From: Alex Williamson <alex.williamson@redhat.com>
To: Matthew Rosato <mjrosato@linux.ibm.com>
Cc: "Cornelia Huck" <cohuck@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Libvirt Devel" <libvir-list@redhat.com>,
"Kirti Wankhede" <kwankhede@nvidia.com>,
"Erik Skultety" <eskultet@redhat.com>,
"Pavel Hrdina" <phrdina@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Sylvain Bauza" <sbauza@redhat.com>,
"Christophe de Dinechin" <dinechin@redhat.com>,
"Tony Krowiak" <akrowiak@linux.ibm.com>
Subject: Re: mdevctl: A shoestring mediated device management and persistence utility
Date: Thu, 27 Jun 2019 09:38:32 -0600 [thread overview]
Message-ID: <20190627093832.064a346f@x1.home> (raw)
In-Reply-To: <06114b39-69c2-3fa0-d0b3-aa96a44ae2ce@linux.ibm.com>
On Thu, 27 Jun 2019 11:00:31 -0400
Matthew Rosato <mjrosato@linux.ibm.com> wrote:
> On 6/27/19 8:26 AM, Cornelia Huck wrote:
> > On Wed, 26 Jun 2019 19:53:50 -0600
> > Alex Williamson <alex.williamson@redhat.com> wrote:
> >
> >> On Wed, 26 Jun 2019 08:37:20 -0600
> >> Alex Williamson <alex.williamson@redhat.com> wrote:
> >>
> >>> On Wed, 26 Jun 2019 11:58:06 +0200
> >>> Cornelia Huck <cohuck@redhat.com> wrote:
> >>>
> >>>> On Tue, 25 Jun 2019 16:52:51 -0600
> >>>> Alex Williamson <alex.williamson@redhat.com> wrote:
> >>>>
> >>>>> Hi,
> >>>>>
> >>>>> Based on the discussions we've had, I've rewritten the bulk of
> >>>>> mdevctl. I think it largely does everything we want now, modulo
> >>>>> devices that will need some sort of 1:N values per key for
> >>>>> configuration in the config file versus the 1:1 key:value setup we
> >>>>> currently have (so don't consider the format final just yet).
> >>>>
> >>>> We might want to factor out that config format handling while we're
> >>>> trying to finalize it.
> >>>>
> >>>> cc:ing Matt for his awareness. I'm currently not quite sure how to
> >>>> handle those vfio-ap "write several values to an attribute one at a
> >>>> time" requirements. Maybe 1:N key:value is the way to go; maybe we
> >>>> need/want JSON or something like that.
> >>>
> >>> Maybe we should just do JSON for future flexibility. I assume there
> >>> are lots of helpers that should make it easy even from a bash script.
> >>> I'll look at that next.
> >>
> >> Done. Throw away any old mdev config files, we use JSON now.
> >
> > The code changes look quite straightforward, thanks.
> >
> >> The per
> >> mdev config now looks like this:
> >>
> >> {
> >> "mdev_type": "i915-GVTg_V4_8",
> >> "start": "auto"
> >> }
> >>
> >> My expectation, and what I've already pre-enabled support in set_key
> >> and get_key functions, is that we'd use arrays for values, so we might
> >> have:
> >>
> >> "new_key": ["value1", "value2"]
> >>
> >> set_key will automatically convert a comma separated list of values
> >> into such an array, so I'm thinking this would be specified by the user
> >> as:
> >>
> >> # mdevctl modify -u UUID --key=new_key --value=value1,value2
> >
> > Looks sensible.
> >
> > For vfio-ap, we'd probably end up with something like the following:
> >
> > {
> > "mdev_type": "vfio_ap-passthrough",
> > "start": "auto",
> > "assign_adapter": ["5", "6"],
> > "assign_domain": ["4", "0xab"]
> > }
> >
> > (following the Guest1 example in the kernel documentation)
> >
> > <As an aside, what should happen if e.g "assign_adapter" is set to
> > ["6", "7"]? Remove 5, add 7? Remove all values, then set the new ones?
>
> IMO remove 5, add 7 would make the most sense. I'm not sure that doing
> an unassign of all adapters (effectively removing all APQNs) followed by
> an assign of the new ones would work nicely with Tony's vfio-ap dynamic
> configuration patches.
