From: Jason Gunthorpe via iommu <iommu@lists.linux-foundation.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH RFC v2 03/11] iommu/sva: Add iommu_domain type for SVA
Date: Wed, 6 Apr 2022 10:06:14 -0300 [thread overview]
Message-ID: <20220406130614.GC2120790@nvidia.com> (raw)
In-Reply-To: <d0f6caea-0cd9-d839-c9fb-0fe49c2bad16@arm.com>
On Wed, Apr 06, 2022 at 01:32:07PM +0100, Robin Murphy wrote:
> a particular IOMMU instance, and potentially allocate separate domains for
> separate devices to represent the same address space, much like
> vfio_iommu_type1_attach_group() does.
I think this VFIO code also needs some more work, it currently assumes
that if the domain ops are the same then the domains are compatible,
and that is not true for ARM SMMU drivers.
I've been thinking of adding a domain callback 'can device attach' and
replacing the ops compare with that instead.
> It's not really worth IOMMU drivers trying to support a domain spanning
> potentially-heterogeneous instances internally, since they can't reasonably
> know what matters in any particular situation.
In the long run I think it will be worth optimizing. If the SMMU
instances can share IOPTE memory then we get two wins - memory
reduction and reduced work to read dirty bits.
The dirty read in particular is very performance sensitive so if real
work loads have many SMMUs per VM it will become a pain point.
Jason
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next prev parent reply other threads:[~2022-04-06 13:06 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-29 5:37 [PATCH RFC v2 00/11] iommu: SVA and IOPF refactoring Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 01/11] iommu: Add pasid_bits field in struct dev_iommu Lu Baolu
2022-03-29 21:00 ` Jacob Pan
2022-03-30 4:30 ` Lu Baolu
2022-03-30 7:05 ` Tian, Kevin
2022-03-30 11:58 ` Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 02/11] iommu: Add iommu_group_singleton_lockdown() Lu Baolu
2022-03-29 8:42 ` Tian, Kevin
2022-03-29 11:42 ` Jason Gunthorpe via iommu
2022-03-30 6:50 ` Tian, Kevin
2022-03-30 11:57 ` Lu Baolu
2022-03-30 11:58 ` Jason Gunthorpe via iommu
2022-03-30 14:12 ` Tian, Kevin
2022-03-30 14:30 ` Jason Gunthorpe via iommu
2022-04-02 7:12 ` Tian, Kevin
2022-04-02 23:29 ` Jason Gunthorpe via iommu
2022-04-06 10:02 ` Lu Baolu
2022-04-06 10:44 ` Tian, Kevin
2022-04-06 11:03 ` Lu Baolu
2022-04-06 23:56 ` Tian, Kevin
2022-03-30 14:18 ` Tian, Kevin
2022-03-30 15:04 ` Alex Williamson
2022-04-04 5:43 ` Lu Baolu
2022-04-04 17:24 ` Jason Gunthorpe via iommu
2022-04-05 6:12 ` Lu Baolu
2022-04-05 14:10 ` Jason Gunthorpe via iommu
2022-04-06 9:51 ` Lu Baolu
2022-04-01 6:20 ` Yi Liu
2022-04-01 11:52 ` Jason Gunthorpe via iommu
2022-03-30 4:59 ` Lu Baolu
2022-03-30 6:55 ` Tian, Kevin
2022-04-01 5:49 ` Yi Liu
2022-03-29 5:37 ` [PATCH RFC v2 03/11] iommu/sva: Add iommu_domain type for SVA Lu Baolu
2022-03-29 21:38 ` Jacob Pan
2022-03-30 4:35 ` Lu Baolu
2022-03-30 19:02 ` Jason Gunthorpe via iommu
2022-04-02 8:43 ` Tian, Kevin
2022-04-02 23:32 ` Jason Gunthorpe via iommu
2022-04-04 6:09 ` Lu Baolu
2022-04-06 1:00 ` Tian, Kevin
2022-04-06 1:23 ` Jason Gunthorpe via iommu
2022-04-06 5:58 ` Tian, Kevin
2022-04-06 12:32 ` Robin Murphy
2022-04-06 13:06 ` Jason Gunthorpe via iommu [this message]
2022-04-06 13:37 ` Robin Murphy
2022-04-06 14:01 ` Jason Gunthorpe via iommu
2022-04-07 0:11 ` Tian, Kevin
2022-03-29 5:37 ` [PATCH RFC v2 04/11] iommu: Add attach/detach_dev_pasid domain ops Lu Baolu
2022-03-30 19:08 ` Jason Gunthorpe via iommu
2022-04-04 6:47 ` Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 05/11] iommu/vt-d: Remove SVM_FLAG_SUPERVISOR_MODE suport Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 06/11] iommu/vt-d: Add SVA domain support Lu Baolu
2022-03-30 19:09 ` Jason Gunthorpe via iommu
2022-04-04 6:52 ` Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 07/11] arm-smmu-v3/sva: " Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 08/11] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces Lu Baolu
2022-03-31 20:59 ` Jacob Pan
2022-03-31 22:26 ` Jason Gunthorpe via iommu
2022-04-04 5:55 ` Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 09/11] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-03-29 5:37 ` [PATCH RFC v2 10/11] iommu: Per-domain I/O page fault handling Lu Baolu
2022-03-29 5:38 ` [PATCH RFC v2 11/11] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu
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