From: Alex Williamson <alex.williamson@redhat.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
"Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Christoph Hellwig" <hch@infradead.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH RFC v2 02/11] iommu: Add iommu_group_singleton_lockdown()
Date: Wed, 30 Mar 2022 09:04:34 -0600 [thread overview]
Message-ID: <20220330090434.22224951.alex.williamson@redhat.com> (raw)
In-Reply-To: <BN9PR11MB52766A3E3BC82EEF437258198C1F9@BN9PR11MB5276.namprd11.prod.outlook.com>
On Wed, 30 Mar 2022 14:18:47 +0000
"Tian, Kevin" <kevin.tian@intel.com> wrote:
> +Alex
>
> > From: Tian, Kevin
> > Sent: Wednesday, March 30, 2022 10:13 PM
> >
> > > From: Jason Gunthorpe
> > > Sent: Wednesday, March 30, 2022 7:58 PM
> > >
> > > On Wed, Mar 30, 2022 at 06:50:11AM +0000, Tian, Kevin wrote:
> > >
> > > > One thing that I'm not very sure is about DMA alias. Even when physically
> > > > there is only a single device within the group the aliasing could lead
> > > > to multiple RIDs in the group making it non-singleton. But probably we
> > > > don't need support SVA on such device until a real demand comes?
> > >
> > > How can we have multiple RIDs in the same group and have only one
> > > device in the group?
> >
> > Alex may help throw some insight here. Per what I read from the code
> > looks like certain device can generate traffic with multiple RIDs.
You only need to look so far as the dma alias quirks to find devices
that use the wrong RID for DMA. In general I don't think we have
enough confidence to say that for all these devices the wrong RID is
exclusively used versus some combination of both RIDs. Also, the
aliased RID is not always a physical device. Thanks,
Alex
next prev parent reply other threads:[~2022-03-30 15:04 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
2022-03-30 6:50 ` Tian, Kevin
2022-03-30 11:57 ` Lu Baolu
2022-03-30 11:58 ` Jason Gunthorpe
2022-03-30 14:12 ` Tian, Kevin
2022-03-30 14:30 ` Jason Gunthorpe
2022-04-02 7:12 ` Tian, Kevin
2022-04-02 23:29 ` Jason Gunthorpe
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 [this message]
2022-04-04 5:43 ` Lu Baolu
2022-04-04 17:24 ` Jason Gunthorpe
2022-04-05 6:12 ` Lu Baolu
2022-04-05 14:10 ` Jason Gunthorpe
2022-04-06 9:51 ` Lu Baolu
2022-04-01 6:20 ` Yi Liu
2022-04-01 11:52 ` Jason Gunthorpe
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
2022-04-02 8:43 ` Tian, Kevin
2022-04-02 23:32 ` Jason Gunthorpe
2022-04-04 6:09 ` Lu Baolu
2022-04-06 1:00 ` Tian, Kevin
2022-04-06 1:23 ` Jason Gunthorpe
2022-04-06 5:58 ` Tian, Kevin
2022-04-06 12:32 ` Robin Murphy
2022-04-06 13:06 ` Jason Gunthorpe
2022-04-06 13:37 ` Robin Murphy
2022-04-06 14:01 ` Jason Gunthorpe
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
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
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
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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