From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>
Cc: "Raj, Ashok" <ashok.raj@intel.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Jason Wang <jasowang@redhat.com>,
"Liu, Yi L" <yi.l.liu@intel.com>,
"eric.auger@redhat.com" <eric.auger@redhat.com>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
"Tian, Jun J" <jun.j.tian@intel.com>,
"Sun, Yi Y" <yi.y.sun@intel.com>,
"peterx@redhat.com" <peterx@redhat.com>,
"Wu, Hao" <hao.wu@intel.com>,
"stefanha@gmail.com" <stefanha@gmail.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Wed, 16 Sep 2020 01:19:18 +0000 [thread overview]
Message-ID: <MWHPR11MB1645934DB27033011316059B8C210@MWHPR11MB1645.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200915142906.GX904879@nvidia.com>
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, September 15, 2020 10:29 PM
>
> > Do they need a device at all? It's not clear to me why RID based
> > IOMMU management fits within vfio's scope, but PASID based does not.
>
> In RID mode vfio-pci completely owns the PCI function, so it is more
> natural that VFIO, as the sole device owner, would own the DMA mapping
> machinery. Further, the RID IOMMU mode is rarely used outside of VFIO
> so there is not much reason to try and disaggregate the API.
It is also used by vDPA.
>
> PASID on the other hand, is shared. vfio-mdev drivers will share the
> device with other kernel drivers. PASID and DMA will be concurrent
> with VFIO and other kernel drivers/etc.
>
Looks you are equating PASID to host-side sharing, while ignoring
another valid usage that a PASID-capable device is passed through
to the guest through vfio-pci and then PASID is used by the guest
for guest-side sharing. In such case, it is an exclusive usage in host
side and then what is the problem for VFIO to manage PASID given
that vfio-pci completely owns the function?
Thanks
Kevin
WARNING: multiple messages have this Message-ID (diff)
From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
"Raj, Ashok" <ashok.raj@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"stefanha@gmail.com" <stefanha@gmail.com>,
Jason Wang <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Tian, Jun J" <jun.j.tian@intel.com>,
"Sun, Yi Y" <yi.y.sun@intel.com>, "Wu, Hao" <hao.wu@intel.com>
Subject: RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Wed, 16 Sep 2020 01:19:18 +0000 [thread overview]
Message-ID: <MWHPR11MB1645934DB27033011316059B8C210@MWHPR11MB1645.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200915142906.GX904879@nvidia.com>
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, September 15, 2020 10:29 PM
>
> > Do they need a device at all? It's not clear to me why RID based
> > IOMMU management fits within vfio's scope, but PASID based does not.
>
> In RID mode vfio-pci completely owns the PCI function, so it is more
> natural that VFIO, as the sole device owner, would own the DMA mapping
> machinery. Further, the RID IOMMU mode is rarely used outside of VFIO
> so there is not much reason to try and disaggregate the API.
It is also used by vDPA.
>
> PASID on the other hand, is shared. vfio-mdev drivers will share the
> device with other kernel drivers. PASID and DMA will be concurrent
> with VFIO and other kernel drivers/etc.
>
Looks you are equating PASID to host-side sharing, while ignoring
another valid usage that a PASID-capable device is passed through
to the guest through vfio-pci and then PASID is used by the guest
for guest-side sharing. In such case, it is an exclusive usage in host
side and then what is the problem for VFIO to manage PASID given
that vfio-pci completely owns the function?
