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From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@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 05/14] iommufd: Add IOMMUFD_OBJ_VIOMMU and IOMMUFD_CMD_VIOMMU_ALLOC
Date: Tue, 21 May 2024 15:05:55 -0300	[thread overview]
Message-ID: <20240521180555.GM20229@nvidia.com> (raw)
In-Reply-To: <ZkQNxkYv23z7i6e0@nvidia.com>

On Tue, May 14, 2024 at 06:20:06PM -0700, Nicolin Chen wrote:
> > I suspect 0 should be reserved as a non-set value for some
> > basic sanity in all these driver type enums.
> 
> We have an IOMMU_HWPT_DATA_NONE for HWPT_ALLOC to compatible
> with an S2 hwpt, since it doesn't need a data.
> 
> Maybe we can have an IOMMU_VIOMMU_TYPE_DEFAULT to be 0, for
> an IOMMU driver (e.g. VT-d) that doesn't need to handle nor
> be aware of any viommu object?

Seems like a good practice, and perhaps userspace will find value in a
generic viommu object that is always present.

> That makes a lot sense. I'd need to go through QEMU code and
> see how we will accommodate these two more naturally: likely
> the QEMU core should allocate an S2 HWPT for a VM, while the
> viommu code should allocate a VIOMMU for each instance.

I'd suggest that core qemu should allocate the S2 IOAS and pass that
to the qemu viommu driver

The qemu viommu driver should create the hwpt and then the viommu and
perhaps return the viommu or hwpt back to the core code.

If the vSTE flow above is used for identity then the qemu viommu
driver would also have to go an create vSTEs for identity and attach
them to all devices before the VM starts up. Then when the OS
activates the SMMU it would have to mirror the real vSTE from guest
memory to the kernel.

Not sure there is value in having the core qemu code directly access
the hwpt/viommu?

Jason

  reply	other threads:[~2024-05-21 18:06 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 [this message]
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
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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