From: David Gibson <david@gibson.dropbear.id.au>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
"Alex Williamson (alex.williamson@redhat.com)"
<alex.williamson@redhat.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Jason Wang <jasowang@redhat.com>,
"parav@mellanox.com" <parav@mellanox.com>,
"Enrico Weigelt, metux IT consult" <lkml@metux.net>,
Paolo Bonzini <pbonzini@redhat.com>,
Shenming Lu <lushenming@huawei.com>,
Joerg Roedel <joro@8bytes.org>,
Eric Auger <eric.auger@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
"Raj, Ashok" <ashok.raj@intel.com>,
"Liu, Yi L" <yi.l.liu@intel.com>, "Wu, Hao" <hao.wu@intel.com>,
"Jiang, Dave" <dave.jiang@intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Robin Murphy <robin.murphy@arm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
David Woodhouse <dwmw2@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Lu Baolu <baolu.lu@linux.intel.com>
Subject: Re: [RFC v2] /dev/iommu uAPI proposal
Date: Tue, 10 Aug 2021 16:10:12 +1000 [thread overview]
Message-ID: <YRIYRI+2qSvX/e2d@yekko> (raw)
In-Reply-To: <20210806123211.GR1721383@nvidia.com>
[-- Attachment #1: Type: text/plain, Size: 2239 bytes --]
On Fri, Aug 06, 2021 at 09:32:11AM -0300, Jason Gunthorpe wrote:
> On Fri, Aug 06, 2021 at 02:45:26PM +1000, David Gibson wrote:
>
> > Well, that's kind of what I'm doing. PCI currently has the notion of
> > "default" address space for a RID, but there's no guarantee that other
> > buses (or even future PCI extensions) will. The idea is that
> > "endpoint" means exactly the (RID, PASID) or (SID, SSID) or whatever
> > future variations are on that.
>
> This is already happening in this proposal, it is why I insisted that
> the driver facing API has to be very explicit. That API specifies
> exactly what the device silicon is doing.
>
> However, that is placed at the IOASID level. There is no reason to
> create endpoint objects that are 1:1 with IOASID objects, eg for
> PASID.
They're not 1:1 though. You can have multiple endpoints in the same
IOAS, that's the whole point.
> We need to have clear software layers and responsibilities, I think
> this is where the VFIO container design has fallen behind.
>
> The device driver is responsible to delcare what TLPs the device it
> controls will issue
Right.. and I'm envisaging an endpoint as a abstraction to represent a
single TLP.
> The system layer is responsible to determine how those TLPs can be
> matched to IO page tables, if at all
>
> The IO page table layer is responsible to map the TLPs to physical
> memory.
>
> Each must stay in its box and we should not create objects that smush
> together, say, the device and system layers because it will only make
> a mess of the software design.
I agree... and endpoints are explicitly an attempt to do that. I
don't see how you think they're smushing things together.
> Since the system layer doesn't have any concrete objects in our
> environment (which is based on devices and IO page tables) it has to
> exist as metadata attached to the other two objects.
Whereas I'm suggesting clarifying this by *creating* concrete objects
to represent the concept we need.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2021-08-10 10:19 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 7:48 [RFC v2] /dev/iommu uAPI proposal Tian, Kevin
2021-07-09 21:50 ` Alex Williamson
2021-07-12 1:22 ` Tian, Kevin
2021-07-12 18:41 ` Alex Williamson
2021-07-12 23:41 ` Tian, Kevin
2021-07-12 23:56 ` Tian, Kevin
2021-07-13 12:55 ` Jason Gunthorpe
2021-07-13 16:26 ` Alex Williamson
2021-07-13 16:32 ` Jason Gunthorpe
2021-07-13 22:48 ` Tian, Kevin
2021-07-13 23:02 ` Jason Gunthorpe
2021-07-13 23:20 ` Tian, Kevin
2021-07-13 23:22 ` Jason Gunthorpe
2021-07-13 23:24 ` Tian, Kevin
2021-07-15 3:20 ` Shenming Lu
2021-07-15 3:55 ` Tian, Kevin
2021-07-15 6:29 ` Shenming Lu
2021-07-15 6:49 ` Tian, Kevin
2021-07-15 8:14 ` Shenming Lu
2021-07-15 12:48 ` Jason Gunthorpe
2021-07-15 13:57 ` Raj, Ashok
2021-07-15 15:23 ` Jason Gunthorpe
2021-07-15 16:21 ` Raj, Ashok
2021-07-15 17:18 ` Jason Gunthorpe
2021-07-15 17:48 ` Raj, Ashok
2021-07-15 17:53 ` Jason Gunthorpe
2021-07-15 18:05 ` Raj, Ashok
2021-07-15 18:13 ` Jason Gunthorpe
2021-07-16 1:20 ` Tian, Kevin
2021-07-16 12:20 ` Shenming Lu
2021-07-21 2:13 ` Tian, Kevin
2021-07-22 16:30 ` Jason Gunthorpe
2021-07-16 18:30 ` Jason Gunthorpe
2021-07-21 2:11 ` Tian, Kevin
2021-07-26 4:50 ` David Gibson
2021-07-28 4:04 ` Tian, Kevin
2021-08-03 1:50 ` David Gibson
2021-08-03 3:19 ` Tian, Kevin
2021-08-06 4:45 ` David Gibson
2021-08-06 12:32 ` Jason Gunthorpe
2021-08-10 6:10 ` David Gibson [this message]
2021-08-09 8:34 ` Tian, Kevin
2021-08-10 4:47 ` David Gibson
2021-08-10 6:04 ` Tian, Kevin
2021-07-30 14:51 ` Jason Gunthorpe
2021-08-02 2:49 ` Tian, Kevin
2021-08-04 14:04 ` Jason Gunthorpe
2021-08-04 22:59 ` Tian, Kevin
2021-08-05 11:27 ` Jason Gunthorpe
2021-08-05 22:44 ` Tian, Kevin
2021-08-06 4:47 ` David Gibson
2021-08-03 1:58 ` David Gibson
2021-08-04 14:07 ` Jason Gunthorpe
2021-08-06 4:24 ` David Gibson
2021-07-26 8:14 ` Jean-Philippe Brucker
2021-07-28 4:05 ` Tian, Kevin
2021-08-04 15:59 ` Eric Auger
2021-08-05 0:36 ` Tian, Kevin
2021-08-10 7:17 ` Eric Auger
2021-08-10 9:00 ` Tian, Kevin
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=YRIYRI+2qSvX/e2d@yekko \
--to=david@gibson.dropbear.id.au \
--cc=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=baolu.lu@linux.intel.com \
--cc=corbet@lwn.net \
--cc=dave.jiang@intel.com \
--cc=dwmw2@infradead.org \
--cc=eric.auger@redhat.com \
--cc=hao.wu@intel.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@linux.intel.com \
--cc=jasowang@redhat.com \
--cc=jean-philippe@linaro.org \
--cc=jgg@nvidia.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=kvm@vger.kernel.org \
--cc=kwankhede@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lkml@metux.net \
--cc=lushenming@huawei.com \
--cc=parav@mellanox.com \
--cc=pbonzini@redhat.com \
--cc=robin.murphy@arm.com \
--cc=yi.l.liu@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).