From: Nicolin Chen <nicolinc@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: <will@kernel.org>, <robin.murphy@arm.com>, <kevin.tian@intel.com>,
<suravee.suthikulpanit@amd.com>, <joro@8bytes.org>,
<linux-kernel@vger.kernel.org>, <iommu@lists.linux.dev>,
<linux-arm-kernel@lists.infradead.org>,
<linux-tegra@vger.kernel.org>, <yi.l.liu@intel.com>,
<eric.auger@redhat.com>, <vasant.hegde@amd.com>,
<jon.grimm@amd.com>, <santosh.shukla@amd.com>,
<Dhaval.Giani@amd.com>, <shameerali.kolothum.thodi@huawei.com>
Subject: Re: [PATCH RFCv1 07/14] iommufd: Add viommu set/unset_dev_id ops
Date: Tue, 14 May 2024 18:59:07 -0700 [thread overview]
Message-ID: <ZkQW6/OAQ8MzN6Go@nvidia.com> (raw)
In-Reply-To: <ZkOI8ztR1mUMJ8oe@nvidia.com>
On Tue, May 14, 2024 at 12:53:23PM -0300, Jason Gunthorpe wrote:
> On Sun, May 12, 2024 at 09:39:15PM -0700, Nicolin Chen wrote:
> > On Sun, May 12, 2024 at 11:46:54AM -0300, Jason Gunthorpe wrote:
> > > On Fri, Apr 12, 2024 at 08:47:04PM -0700, Nicolin Chen wrote:
> > > > Add a pair of ops to set and unet device's virtual ID that belongs to
> > > > a viommu object. They will be used, in the following patch, by iommufd
> > > > to support some HW-acceleration feature from the host level.
> > > >
> > > > For instance, every device behind an ARM SMMU has a Stream ID. The ID
> > > > is used by ATC invalidation commands so SMMU HW can direct invalidation
> > > > requests to the corresponding PCI device where the ID belongs to. In a
> > > > virtualization use case, a passthroughed device in the VM will have a
> > > > virtuail Stream ID, used by the ATC invalidation commands in the guest
> > > > system. NVIDIA's CMDQV extension for SMMUv3 provides a v-interface to
> > > > execute the guest-level ATC invalidation commands directly, yet needs
> > > > the HW to be aware of its virtual Stream ID so it can replace with its
> > > > physical Stream ID.
> > >
> > > I imagine using this as well for the ATC invalidation commands. It
> > > would be very easy and simplifying if the command fixup just extracted
> > > the vSID from the ATC invalidation and used an xarray to turn it into
> > > a pSID and then pushed the resulting command.
> >
> > You mean the nested SMMU series right? Actually the set_dev_id
> > ioctl was a part of that until we wanted to try DEV_INVALIDATE.
>
> Yes, there is nothing inherently wrong with DEV_INVALIDATE, we could
> continue to use that as the API and automatically pick up the VIOMMU
> instance from the nesting domain to process the ATS.
>
> The VMM needs a reliable place to send the CMDQ data, on ARM/AMD this
> needs to be an always available global-to-the-viommu thing. Intel
> needs to associate the virtual invalidation with the correct nesting
> domain as well.
>
> So I original thought it would nice and simple to have a
> VIOMMU_INVALIDATE as well.
>
> But.. If we need a nesting domain that is indentity (ie the S2) then
> when the VIOMMU is created then we'd also create an identity nesting
> domain as well.
So, you want a proxy S1 domain for a device to attach, in case
of a stage-2 only setup, because an S2 domain will no longer has
a VMID, since it's shared among viommus. In the SMMU driver case,
an arm_smmu_domain won't have an smmu pointer, so a device can't
attach to an S2 domain but always an nested S1 domain, right?
> Functionally we could use that global nesting domain
> to deliver the DEV_INVALIDATE too.
If my narrative above is correct, the device is actually still
attached to S2 domain via a proxy nested S1 domain. What cache
do we need to invalidate except S2 mappings in this case?
> > So again, yes, it makes sense to me that we move viommu and the
> > set_dev_id to the nested series, and then drop DEV_INVALIDATE.
>
> I would like to do this bit by bit. viommu is a big series on its own.
>
> DEV_INVALIDATE is fine, it just can't do ATS invalidation.
