From: Jason Gunthorpe <jgg@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Nicolin Chen <nicolinc@nvidia.com>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
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Subject: Re: [PATCH v3 3/5] iommu: Add iommu_get_domain_for_dev_locked() helper
Date: Fri, 22 Aug 2025 10:21:38 -0300 [thread overview]
Message-ID: <20250822132138.GD1311579@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB5276A95E69D761271953E9F38C3DA@BN9PR11MB5276.namprd11.prod.outlook.com>
On Fri, Aug 22, 2025 at 09:45:28AM +0000, Tian, Kevin wrote:
> Thanks for the background. btw is it technically impossible or just
> not worth of the extra software complexity for no value?
Unsupported by HW. It cannot mix S2 and S1 formats on
SSIDs. If SSID is in use then all must be S1.
> e.g. if maintaining two page tables (S1/S2 formats) with exact same
> mappings, does SMMU allow smooth transition between two modes w/o
> breaking in-fly DMAs?
It could and there is SW support for that..
> but probably keeping two page tables in-sync in transition is
> already a problem w/o proper locking in map/unmap...
Yes, plus the doubling the memory. It is not worthwile there is really
very little advantange to the S2 format.
Jason
next prev parent reply other threads:[~2025-08-22 13:21 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-11 22:59 [PATCH v3 0/5] Disable ATS via iommu during PCI resets Nicolin Chen
2025-08-11 22:59 ` [PATCH v3 1/5] iommu: Lock group->mutex in iommu_deferred_attach Nicolin Chen
2025-08-15 5:09 ` Baolu Lu
2025-08-15 8:27 ` Tian, Kevin
2025-08-15 8:24 ` Tian, Kevin
2025-08-15 19:26 ` Nicolin Chen
2025-08-18 14:17 ` Jason Gunthorpe
2025-08-18 17:45 ` Nicolin Chen
2025-08-18 18:09 ` Jason Gunthorpe
2025-08-18 18:29 ` Nicolin Chen
2025-08-11 22:59 ` [PATCH v3 2/5] iommu: Pass in gdev to __iommu_device_set_domain Nicolin Chen
2025-08-15 5:18 ` Baolu Lu
2025-08-15 8:29 ` Tian, Kevin
2025-08-11 22:59 ` [PATCH v3 3/5] iommu: Add iommu_get_domain_for_dev_locked() helper Nicolin Chen
2025-08-15 5:28 ` Baolu Lu
2025-08-15 18:48 ` Nicolin Chen
2025-08-18 14:40 ` Jason Gunthorpe
2025-08-19 2:09 ` Baolu Lu
2025-08-15 8:55 ` Tian, Kevin
2025-08-15 18:45 ` Nicolin Chen
2025-08-21 8:07 ` Tian, Kevin
2025-08-21 14:41 ` Nicolin Chen
2025-08-31 23:24 ` Nicolin Chen
2025-08-18 14:39 ` Jason Gunthorpe
2025-08-18 17:22 ` Nicolin Chen
2025-08-18 23:42 ` Jason Gunthorpe
2025-08-19 5:09 ` Nicolin Chen
2025-08-19 12:52 ` Jason Gunthorpe
2025-08-19 17:22 ` Nicolin Chen
2025-08-21 13:13 ` Jason Gunthorpe
2025-08-21 15:22 ` Nicolin Chen
2025-08-21 18:37 ` Jason Gunthorpe
2025-08-22 5:11 ` Nicolin Chen
2025-08-21 8:11 ` Tian, Kevin
2025-08-21 13:14 ` Jason Gunthorpe
2025-08-22 9:45 ` Tian, Kevin
2025-08-22 13:21 ` Jason Gunthorpe [this message]
2025-08-11 22:59 ` [PATCH v3 4/5] iommu: Introduce iommu_dev_reset_prepare() and iommu_dev_reset_done() Nicolin Chen
2025-08-15 5:49 ` Baolu Lu
2025-08-15 20:10 ` Nicolin Chen
2025-08-15 9:14 ` Tian, Kevin
2025-08-15 19:45 ` Nicolin Chen
2025-08-11 22:59 ` [PATCH v3 5/5] pci: Suspend iommu function prior to resetting a device Nicolin Chen
2025-08-19 14:12 ` Ethan Zhao
2025-08-19 21:59 ` Nicolin Chen
2025-08-20 3:18 ` Ethan Zhao
2025-08-22 6:14 ` Nicolin Chen
2025-08-21 13:07 ` Jason Gunthorpe
2025-08-22 6:35 ` Nicolin Chen
2025-08-22 14:08 ` Jason Gunthorpe
2025-08-22 18:50 ` Nicolin Chen
2025-08-28 12:51 ` Jason Gunthorpe
2025-08-28 15:08 ` Nicolin Chen
2025-08-28 18:46 ` Jason Gunthorpe
2025-08-28 19:35 ` Nicolin Chen
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