Thanks
Kevin
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-09-16 1:19 UTC|newest]
Thread overview: 165+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-10 10:45 [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 01/16] iommu: Report domain nesting info Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-11 19:38 ` Alex Williamson
2020-09-11 19:38 ` Alex Williamson
2020-09-10 10:45 ` [PATCH v7 02/16] iommu/smmu: Report empty " Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2021-01-12 6:50 ` Vivek Gautam
2021-01-12 6:50 ` Vivek Gautam
2021-01-12 9:21 ` Liu, Yi L
2021-01-12 9:21 ` Liu, Yi L
2021-01-12 11:05 ` Vivek Gautam
2021-01-12 11:05 ` Vivek Gautam
2021-01-13 5:56 ` Liu, Yi L
2021-01-13 5:56 ` Liu, Yi L
2021-01-19 10:03 ` Auger Eric
2021-01-19 10:03 ` Auger Eric
2021-01-23 8:59 ` Liu, Yi L
2021-01-23 8:59 ` Liu, Yi L
2021-02-12 7:14 ` Vivek Gautam
2021-02-12 7:14 ` Vivek Gautam
2021-02-12 9:57 ` Auger Eric
2021-02-12 9:57 ` Auger Eric
2021-02-12 10:18 ` Vivek Kumar Gautam
2021-02-12 10:18 ` Vivek Kumar Gautam
2021-02-12 11:01 ` Vivek Kumar Gautam
2021-02-12 11:01 ` Vivek Kumar Gautam
2021-03-03 9:44 ` Liu, Yi L
2021-03-03 9:44 ` Liu, Yi L
2020-09-10 10:45 ` [PATCH v7 03/16] vfio/type1: Report iommu nesting info to userspace Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-11 20:16 ` Alex Williamson
2020-09-11 20:16 ` Alex Williamson
2020-09-12 8:24 ` Liu, Yi L
2020-09-12 8:24 ` Liu, Yi L
2020-09-10 10:45 ` [PATCH v7 04/16] vfio: Add PASID allocation/free support Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-11 20:54 ` Alex Williamson
2020-09-11 20:54 ` Alex Williamson
2020-09-15 4:03 ` Liu, Yi L
2020-09-15 4:03 ` Liu, Yi L
2020-09-10 10:45 ` [PATCH v7 05/16] iommu/vt-d: Support setting ioasid set to domain Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 06/16] iommu/vt-d: Remove get_task_mm() in bind_gpasid() Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 07/16] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-11 21:38 ` Alex Williamson
2020-09-11 21:38 ` Alex Williamson
2020-09-12 6:17 ` Liu, Yi L
2020-09-10 10:45 ` [PATCH v7 08/16] iommu: Pass domain to sva_unbind_gpasid() Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 09/16] iommu/vt-d: Check ownership for PASIDs from user-space Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 10/16] vfio/type1: Support binding guest page tables to PASID Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-11 22:03 ` Alex Williamson
2020-09-11 22:03 ` Alex Williamson
2020-09-12 6:02 ` Liu, Yi L
2020-09-12 6:02 ` Liu, Yi L
2020-09-10 10:45 ` [PATCH v7 11/16] vfio/type1: Allow invalidating first-level/stage IOMMU cache Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 12/16] vfio/type1: Add vSVA support for IOMMU-backed mdevs Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 13/16] vfio/pci: Expose PCIe PASID capability to guest Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-11 22:13 ` Alex Williamson
2020-09-11 22:13 ` Alex Williamson
2020-09-12 7:17 ` Liu, Yi L
2020-09-12 7:17 ` Liu, Yi L
2020-09-10 10:45 ` [PATCH v7 14/16] vfio: Document dual stage control Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 15/16] iommu/vt-d: Only support nesting when nesting caps are consistent across iommu units Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-10 10:45 ` [PATCH v7 16/16] iommu/vt-d: Support reporting nesting capability info Liu Yi L
