Messages in this thread | | | Date | Fri, 18 Mar 2022 20:01:04 +0800 | From | Lu Baolu <> | Subject | Re: [PATCH v2 2/8] iommu: Add attach/detach_dev_pasid domain ops |
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On 2022/3/15 19:49, Tian, Kevin wrote: >> From: Jean-Philippe Brucker<jean-philippe@linaro.org> >> Sent: Tuesday, March 15, 2022 7:27 PM >> >> On Mon, Mar 14, 2022 at 10:07:06PM -0700, Jacob Pan wrote: >>> From: Lu Baolu<baolu.lu@linux.intel.com> >>> >>> An IOMMU domain represents an address space which can be attached by >>> devices that perform DMA within a domain. However, for platforms with >>> PASID capability the domain attachment needs be handled at device+PASID >>> level. There can be multiple PASIDs within a device and multiple devices >>> attached to a given domain. >>> This patch introduces a new IOMMU op which support device, PASID, and >>> IOMMU domain attachment. The immediate use case is for PASID capable >>> devices to perform DMA under DMA APIs. >>> >>> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com> >>> Signed-off-by: Jacob Pan<jacob.jun.pan@linux.intel.com> >>> --- >>> include/linux/iommu.h | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >>> index 369f05c2a4e2..fde5b933dbe3 100644 >>> --- a/include/linux/iommu.h >>> +++ b/include/linux/iommu.h >>> @@ -227,6 +227,8 @@ struct iommu_iotlb_gather { >>> * @aux_get_pasid: get the pasid given an aux-domain >>> * @sva_bind: Bind process address space to device >>> * @sva_unbind: Unbind process address space from device >>> + * @attach_dev_pasid: attach an iommu domain to a pasid of device >>> + * @detach_dev_pasid: detach an iommu domain from a pasid of device >> Isn't that operation "assign a PASID to a domain" instead? In patch 5, >> the domain is already attached to the device, so set_domain_pasid() might >> be clearer and to the point. If the IOMMU driver did the allocation we >> could also avoid patch 1. > iiuc this API can also work for future SIOV usage where each mdev attached > to the domain has its own pasid. "assigning a PASID to a domain" sounds > like going back to the previous aux domain approach which has one PASID > per domain and that PASID is used on all devices attached to the aux domain... >
This also works for SVA as far as I can see. The sva_bind essentially is to attach an SVA domain to the PASID of a device. The sva_bind/unbind ops could be removed with these two new callbacks.
Best regards, baolu
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