From: Jason Gunthorpe <jgg@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: "Liu, Yi L" <yi.l.liu@intel.com>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"eric.auger@redhat.com" <eric.auger@redhat.com>,
"nicolinc@nvidia.com" <nicolinc@nvidia.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"Duan, Zhenzhong" <zhenzhong.duan@intel.com>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>
Subject: Re: [PATCH v2 0/4] vfio-pci support pasid attach/detach
Date: Wed, 17 Apr 2024 09:20:51 -0300 [thread overview]
Message-ID: <20240417122051.GN3637727@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB5276E6975F78AE96F8DEC66D8C0F2@BN9PR11MB5276.namprd11.prod.outlook.com>
On Wed, Apr 17, 2024 at 07:16:05AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Wednesday, April 17, 2024 1:50 AM
> >
> > On Tue, Apr 16, 2024 at 08:38:50AM +0000, Tian, Kevin wrote:
> > > > From: Liu, Yi L <yi.l.liu@intel.com>
> > > > Sent: Friday, April 12, 2024 4:21 PM
> > > >
> > > > A userspace VMM is supposed to get the details of the device's PASID
> > > > capability
> > > > and assemble a virtual PASID capability in a proper offset in the virtual
> > PCI
> > > > configuration space. While it is still an open on how to get the available
> > > > offsets. Devices may have hidden bits that are not in the PCI cap chain.
> > For
> > > > now, there are two options to get the available offsets.[2]
> > > >
> > > > - Report the available offsets via ioctl. This requires device-specific logic
> > > > to provide available offsets. e.g., vfio-pci variant driver. Or may the
> > device
> > > > provide the available offset by DVSEC.
> > > > - Store the available offsets in a static table in userspace VMM. VMM gets
> > the
> > > > empty offsets from this table.
> > > >
> > >
> > > I'm not a fan of requesting a variant driver for every PASID-capable
> > > VF just for the purpose of reporting a free range in the PCI config space.
> > >
> > > It's easier to do that quirk in userspace.
> > >
> > > But I like Alex's original comment that at least for PF there is no reason
> > > to hide the offset. there could be a flag+field to communicate it. or
> > > if there will be a new variant VF driver for other purposes e.g. migration
> > > it can certainly fill the field too.
> >
> > Yes, since this has been such a sticking point can we get a clean
> > series that just enables it for PF and then come with a solution for
> > VF?
> >
>
> sure but we at least need to reach consensus on a minimal required
> uapi covering both PF/VF to move forward so the user doesn't need
> to touch different contracts for PF vs. VF.
Do we? The situation where the VMM needs to wholly make a up a PASID
capability seems completely new and seperate from just using an
existing PASID capability as in the PF case.
If it needs to make another system call or otherwise to do that then
that seems fine to do incrementally??
Jason
next prev parent reply other threads:[~2024-04-17 12:20 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-12 8:21 [PATCH v2 0/4] vfio-pci support pasid attach/detach Yi Liu
2024-04-12 8:21 ` [PATCH v2 1/4] ida: Add ida_get_lowest() Yi Liu
2024-04-16 16:03 ` Alex Williamson
2024-04-18 7:02 ` Yi Liu
2024-04-18 16:23 ` Alex Williamson
2024-04-18 17:12 ` Jason Gunthorpe
2024-04-19 13:43 ` Yi Liu
2024-04-19 13:55 ` Alex Williamson
2024-04-19 14:00 ` Jason Gunthorpe
2024-04-23 7:19 ` Yi Liu
2024-04-19 13:40 ` Yi Liu
2024-04-12 8:21 ` [PATCH v2 2/4] vfio-iommufd: Support pasid [at|de]tach for physical VFIO devices Yi Liu
2024-04-16 9:01 ` Tian, Kevin
2024-04-16 9:24 ` Yi Liu
2024-04-16 9:47 ` Tian, Kevin
2024-04-18 7:04 ` Yi Liu
2024-04-23 12:43 ` Jason Gunthorpe
2024-04-24 0:33 ` Tian, Kevin
2024-04-24 4:48 ` Yi Liu
2024-04-12 8:21 ` [PATCH v2 3/4] vfio: Add VFIO_DEVICE_PASID_[AT|DE]TACH_IOMMUFD_PT Yi Liu
2024-04-16 9:13 ` Tian, Kevin
2024-04-16 9:36 ` Yi Liu
2024-04-23 12:45 ` Jason Gunthorpe
2024-04-12 8:21 ` [PATCH v2 4/4] vfio: Report PASID capability via VFIO_DEVICE_FEATURE ioctl Yi Liu
2024-04-16 9:40 ` Tian, Kevin
2024-04-16 17:57 ` Alex Williamson
2024-04-17 7:09 ` Tian, Kevin
2024-04-17 20:25 ` Alex Williamson
2024-04-18 0:21 ` Tian, Kevin
2024-04-18 8:23 ` Yi Liu
2024-04-18 16:34 ` Alex Williamson
2024-04-23 12:39 ` Jason Gunthorpe
2024-04-24 0:24 ` Tian, Kevin
2024-04-24 13:59 ` Jason Gunthorpe
2024-04-16 8:38 ` [PATCH v2 0/4] vfio-pci support pasid attach/detach Tian, Kevin
2024-04-16 17:50 ` Jason Gunthorpe
2024-04-17 7:16 ` Tian, Kevin
2024-04-17 12:20 ` Jason Gunthorpe [this message]
2024-04-17 23:02 ` Alex Williamson
2024-04-18 0:06 ` Tian, Kevin
2024-04-18 9:03 ` Yi Liu
2024-04-18 20:37 ` Alex Williamson
2024-04-19 5:52 ` Tian, Kevin
2024-04-19 16:35 ` Alex Williamson
2024-04-23 7:43 ` Tian, Kevin
2024-04-23 12:01 ` Jason Gunthorpe
2024-04-23 23:47 ` Tian, Kevin
2024-04-24 0:12 ` Jason Gunthorpe
2024-04-24 2:57 ` Tian, Kevin
2024-04-24 12:29 ` Baolu Lu
2024-04-24 14:04 ` Jason Gunthorpe
2024-04-24 5:19 ` Tian, Kevin
2024-04-24 14:15 ` Jason Gunthorpe
2024-04-24 18:38 ` Alex Williamson
2024-04-24 18:45 ` Jason Gunthorpe
2024-04-24 18:24 ` Alex Williamson
2024-04-24 18:36 ` Jason Gunthorpe
2024-04-24 20:13 ` Alex Williamson
2024-04-26 14:11 ` Jason Gunthorpe
2024-04-26 20:13 ` Alex Williamson
2024-04-28 6:19 ` Tian, Kevin
2024-04-29 7:43 ` Yi Liu
2024-04-29 17:15 ` Jason Gunthorpe
2024-04-29 17:44 ` Jason Gunthorpe
2024-04-27 5:05 ` Christoph Hellwig
2024-04-25 9:26 ` Yi Liu
2024-04-25 12:58 ` Alex Williamson
2024-04-26 9:01 ` Yi Liu
2024-04-19 13:59 ` Jason Gunthorpe
2024-04-23 7:58 ` Yi Liu
2024-04-23 12:05 ` Jason Gunthorpe
2024-04-19 13:34 ` Jason Gunthorpe
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