Are we conflating operating on the config file versus operating on the
device? I was thinking that setting a new key value replaces the
existing key, because anything else adds unnecessary complication to
the code and command line. So in the above example, if the user
specified:
mdevctl modify -u UUID --key=assign_adapter --value=6,7
The new value is simply ["6", "7"]. This would take effect the next
time the device is started. We haven't yet considered how to change
running devices, but I think the semantics we have since the respin of
mdevctl separate saved config vs running devices in order to generalize
the support of transient devices.
> > Similar for deleting the "assign_adapter" key. We have an
> > "unassign_adapter" attribute, but this is not something we can infer
> > automatically; we need to know that we're dealing with an vfio-ap
> > matrix device...>
> >
> >>
> >> We should think about whether ordering is important and maybe
> >> incorporate that into key naming conventions or come up with some
> >> syntax for specifying startup blocks. Thanks,
> >>
> >> Alex
> >
> > Hm...
> >
> > {
> > "foo": "1",
> > "bar": "42",
> > "baz": {
> > "depends": ["foo", "bar"],
> > "value": "plahh"
> > }
> > }
> >
> > Something like that?
I'm not sure yet. I think we need to look at what's feasible (and
easy) with jq. Thanks,
Alex
next prev parent reply other threads:[~2019-06-27 15:38 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 23:20 mdevctl: A shoestring mediated device management and persistence utility Alex Williamson
2019-05-24 10:11 ` Cornelia Huck
2019-05-24 14:43 ` Alex Williamson
2019-06-07 16:06 ` Halil Pasic
2019-06-11 19:45 ` Cornelia Huck
2019-06-11 20:28 ` Alex Williamson
2019-06-12 7:14 ` Cornelia Huck
2019-06-12 15:54 ` Halil Pasic
2019-06-13 10:02 ` Cornelia Huck
2019-06-12 15:07 ` Halil Pasic
2019-06-13 16:17 ` Christophe de Dinechin
2019-06-13 16:35 ` Alex Williamson
2019-06-14 9:54 ` [libvirt] " Christophe de Dinechin
2019-06-14 14:23 ` Alex Williamson
2019-06-14 15:06 ` Christophe de Dinechin
2019-06-14 16:04 ` Alex Williamson
2019-06-17 16:03 ` Cornelia Huck
2019-06-17 14:00 ` Daniel P. Berrangé
2019-06-17 14:54 ` Alex Williamson
2019-06-17 15:10 ` Daniel P. Berrangé
2019-06-17 17:05 ` Alex Williamson
2019-06-18 8:44 ` Daniel P. Berrangé
2019-06-18 11:01 ` Cornelia Huck
[not found] ` <CALOCmukPWiXiM+mN0hCTvSwfdHy5UdERU8WnvOXiBrMQ9tH3VA@mail.gmail.com>
2019-06-18 22:12 ` Alex Williamson
2019-06-19 7:28 ` Daniel P. Berrangé
2019-06-19 9:46 ` Cornelia Huck
2019-06-19 18:46 ` Alex Williamson
2019-06-20 8:24 ` Daniel P. Berrangé
[not found] ` <CALOCmu=6Xmw-_-SVXujCEcgPY2CQiBQKgfUMJ45WnZ_9XORyUw@mail.gmail.com>
2019-06-19 9:57 ` Cornelia Huck
2019-06-19 19:53 ` Alex Williamson
2019-06-25 22:52 ` Alex Williamson
2019-06-26 9:58 ` Cornelia Huck
2019-06-26 14:37 ` Alex Williamson
2019-06-27 1:53 ` Alex Williamson
2019-06-27 12:26 ` Cornelia Huck
2019-06-27 15:00 ` Matthew Rosato
2019-06-27 15:38 ` Alex Williamson [this message]
2019-06-27 16:13 ` Matthew Rosato
2019-06-27 21:15 ` Alex Williamson
2019-06-28 1:57 ` Alex Williamson
2019-06-28 9:06 ` Cornelia Huck
2019-06-28 14:01 ` Matthew Rosato
2019-06-28 17:05 ` Alex Williamson
2019-07-01 8:20 ` Cornelia Huck
2019-07-01 14:40 ` Alex Williamson
2019-07-01 17:13 ` Cornelia Huck
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=20190627093832.064a346f@x1.home \
--to=alex.williamson@redhat.com \
--cc=akrowiak@linux.ibm.com \
--cc=berrange@redhat.com \
--cc=cohuck@redhat.com \
--cc=dinechin@redhat.com \
--cc=eskultet@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=kwankhede@nvidia.com \
--cc=libvir-list@redhat.com \
--cc=mjrosato@linux.ibm.com \
--cc=phrdina@redhat.com \
--cc=sbauza@redhat.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).