I am not very sure about AMD. Intel doesn't need DEV_INVALIDATE
at this moment. SMMU only uses DEV_INVALIDATE for ATC and CD
invalidations, which can be both shifted to VIOMMU_INVALIDATE.
Same question: any other case can we use the DEV_INVALIDATE for?
> We can add ATS invalidation after either as an enhancement as part of
> adding the VIOMMU either as DEV_INVALIDATE or VIOMMU_INVALIDATE (or
> both)
Yea, maybe step by step like this:
Part-1 VIOMMU_ALLOC and VIOMMU_ATTACH
Part-2 VIOMMU_SET/UNSET_VDEV_ID
Part-3 VIOMMU_INVALIDATE
Part-4 VQUEUE_ALLOC
...
Thanks
Nicolin
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next prev parent reply other threads:[~2024-05-15 2:00 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-13 3:46 [PATCH RFCv1 00/14] Add Tegra241 (Grace) CMDQV Support (part 2/2) Nicolin Chen
2024-04-13 3:46 ` [PATCH RFCv1 01/14] iommufd: Move iommufd_object to public iommufd header Nicolin Chen
2024-05-12 13:21 ` Jason Gunthorpe
2024-05-12 22:40 ` Nicolin Chen
2024-05-13 22:30 ` Jason Gunthorpe
2024-04-13 3:46 ` [PATCH RFCv1 02/14] iommufd: Swap _iommufd_object_alloc and __iommufd_object_alloc Nicolin Chen
2024-05-12 13:26 ` Jason Gunthorpe
2024-05-13 2:29 ` Nicolin Chen
2024-05-13 3:44 ` Nicolin Chen
2024-05-13 22:30 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 03/14] iommufd: Prepare for viommu structures and functions Nicolin Chen
2024-05-12 13:42 ` Jason Gunthorpe
2024-05-13 2:35 ` Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 04/14] iommufd: Add struct iommufd_viommu and iommufd_viommu_ops Nicolin Chen
2024-05-12 14:03 ` Jason Gunthorpe
2024-05-13 3:34 ` Nicolin Chen
2024-05-14 15:55 ` Jason Gunthorpe
2024-05-22 8:58 ` Tian, Kevin
2024-05-22 9:57 ` Baolu Lu
2024-05-22 13:39 ` Jason Gunthorpe
2024-05-23 1:43 ` Tian, Kevin
2024-05-23 4:01 ` Nicolin Chen
2024-05-23 5:40 ` Tian, Kevin
2024-05-23 12:58 ` Jason Gunthorpe
2024-05-24 2:16 ` Tian, Kevin
2024-05-24 13:03 ` Jason Gunthorpe
2024-05-24 2:36 ` Tian, Kevin
2024-04-13 3:47 ` [PATCH RFCv1 05/14] iommufd: Add IOMMUFD_OBJ_VIOMMU and IOMMUFD_CMD_VIOMMU_ALLOC Nicolin Chen
2024-05-12 14:27 ` Jason Gunthorpe
2024-05-13 4:33 ` Nicolin Chen
2024-05-14 15:38 ` Jason Gunthorpe
2024-05-15 1:20 ` Nicolin Chen
2024-05-21 18:05 ` Jason Gunthorpe
2024-05-22 0:13 ` Nicolin Chen
2024-05-22 16:46 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 06/14] iommufd/selftest: Add IOMMU_VIOMMU_ALLOC test coverage Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 07/14] iommufd: Add viommu set/unset_dev_id ops Nicolin Chen
2024-05-12 14:46 ` Jason Gunthorpe
2024-05-13 4:39 ` Nicolin Chen
2024-05-14 15:53 ` Jason Gunthorpe
2024-05-15 1:59 ` Nicolin Chen [this message]
2024-05-21 18:24 ` Jason Gunthorpe
2024-05-21 22:27 ` Nicolin Chen
2024-05-22 13:59 ` Jason Gunthorpe
2024-05-23 6:19 ` Tian, Kevin
2024-05-23 15:01 ` Jason Gunthorpe
2024-05-24 2:21 ` Tian, Kevin
2024-05-24 3:26 ` Nicolin Chen
