30, which also
>> has active display at a boot time.
>
> Hmm..do you see ->attach_dev() is called from host1x_client_iommu
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