Re: [PATCH 0/2] virtio: Add vhost-user-gpio device's support

[Alex Bennée]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Thu, Jan 20, 2022 at 09:32:34AM +0530, Viresh Kumar wrote:
>> On 17-01-22, 10:11, Alex Bennée wrote:
>> > 
>> > "Michael S. Tsirkin" <mst@redhat.com> writes:
>> > 
>> > > On Wed, Jan 12, 2022 at 05:04:57PM +0530, Viresh Kumar wrote:
>> > >> Hello,
>> > >> 
>> > >> This patchset adds vhost-user-gpio device's support in Qemu. The 
>> > >> support for the
>> > >> same has already been added to virtio specification and Linux Kernel.
>> > >> 
>> > >> A Rust based backend is also in progress and is tested against this 
>> > >> patchset:
>> > >> 
>> > >> https://github.com/rust-vmm/vhost-device/pull/76
>> > >
>> > >
>> > > I'm reluctant to add this with no tests in tree.
>> > > Want to write a minimal libhost-user based backend?
>> 
>> I actually have one already, that I wrote before attempting the Rust
>> counterpart, but never upstreamed as I am not sure if anyone is ever
>> going to use it, as I am not. And I thought what's the point of
>> merging code which I will never end up using.
>> 
>> I am not sure what test I can add here to make sure this doesn't
>> breaks in future though.
>
> something that executes with make check.

With Eric's latest series
(20220118203833.316741-1-eric.auger@redhat.com) we are already
exercising most of the PCI code:

  ➜  gcov ./libqemu-aarch64-softmmu.fa.p/hw_virtio_vhost-user-gpio.c.gcda
  File '../../hw/virtio/vhost-user-gpio.c'
  Lines executed:10.43% of 163
  Creating 'vhost-user-gpio.c.gcov'

  File '/home/alex/lsrc/qemu.git/include/qemu/bitops.h'
  Lines executed:100.00% of 4
  Creating 'bitops.h.gcov'

  File '/home/alex/lsrc/qemu.git/include/hw/virtio/virtio.h'
  Lines executed:12.50% of 8
  Creating 'virtio.h.gcov'

  File '/home/alex/lsrc/qemu.git/include/hw/virtio/vhost-user-gpio.h'
  Lines executed:0.00% of 1
  Creating 'vhost-user-gpio.h.gcov'

  File '/home/alex/lsrc/qemu.git/include/hw/virtio/virtio-bus.h'
  Lines executed:0.00% of 1
  Creating 'virtio-bus.h.gcov'

  File '/home/alex/lsrc/qemu.git/include/hw/qdev-core.h'
  Lines executed:50.00% of 2
  Creating 'qdev-core.h.gcov'

  🕙15:40:35 alex@zen:qemu.git/builds/gprof  on  review/virtio-gpio-boilerplate 
[$?] 
  ➜  gcov ./libqemu-aarch64-softmmu.fa.p/hw_virtio_vhost-user-gpio-pci.c.gcda
  File '../../hw/virtio/vhost-user-gpio-pci.c'
  Lines executed:76.92% of 26
  Creating 'vhost-user-gpio-pci.c.gcov'

  File '/home/alex/lsrc/qemu.git/include/qemu/bitops.h'
  Lines executed:100.00% of 4
  Creating 'bitops.h.gcov'

  File '../../hw/virtio/virtio-pci.h'
  Lines executed:100.00% of 1
  Creating 'virtio-pci.h.gcov'

  File '/home/alex/lsrc/qemu.git/include/hw/pci/pci.h'
  Lines executed:100.00% of 1
  Creating 'pci.h.gcov'

  File '/home/alex/lsrc/qemu.git/include/hw/qdev-core.h'
  Lines executed:50.00% of 2
  Creating 'qdev-core.h.gcov'

So I think if we add the runes to ensure we instantiate both types
explicitly I think we will have enough coverage.

-- 
Alex Bennée