2024-05-24 5:24 ` Tian, Kevin
2024-05-24 5:57 ` Nicolin Chen
2024-05-24 7:21 ` Tian, Kevin
2024-05-24 13:12 ` Jason Gunthorpe
2024-05-24 13:05 ` Jason Gunthorpe
2024-05-23 5:44 ` Tian, Kevin
2024-05-23 6:09 ` Nicolin Chen
2024-05-23 6:22 ` Tian, Kevin
2024-05-23 13:33 ` Jason Gunthorpe
2024-05-12 14:51 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 08/14] iommufd: Add IOMMU_VIOMMU_SET_DEV_ID ioctl Nicolin Chen
2024-05-12 14:58 ` Jason Gunthorpe
2024-05-13 5:24 ` Nicolin Chen
2024-05-17 5:14 ` Nicolin Chen
2024-05-21 18:30 ` Jason Gunthorpe
2024-05-22 2:15 ` Nicolin Chen
2024-05-23 6:42 ` Tian, Kevin
2024-05-24 5:40 ` Nicolin Chen
2024-05-24 7:13 ` Tian, Kevin
2024-05-24 13:19 ` Jason Gunthorpe
2024-05-27 1:08 ` Tian, Kevin
2024-05-28 20:22 ` Nicolin Chen
2024-05-28 20:33 ` Nicolin Chen
2024-05-29 2:58 ` Tian, Kevin
2024-05-29 3:20 ` Nicolin Chen
2024-05-30 0:28 ` Tian, Kevin
2024-05-30 0:58 ` Nicolin Chen
2024-05-30 3:05 ` Tian, Kevin
2024-05-30 4:26 ` Nicolin Chen
2024-06-01 21:45 ` Jason Gunthorpe
2024-06-03 3:25 ` Nicolin Chen
2024-06-06 18:24 ` Jason Gunthorpe
2024-06-06 18:44 ` Nicolin Chen
2024-06-07 0:27 ` Jason Gunthorpe
2024-06-07 0:36 ` Tian, Kevin
2024-06-07 14:49 ` Jason Gunthorpe
2024-06-07 21:19 ` Nicolin Chen
2024-06-10 12:04 ` Jason Gunthorpe
2024-06-10 20:01 ` Nicolin Chen
2024-06-10 22:01 ` Jason Gunthorpe
2024-06-10 23:04 ` Nicolin Chen
2024-06-11 0:28 ` Jason Gunthorpe
2024-06-11 0:44 ` Nicolin Chen
2024-06-11 12:17 ` Jason Gunthorpe
2024-06-11 19:11 ` Nicolin Chen
2024-05-28 20:30 ` Nicolin Chen
2024-05-24 13:20 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 09/14] iommufd/selftest: Add IOMMU_VIOMMU_SET_DEV_ID test coverage Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 10/14] iommufd/selftest: Add IOMMU_TEST_OP_MV_CHECK_DEV_ID Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 11/14] iommufd: Add struct iommufd_vqueue and its related viommu ops Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 12/14] iommufd: Add IOMMUFD_OBJ_VQUEUE and IOMMUFD_CMD_VQUEUE_ALLOC Nicolin Chen
2024-05-12 15:02 ` Jason Gunthorpe
2024-05-13 4:41 ` Nicolin Chen
2024-05-13 22:36 ` Jason Gunthorpe
2024-05-23 6:57 ` Tian, Kevin
2024-05-24 4:42 ` Nicolin Chen
2024-05-24 5:26 ` Tian, Kevin
2024-05-24 6:03 ` Nicolin Chen
2024-05-23 7:05 ` Tian, Kevin
2024-04-13 3:47 ` [PATCH RFCv1 13/14] iommufd: Add mmap infrastructure Nicolin Chen
2024-05-12 15:19 ` Jason Gunthorpe
2024-05-13 4:43 ` Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 14/14] iommu/tegra241-cmdqv: Add user-space use support Nicolin Chen
2024-05-22 8:40 ` [PATCH RFCv1 00/14] Add Tegra241 (Grace) CMDQV Support (part 2/2) Tian, Kevin
2024-05-22 16:48 ` Jason Gunthorpe
2024-05-22 19:47 ` Nicolin Chen
2024-05-22 23:28 ` Jason Gunthorpe
2024-05-22 23:43 ` Tian, Kevin
2024-05-23 3:09 ` Nicolin Chen
2024-05-23 12:48 ` Jason Gunthorpe
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