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From: Jason Gunthorpe <jgg@nvidia.com>
To: "joro@8bytes.org" <joro@8bytes.org>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	Jason Wang <jasowang@redhat.com>,
	"Liu, Yi L" <yi.l.liu@intel.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"eric.auger@redhat.com" <eric.auger@redhat.com>,
	"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
	"jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Tian, Jun J" <jun.j.tian@intel.com>,
	"Sun, Yi Y" <yi.y.sun@intel.com>,
	"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
	"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: (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Tue, 3 Nov 2020 09:23:35 -0400	[thread overview]
Message-ID: <20201103132335.GO2620339@nvidia.com> (raw)
In-Reply-To: <20201103131852.GE22888@8bytes.org>

On Tue, Nov 03, 2020 at 02:18:52PM +0100, joro@8bytes.org wrote:
> On Tue, Nov 03, 2020 at 08:56:43AM -0400, Jason Gunthorpe wrote:
> > On Tue, Nov 03, 2020 at 10:52:09AM +0100, joro@8bytes.org wrote:
> > > So having said this, what is the benefit of exposing those SVA internals
> > > to user-space?
> > 
> > Only the device use of the PASID is device specific, the actual PASID
> > and everything on the IOMMU side is generic.
> > 
> > There is enough API there it doesn't make sense to duplicate it into
> > every single SVA driver.
> 
> What generic things have to be done by the drivers besides
> allocating/deallocating PASIDs and binding an address space to it?
> 
> Is there anything which isn't better handled in a kernel-internal
> library which drivers just use?

Userspace needs fine grained control over the composition of the page
table behind the PASID, 1:1 with the mm_struct is only one use case.

Userspace needs to be able to handle IOMMU faults, apparently

The Intel guys had a bunch of other stuff too, looking through the new
API they are proposing for vfio gives some flavour what they think is
needed..

Jason

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: "joro@8bytes.org" <joro@8bytes.org>
Cc: "jean-philippe@linaro.org" <jean-philippe@linaro.org>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"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>,
	"Sun, Yi Y" <yi.y.sun@intel.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"Wu, Hao" <hao.wu@intel.com>,
	"Tian, Jun J" <jun.j.tian@intel.com>
Subject: Re: (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Tue, 3 Nov 2020 09:23:35 -0400	[thread overview]
Message-ID: <20201103132335.GO2620339@nvidia.com> (raw)
In-Reply-To: <20201103131852.GE22888@8bytes.org>

On Tue, Nov 03, 2020 at 02:18:52PM +0100, joro@8bytes.org wrote:
> On Tue, Nov 03, 2020 at 08:56:43AM -0400, Jason Gunthorpe wrote:
> > On Tue, Nov 03, 2020 at 10:52:09AM +0100, joro@8bytes.org wrote:
> > > So having said this, what is the benefit of exposing those SVA internals
> > > to user-space?
> > 
> > Only the device use of the PASID is device specific, the actual PASID
> > and everything on the IOMMU side is generic.
> > 
> > There is enough API there it doesn't make sense to duplicate it into
> > every single SVA driver.
> 
> What generic things have to be done by the drivers besides
> allocating/deallocating PASIDs and binding an address space to it?
> 
> Is there anything which isn't better handled in a kernel-internal
> library which drivers just use?

Userspace needs fine grained control over the composition of the page
table behind the PASID, 1:1 with the mm_struct is only one use case.

Userspace needs to be able to handle IOMMU faults, apparently

The Intel guys had a bunch of other stuff too, looking through the new
API they are proposing for vfio gives some flavour what they think is
needed..

