[Libosinfo] [PATCH osinfo-db 0/5 v2] Add q35 devices

[Cole Robinson]

The main goal of this series is to advertise q35 chipset and device
support for suitable OS. Some details about the individual decisions

* We group q35+ich9+e1000e together. This likely isn't completely
  accurate but in the virt case I think it only makes sense to
  specify the latter two devices when pcie (q35) is present, so
  I went with it.

* We only advertise q35 when virtio1.0 devices are available, on linux.
  This definitely isn't accurate, q35 predates virtio1.0 by 8 years or
  so, but there's issues combining q35 with legacy virtio, and that's
  the only combo I'll be exploring for virt-manager so other scenarios
  my go untested.

* The actual OS+q35 combos are largely untested by me.

v1 posting:
https://www.redhat.com/archives/libosinfo/2018-August/msg00006.html

v2 changes:
    * Rebased, drop committed patches
    * Rework the chipset device ID and dir structure


In the original posting danpb suggested introducing a new <chipset>
concept to cover this case, roughly outlined here:

https://www.redhat.com/archives/libosinfo/2018-September/msg00014.html

This posting doesn't add that and instead uses <device> like before,
but with some changes:

$ cat data/device/qemu.org/chipset-x86_64-q35.d/class.xml.in
<libosinfo version="0.0.1">
<!-- Licensed under the GNU General Public License version 2 or later.
     See http://www.gnu.org/licenses/ for a copy of the license text -->
  <device id="http://qemu.org/chipset/x86_64/q35">
    <name>q35</name>
    <class>chipset.virtual</class>
  </device>
</libosinfo>


My justifications for not going the full <chipset> route:

* It's much more work to add new APIs, test them, document them, etc.
  I'm lazy, but it's also a lot more code to maintain forever.

* Will be harder in the short term for clients as well. virt-manager
  will need to use the new APIs and correctly check that they exist,
  vs just using the existing device APIs.

* I think we should bite the bullet and make the <device> concept
  more fuzzy, since we may want that anyways to model things like
  hyperv features which aren't all strictly devices.

* Eventually we will need to extend the XML schema with some way to
  mark <devices> unsupported if a new version of an OS drops support.
  This is already the case with newer windows which doesn't support
  ac97 out of the box, though libosinfo still reports support. If
  we have a separate <chipset> concept, we will need to duplicate
  that schema and likely libosinfo support to handle that case as
  well. So more work going forward.


Now some questions: A quick one: is class=chipset.virtual okay? I
used .virtual as some day we may want to track actual chipset PCI
devices for example, like the PCI ID for q35.

Bigger question: What is the expected way that API users should
determine if libosinfo supports a particular device? Take USB tablet
support for example. The qemu usb tablet has this device xml:

  <device id="http://usb.org/usb/80ee/0021">
    <name>tablet</name>
    <class>input</class>
  </device>

Ways you can presently search for that device with the API:

- Search for the device ID which is expected to be unique
- Search for name=tablet which presently is unique. However that's a
  super generic name, and nothing seems to enforce <name> uniqueness
  for devices, so I don't know if we can/should count on that.
- Search for class=input name=tablet which narrows it a bit

virt-manager for example does the last step. I don't know if that's
a good idea though, given how generic name is. Do we aim to give
any guarantees about <name> uniqueness, or that it will never change?
Is <class> never expected to change?

With that context, let's consider querying chipset. I want to make
sure this syntax isn't going to make future virt chipset additions
difficult. Dan's list in the email lays out some other examples:

     qemu.org/chipset/i686-q35
     qemu.org/chipset/x86_64-q35
     qemu.org/chipset/aarch64/virt
     qemu.org/chipset/riscv/virt

If <name> is expected to be globally unique, we probably don't want
to use name=q35 incase it clashes with a future pcisig.com <device>,
another virt stack's chipset, or even qemu q35 for i686. So that could
mean name=x86_64-q35, or even name=qemu-x86_64-q35. That gets ugly and
redundant fast though.

So IMO the sensible thing would be to enforce uniqueness in two ways:
1) the device ID, 2) the set of all device properties. So that would lead
to these 4 configs

  <device id="http://qemu.org/chipset/x86_64/q35">
    <name>q35</name>
    <arch>x86_64</arch>
    <class>chipset.virtual</class>
  </device>
  <device id="http://qemu.org/chipset/i686/q35">
    <name>q35</name>
    <arch>i686</arch>
    <class>chipset.virtual</class>
  </device>
  <device id="http://qemu.org/chipset/aarch64/virt">
    <name>virt</name>
    <arch>aarch64</arch>
    <class>chipset.virtual</class>
  </device>
  <device id="http://qemu.org/chipset/riscv/virt">
    <name>virt</name>
    <arch>riscv</arch>
    <class>chipset.virtual</class>
  </device>


The downsides of that: 1) if an app naively searchs for name=q35 they
may get the wrong result, because it ignored <arch>. Easy to misuse.
2) There aren't any other examples yet of non-unique <name> so maybe
it causes other issues.

All of that makes me think that the only safe recommendation for apps
is to search by device id. <name> should be treated largely as metadata.

We don't necessarily need to implement all this now, since the q35 case
is fairly straightforward, but we should at least make sure we aren't
going down the wrong path.



Cole Robinson (5):
  device: Add network e1000e
  device: Add sound ich9
  device: Add chipset q35
  os: Add q35/e1000e/ich9 for win2k8r2+ and win7+
  os: linux: Add q35/ich9/e1000e alongside virtio1.0 <device>

 data/device/pcisig.com/pci-8086-10d3.d/class.xml.in    | 8 ++++++++
 data/device/pcisig.com/pci-8086-293e.d/class.xml.in    | 8 ++++++++
 data/device/qemu.org/chipset-x86_64-q35.d/class.xml.in | 8 ++++++++
 data/os/debian.org/debian-9.xml.in                     | 3 +++
 data/os/fedoraproject.org/fedora-23.xml.in             | 5 ++++-
 data/os/microsoft.com/win-2k8r2.xml.in                 | 6 ++++++
 data/os/microsoft.com/win-7.xml.in                     | 3 +++
 data/os/opensuse.org/opensuse-42.2.xml.in              | 3 +++
 data/os/redhat.com/rhel-7.2.xml.in                     | 3 +++
 data/os/suse.com/sled-12.2.xml.in                      | 3 +++
 data/os/suse.com/sles-12.2.xml.in                      | 3 +++
 data/os/ubuntu.com/ubuntu-17.04.xml.in                 | 3 +++
 data/schema/osinfo.rng.in                              | 1 +
 13 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 data/device/pcisig.com/pci-8086-10d3.d/class.xml.in
 create mode 100644 data/device/pcisig.com/pci-8086-293e.d/class.xml.in
 create mode 100644 data/device/qemu.org/chipset-x86_64-q35.d/class.xml.in

-- 
2.17.1