From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
"Liu, Yi L" <yi.l.liu@intel.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, 24 Apr 2024 02:57:38 +0000 [thread overview]
Message-ID: <BN9PR11MB5276555B3294D5A0892043E98C102@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20240424001221.GF941030@nvidia.com>
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Wednesday, April 24, 2024 8:12 AM
>
> On Tue, Apr 23, 2024 at 11:47:50PM +0000, Tian, Kevin wrote:
> > > From: Jason Gunthorpe <jgg@nvidia.com>
> > > Sent: Tuesday, April 23, 2024 8:02 PM
> > >
> > > On Tue, Apr 23, 2024 at 07:43:27AM +0000, Tian, Kevin wrote:
> > > > I'm not sure how userspace can fully handle this w/o certain assistance
> > > > from the kernel.
> > > >
> > > > So I kind of agree that emulated PASID capability is probably the only
> > > > contract which the kernel should provide:
> > > > - mapped 1:1 at the physical location, or
> > > > - constructed at an offset according to DVSEC, or
> > > > - constructed at an offset according to a look-up table
> > > >
> > > > The VMM always scans the vfio pci config space to expose vPASID.
> > > >
> > > > Then the remaining open is what VMM could do when a VF supports
> > > > PASID but unfortunately it's not reported by vfio. W/o the capability
> > > > of inspecting the PASID state of PF, probably the only feasible option
> > > > is to maintain a look-up table in VMM itself and assumes the kernel
> > > > always enables the PASID cap on PF.
> > >
> > > I'm still not sure I like doing this in the kernel - we need to do the
> > > same sort of thing for ATS too, right?
> >
> > VF is allowed to implement ATS.
> >
> > PRI has the same problem as PASID.
>
> I'm surprised by this, I would have guessed ATS would be the device
> global one, PRI not being per-VF seems problematic??? How do you
> disable PRI generation to get a clean shutdown?
Here is what the PCIe spec says:
For SR-IOV devices, a single Page Request Interface is permitted for
the PF and is shared between the PF and its associated VFs, in which
case the PF implements this capability and its VFs must not.
I'll let Baolu chime in for the potential impact to his PRI cleanup
effort, e.g. whether disabling PRI generation is mandatory if the
IOMMU side is already put in a mode auto-responding error to
new PRI request instead of reporting to sw.
But I do see another problem for shared capabilities between PF/VFs.
Now those shared capabilities are enabled/disabled when the PF is
attached to/detached from a domain, w/o counting the shared usage
from VFs.
Looks we have a gap here.
next prev parent reply other threads:[~2024-04-24 2:58 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BN9PR11MB5276555B3294D5A0892043E98C102@BN9PR11MB5276.namprd11.prod.outlook.com \
--to=kevin.tian@intel.com \
--cc=alex.williamson@redhat.com \
--cc=baolu.lu@linux.intel.com \
--cc=chao.p.peng@linux.intel.com \
--cc=eric.auger@redhat.com \
--cc=iommu@lists.linux.dev \
--cc=jacob.jun.pan@intel.com \
--cc=jgg@nvidia.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=nicolinc@nvidia.com \
--cc=robin.murphy@arm.com \
--cc=yi.l.liu@intel.com \
--cc=zhenzhong.duan@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.