Jason
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2020-11-03 13:23 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12  8:38 (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Tian, Kevin
2020-10-12  8:38 ` Tian, Kevin
2020-10-13  6:22 ` Jason Wang
2020-10-13  6:22   ` Jason Wang
2020-10-14  3:08   ` Tian, Kevin
2020-10-14  3:08     ` Tian, Kevin
2020-10-14 23:10     ` Alex Williamson
2020-10-14 23:10       ` Alex Williamson
2020-10-15  7:02       ` Jason Wang
2020-10-15  7:02         ` Jason Wang
2020-10-15  6:52     ` Jason Wang
2020-10-15  6:52       ` Jason Wang
2020-10-15  7:58       ` Tian, Kevin
2020-10-15  7:58         ` Tian, Kevin
2020-10-15  8:40         ` Jason Wang
2020-10-15  8:40           ` Jason Wang
2020-10-15 10:14           ` Liu, Yi L
2020-10-15 10:14             ` Liu, Yi L
2020-10-20  6:18             ` Jason Wang
2020-10-20  6:18               ` Jason Wang
2020-10-20  8:19               ` Liu, Yi L
2020-10-20  8:19                 ` Liu, Yi L
2020-10-20  9:19                 ` Jason Wang
2020-10-20  9:19                   ` Jason Wang
2020-10-20  9:40                   ` Liu, Yi L
2020-10-20  9:40                     ` Liu, Yi L
2020-10-20 13:54                     ` Jason Gunthorpe
2020-10-20 13:54                       ` Jason Gunthorpe
2020-10-20 14:00                       ` Liu, Yi L
2020-10-20 14:00                         ` Liu, Yi L
2020-10-20 14:05                         ` Jason Gunthorpe
2020-10-20 14:05                           ` Jason Gunthorpe
2020-10-20 14:09                           ` Liu, Yi L
2020-10-20 14:09                             ` Liu, Yi L
2020-10-13 10:27 ` Jean-Philippe Brucker
2020-10-13 10:27   ` Jean-Philippe Brucker
2020-10-14  2:11   ` Tian, Kevin
2020-10-14  2:11     ` Tian, Kevin
2020-10-14  3:16 ` Tian, Kevin
2020-10-14  3:16   ` Tian, Kevin
2020-10-16 15:36   ` Jason Gunthorpe
2020-10-16 15:36     ` Jason Gunthorpe
2020-10-19  8:39     ` Liu, Yi L
2020-10-19  8:39       ` Liu, Yi L
2020-10-19 14:25       ` Jason Gunthorpe
2020-10-19 14:25         ` Jason Gunthorpe
2020-10-20 10:21         ` Liu, Yi L
2020-10-20 10:21           ` Liu, Yi L
2020-10-20 14:02           ` Jason Gunthorpe
2020-10-20 14:02             ` Jason Gunthorpe
2020-10-20 14:19             ` Liu, Yi L
2020-10-20 14:19               ` Liu, Yi L
2020-10-21  2:21               ` Jason Wang
2020-10-21  2:21                 ` Jason Wang
2020-10-20 16:24             ` Raj, Ashok
2020-10-20 16:24               ` Raj, Ashok
2020-10-20 17:03               ` Jason Gunthorpe
2020-10-20 17:03                 ` Jason Gunthorpe
2020-10-20 19:51                 ` Raj, Ashok
2020-10-20 19:51                   ` Raj, Ashok
2020-10-20 19:55                   ` Jason Gunthorpe
2020-10-20 19:55                     ` Jason Gunthorpe
2020-10-20 20:08                     ` Raj, Ashok
2020-10-20 20:08                       ` Raj, Ashok
2020-10-20 20:14                       ` Jason Gunthorpe
2020-10-20 20:14                         ` Jason Gunthorpe
2020-10-20 20:27                         ` Raj, Ashok
2020-10-20 20:27                           ` Raj, Ashok
2020-10-21 11:48                           ` Jason Gunthorpe
2020-10-21 11:48                             ` Jason Gunthorpe
2020-10-21 17:51                             ` Raj, Ashok
2020-10-21 17:51                               ` Raj, Ashok
2020-10-21 18:24                               ` Jason Gunthorpe
2020-10-21 18:24                                 ` Jason Gunthorpe
2020-10-21 20:03                                 ` Raj, Ashok
2020-10-21 20:03                                   ` Raj, Ashok
2020-10-21 23:32                                   ` Jason Gunthorpe
2020-10-21 23:32                                     ` Jason Gunthorpe
2020-10-21 23:53                                     ` Raj, Ashok
2020-10-21 23:53                                       ` Raj, Ashok
2020-10-22  2:55                               ` Jason Wang
2020-10-22  2:55                                 ` Jason Wang
2020-10-22  3:54                                 ` Liu, Yi L
2020-10-22  3:54                                   ` Liu, Yi L
2020-10-22  4:38                                   ` Jason Wang
2020-10-22  4:38                                     ` Jason Wang
2020-11-03  9:52 ` joro
2020-11-03  9:52   ` joro
2020-11-03 12:56   ` Jason Gunthorpe
2020-11-03 12:56     ` Jason Gunthorpe
2020-11-03 13:18     ` joro
2020-11-03 13:18       ` joro
2020-11-03 13:23       ` Jason Gunthorpe [this message]
2020-11-03 13:23         ` Jason Gunthorpe
2020-11-03 14:03         ` joro
2020-11-03 14:03           ` joro
2020-11-03 14:06           ` Jason Gunthorpe
2020-11-03 14:06             ` Jason Gunthorpe
2020-11-03 14:35             ` joro
2020-11-03 14:35               ` joro
2020-11-03 15:22               ` Jason Gunthorpe
2020-11-03 15:22                 ` Jason Gunthorpe
2020-11-03 16:55                 ` joro
2020-11-03 16:55                   ` joro
2020-11-03 17:48                   ` Jason Gunthorpe
2020-11-03 17:48                     ` Jason Gunthorpe
2020-11-03 19:14                     ` joro
2020-11-03 19:14                       ` joro
2020-11-04 19:29                       ` Jason Gunthorpe
2020-11-04 19:29                         ` Jason Gunthorpe

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