From: Jason Gunthorpe <jgg@nvidia.com>
To: "Raj, Ashok" <ashok.raj@intel.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
Jason Wang <jasowang@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
<alex.williamson@redhat.com>, <eric.auger@redhat.com>,
<baolu.lu@linux.intel.com>, <joro@8bytes.org>,
<kevin.tian@intel.com>, <jacob.jun.pan@linux.intel.com>,
<jun.j.tian@intel.com>, <yi.y.sun@intel.com>, <peterx@redhat.com>,
<hao.wu@intel.com>, <stefanha@gmail.com>,
<iommu@lists.linux-foundation.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: Mon, 14 Sep 2020 13:33:54 -0300 [thread overview]
Message-ID: <20200914163354.GG904879@nvidia.com> (raw)
In-Reply-To: <20200914162247.GA63399@otc-nc-03>
On Mon, Sep 14, 2020 at 09:22:47AM -0700, Raj, Ashok wrote:
> Hi Jason,
>
> On Mon, Sep 14, 2020 at 10:47:38AM -0300, Jason Gunthorpe wrote:
> > On Mon, Sep 14, 2020 at 03:31:13PM +0200, Jean-Philippe Brucker wrote:
> >
> > > > Jason suggest something like /dev/sva. There will be a lot of other
> > > > subsystems that could benefit from this (e.g vDPA).
> > >
> > > Do you have a more precise idea of the interface /dev/sva would provide,
> > > how it would interact with VFIO and others? vDPA could transport the
> > > generic iommu.h structures via its own uAPI, and call the IOMMU API
> > > directly without going through an intermediate /dev/sva handle.
> >
> > Prior to PASID IOMMU really only makes sense as part of vfio-pci
> > because the iommu can only key on the BDF. That can't work unless the
> > whole PCI function can be assigned. It is hard to see how a shared PCI
> > device can work with IOMMU like this, so may as well use vfio.
> >
> > SVA and various vIOMMU models change this, a shared PCI driver can
> > absoultely work with a PASID that is assigned to a VM safely, and
> > actually don't need to know if their PASID maps a mm_struct or
> > something else.
>
> Well, IOMMU does care if its a native mm_struct or something that belongs
> to guest. Because you need ability to forward page-requests and pickup
> page-responses from guest. Since there is just one PRQ on the IOMMU and
> responses can't be sent directly. You have to depend on vIOMMU type
> interface in guest to make all of this magic work right?
Yes, IOMMU cares, but not the PCI Driver. It just knows it has a
PASID. Details on how page faultings is handled or how the mapping is
setup is abstracted by the PASID.
> > This new PASID allocator would match the guest memory layout and
>
> Not sure what you mean by "match guest memory layout"?
> Probably, meaning first level is gVA or gIOVA?
It means whatever the qemu/viommu/guest/etc needs across all the
IOMMU/arch implementations.
Basically, there should only be two ways to get a PASID
- From mm_struct that mirrors the creating process
- Via '/dev/sva' which has an complete interface to create and
control a PASID suitable for virtualization and more
VFIO should not have its own special way to get a PASID.
Jason
next prev parent reply other threads:[~2020-09-14 16:34 UTC|newest]
Thread overview: 81+ 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
2020-09-10 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 [this message]
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
[not found] ` <20200914224438.GA65940@otc-nc-03>
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
[not found] ` <20200915171319.00003f59@linux.intel.com>
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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