2020-09-10 10:45 ` Liu Yi L
2020-09-14 4:20 ` [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Jason Wang
2020-09-14 4:20 ` Jason Wang
2020-09-14 8:01 ` Tian, Kevin
2020-09-14 8:01 ` Tian, Kevin
2020-09-14 8:57 ` Jason Wang
2020-09-14 8:57 ` Jason Wang
2020-09-14 10:38 ` Tian, Kevin
2020-09-14 10:38 ` Tian, Kevin
2020-09-14 11:38 ` Jason Gunthorpe
2020-09-14 11:38 ` Jason Gunthorpe
2020-09-14 13:31 ` Jean-Philippe Brucker
2020-09-14 13:31 ` Jean-Philippe Brucker
2020-09-14 13:47 ` Jason Gunthorpe
2020-09-14 13:47 ` Jason Gunthorpe
2020-09-14 16:22 ` Raj, Ashok
2020-09-14 16:22 ` Raj, Ashok
2020-09-14 16:33 ` Jason Gunthorpe
2020-09-14 16:33 ` Jason Gunthorpe
2020-09-14 16:58 ` Alex Williamson
2020-09-14 16:58 ` Alex Williamson
2020-09-14 17:41 ` Jason Gunthorpe
2020-09-14 17:41 ` Jason Gunthorpe
2020-09-14 18:23 ` Alex Williamson
2020-09-14 18:23 ` Alex Williamson
2020-09-14 19:00 ` Jason Gunthorpe
2020-09-14 19:00 ` Jason Gunthorpe
2020-09-14 22:33 ` Alex Williamson
2020-09-14 22:33 ` Alex Williamson
2020-09-15 14:29 ` Jason Gunthorpe
2020-09-15 14:29 ` Jason Gunthorpe
2020-09-16 1:19 ` Tian, Kevin [this message]
2020-09-16 1:19 ` Tian, Kevin
2020-09-16 8:32 ` Jean-Philippe Brucker
2020-09-16 8:32 ` Jean-Philippe Brucker
2020-09-16 14:51 ` Jason Gunthorpe
2020-09-16 14:51 ` Jason Gunthorpe
2020-09-16 16:20 ` Jean-Philippe Brucker
2020-09-16 16:20 ` Jean-Philippe Brucker
2020-09-16 16:32 ` Jason Gunthorpe
2020-09-16 16:32 ` Jason Gunthorpe
2020-09-16 16:50 ` Auger Eric
2020-09-16 16:50 ` Auger Eric
2020-09-16 14:44 ` Jason Gunthorpe
2020-09-16 14:44 ` Jason Gunthorpe
2020-09-17 6:01 ` Tian, Kevin
2020-09-17 6:01 ` Tian, Kevin
2020-09-14 22:44 ` Raj, Ashok
2020-09-15 11:33 ` Jason Gunthorpe
2020-09-15 11:33 ` Jason Gunthorpe
2020-09-15 18:11 ` Raj, Ashok
2020-09-15 18:11 ` Raj, Ashok
2020-09-15 18:45 ` Jason Gunthorpe
2020-09-15 18:45 ` Jason Gunthorpe
2020-09-15 19:26 ` Raj, Ashok
2020-09-15 19:26 ` Raj, Ashok
2020-09-15 23:45 ` Jason Gunthorpe
2020-09-15 23:45 ` Jason Gunthorpe
2020-09-16 2:33 ` Jason Wang
2020-09-16 2:33 ` Jason Wang
2020-09-15 22:08 ` Jacob Pan
2020-09-15 22:08 ` Jacob Pan
2020-09-15 23:51 ` Jason Gunthorpe
2020-09-15 23:51 ` Jason Gunthorpe
2020-09-16 0:22 ` Jacob Pan (Jun)
2020-09-16 1:46 ` Lu Baolu
2020-09-16 1:46 ` Lu Baolu
2020-09-16 15:07 ` Jason Gunthorpe
2020-09-16 15:07 ` Jason Gunthorpe
2020-09-16 16:33 ` Raj, Ashok
2020-09-16 16:33 ` Raj, Ashok
2020-09-16 17:01 ` Jason Gunthorpe
2020-09-16 17:01 ` Jason Gunthorpe
2020-09-16 18:21 ` Jacob Pan (Jun)
2020-09-16 18:21 ` Jacob Pan (Jun)
2020-09-16 18:38 ` Jason Gunthorpe
2020-09-16 18:38 ` Jason Gunthorpe
2020-09-16 23:09 ` Jacob Pan (Jun)
2020-09-16 23:09 ` Jacob Pan (Jun)
2020-09-17 3:53 ` Jason Wang
2020-09-17 3:53 ` Jason Wang
2020-09-17 17:31 ` Jason Gunthorpe
2020-09-17 17:31 ` Jason Gunthorpe
2020-09-17 18:17 ` Jacob Pan (Jun)
2020-09-17 18:17 ` Jacob Pan (Jun)
2020-09-18 3:58 ` Jason Wang
2020-09-18 3:58 ` Jason Wang
2020-09-16 2:29 ` Jason Wang
2020-09-16 2:29 ` Jason Wang
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