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From: Jason Gunthorpe <jgg@nvidia.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: yi.y.sun@intel.com,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	kevin.tian@intel.com, "Raj, Ashok" <ashok.raj@intel.com>,
	kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
	stefanha@gmail.com, Jason Wang <jasowang@redhat.com>,
	jun.j.tian@intel.com,
	Alex Williamson <alex.williamson@redhat.com>,
	iommu@lists.linux-foundation.org,
	Jacon Jun Pan <jacob.jun.pan@intel.com>,
	hao.wu@intel.com
Subject: Re: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Tue, 15 Sep 2020 20:51:26 -0300	[thread overview]
Message-ID: <20200915235126.GK1573713@nvidia.com> (raw)
In-Reply-To: <20200915150851.76436ca1@jacob-builder>

On Tue, Sep 15, 2020 at 03:08:51PM -0700, Jacob Pan wrote:
> > A PASID vIOMMU solution sharable with VDPA and VFIO, based on a PASID
> > control char dev (eg /dev/sva, or maybe /dev/iommu) seems like a
> > reasonable starting point for discussion.
> 
> I am not sure what can really be consolidated in /dev/sva. 

More or less, everything in this patch. All the manipulations of PASID
that are required for vIOMMU use case/etc. Basically all PASID control
that is not just a 1:1 mapping of the mm_struct.

> will have their own kerne-user interfaces anyway for their usage models.
> They are just providing the specific transport while sharing generic IOMMU
> UAPIs and IOASID management.

> As I mentioned PASID management is already consolidated in the IOASID layer,
> so for VDPA or other users, it just matter of create its own ioasid_set,
> doing allocation.

Creating the PASID is not the problem, managing what the PASID maps to
is the issue. That is all uAPI that we don't really have today.

> IOASID is also available to the in-kernel users which does not
> need /dev/sva AFAICT. For bare metal SVA, I don't see a need to create this
> 'floating' state of the PASID when created by /dev/sva. PASID allocation
> could happen behind the scene when users need to bind page tables to a
> device DMA stream.

My point is I would like to see one set of uAPI ioctls to bind page
tables. I don't want to have VFIO, VDPA, etc, etc uAPIs to do the exact
same things only slightly differently.

If user space wants to bind page tables, create the PASID with
/dev/sva, use ioctls there to setup the page table the way it wants,
then pass the now configured PASID to a driver that can use it. 

Driver does not do page table binding. Do not duplicate all the
control plane uAPI in every driver.

PASID managment and binding is seperated from the driver(s) that are
using the PASID.

Jason
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  reply	other threads:[~2020-09-15 23:51 UTC|newest]

Thread overview: 84+ 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 ` [PATCH v7 01/16] iommu: Report domain nesting info Liu Yi L
2020-09-11 19:38   ` Alex Williamson
2020-09-10 10:45 ` [PATCH v7 02/16] iommu/smmu: Report empty " Liu Yi L
2021-01-12  6:50   ` Vivek Gautam
2021-01-12  9:21     ` Liu, Yi L
2021-01-12 11:05       ` Vivek Gautam
2021-01-13  5:56         ` Liu, Yi L
2021-01-19 10:03           ` Auger Eric
2021-01-23  8:59             ` Liu, Yi L
2021-02-12  7:14               ` Vivek Gautam
2021-02-12  9:57                 ` Auger Eric
2021-02-12 10:18                   ` Vivek Kumar Gautam
2021-02-12 11:01                     ` Vivek Kumar Gautam
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
2020-09-11 20:16   ` Alex Williamson
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
2020-09-11 20:54   ` Alex Williamson
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 ` [PATCH v7 06/16] iommu/vt-d: Remove get_task_mm() in bind_gpasid() Liu Yi L
2020-09-10 10:45 ` [PATCH v7 07/16] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Liu Yi L
2020-09-11 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 ` [PATCH v7 09/16] iommu/vt-d: Check ownership for PASIDs from user-space Liu Yi L
2020-09-10 10:45 ` [PATCH v7 10/16] vfio/type1: Support binding guest page tables to PASID Liu Yi L
2020-09-11 22:03   ` Alex Williamson
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 ` [PATCH v7 12/16] vfio/type1: Add vSVA support for IOMMU-backed mdevs Liu Yi L
2020-09-10 10:45 ` [PATCH v7 13/16] vfio/pci: Expose PCIe PASID capability to guest Liu Yi L
2020-09-11 22:13   ` Alex Williamson
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 ` [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 ` [PATCH v7 16/16] iommu/vt-d: Support reporting nesting capability info 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  8:01   ` Tian, Kevin
2020-09-14  8:57     ` Jason Wang
2020-09-14 10:38       ` Tian, Kevin
2020-09-14 11:38         ` Jason Gunthorpe
2020-09-14 13:31   ` Jean-Philippe Brucker
2020-09-14 13:47     ` Jason Gunthorpe
2020-09-14 16:22       ` Raj, Ashok
2020-09-14 16:33         ` Jason Gunthorpe
2020-09-14 16:58           ` Alex Williamson
2020-09-14 17:41             ` Jason Gunthorpe
2020-09-14 18:23               ` Alex Williamson
2020-09-14 19:00                 ` Jason Gunthorpe
2020-09-14 22:33                   ` Alex Williamson
2020-09-15 14:29                     ` Jason Gunthorpe
2020-09-16  1:19                       ` Tian, Kevin
2020-09-16  8:32                         ` Jean-Philippe Brucker
2020-09-16 14:51                           ` Jason Gunthorpe
2020-09-16 16:20                             ` Jean-Philippe Brucker
2020-09-16 16:32                               ` Jason Gunthorpe
2020-09-16 16:50                                 ` Auger Eric
2020-09-16 14:44                         ` Jason Gunthorpe
2020-09-17  6:01                           ` Tian, Kevin
2020-09-14 22:44                   ` Raj, Ashok
2020-09-15 11:33                     ` Jason Gunthorpe
2020-09-15 18:11                       ` Raj, Ashok
2020-09-15 18:45                         ` Jason Gunthorpe
2020-09-15 19:26                           ` Raj, Ashok
2020-09-15 23:45                             ` Jason Gunthorpe
2020-09-16  2:33                             ` Jason Wang
2020-09-15 22:08                           ` Jacob Pan
2020-09-15 23:51                             ` Jason Gunthorpe [this message]
2020-09-16  0:22                               ` Jacob Pan (Jun)
2020-09-16  1:46                                 ` Lu Baolu
2020-09-16 15:07                                 ` Jason Gunthorpe
2020-09-16 16:33                                   ` Raj, Ashok
2020-09-16 17:01                                     ` Jason Gunthorpe
2020-09-16 18:21                                       ` Jacob Pan (Jun)
2020-09-16 18:38                                         ` Jason Gunthorpe
2020-09-16 23:09                                           ` Jacob Pan (Jun)
2020-09-17  3:53                                             ` Jason Wang
2020-09-17 17:31                                               ` Jason Gunthorpe
2020-09-17 18:17                                               ` Jacob Pan (Jun)
2020-09-18  3:58                                                 ` Jason Wang
2020-09-16  2:29     ` Jason Wang

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