Hi,

This series ostensibly adds virtio-user-gpio stubs to the build for
use with an external vhost-user daemon. We've been testing it with our
rust daemons from:

  https://github.com/rust-vmm/vhost-device

Getting the test enabled took some doing most likely because the need
for CONFIG support exercised additional paths in the code that were
not used for the simpler virtio-net tests. As a result the series has
a number of cleanup and documentation patches.

The final thing that needed fixing was the ensuring that
VHOST_USER_F_PROTOCOL_FEATURES didn't get squashed in the negotiation
process. This was the hardest thing to track down as we store the
feature bits in several places variously as:

  in VirtIODevice as:
    uint64_t guest_features;
    uint64_t host_features;
    uint64_t backend_features;

 in vhost_dev as:
    uint64_t features;
    uint64_t acked_features;
    uint64_t backend_features;

and a number of the other device structures also have various features
fields along with get/set function handlers. It wasn't super clear
what the flow through this structures was meant to be but I'm fairly
sure there is unnecessary duplication in there somewhere. We could
certainly do with some docstrings to make the point of each field
clear.

Going forward I wonder if having a fake vhost-user daemon is
sustainable in the long term. Maybe it would be better to spawn real
vhost-user daemons in a test mode so we don't end up duplicating the
whole protocol?

Anyway please review.

Alex Bennée (13):
  contrib/vhost-user-blk: fix 32 bit build and enable
  include/hw/virtio: more comment for VIRTIO_F_BAD_FEATURE
  include/hw/virtio: document vhost_get_features
  include/hw/virtio: document vhost_ack_features
  tests/qtest: pass stdout/stderr down to subtests
  tests/qtest: add a timeout for subprocess_run_one_test
  tests/qtest: use qos_printf instead of g_test_message
  tests/qtest: catch unhandled vhost-user messages
  tests/qtest: use g_autofree for test_server_create_chr
  tests/qtest: plain g_assert for VHOST_USER_F_PROTOCOL_FEATURES
  tests/qtest: implement stub for VHOST_USER_GET_CONFIG
  tests/qtest: add a get_features op to vhost-user-test
  tests/qtest: enable tests for virtio-gpio

Viresh Kumar (2):
  hw/virtio: add boilerplate for vhost-user-gpio device
  hw/virtio: add vhost-user-gpio-pci boilerplate

 meson.build                             |   2 +-
 include/hw/virtio/vhost-user-gpio.h     |  35 +++
 include/hw/virtio/vhost.h               |  21 ++
 include/hw/virtio/virtio.h              |   7 +-
 tests/qtest/libqos/virtio-gpio.h        |  35 +++
 contrib/vhost-user-blk/vhost-user-blk.c |   6 +-
 hw/virtio/vhost-user-gpio-pci.c         |  69 +++++
 hw/virtio/vhost-user-gpio.c             | 357 ++++++++++++++++++++++++
 tests/qtest/libqos/virtio-gpio.c        | 171 ++++++++++++
 tests/qtest/libqos/virtio.c             |   2 +-
 tests/qtest/qos-test.c                  |   8 +-
 tests/qtest/vhost-user-test.c           | 179 ++++++++++--
 contrib/vhost-user-blk/meson.build      |   3 +-
 hw/virtio/Kconfig                       |   5 +
 hw/virtio/meson.build                   |   2 +
 tests/qtest/libqos/meson.build          |   1 +
 16 files changed, 872 insertions(+), 31 deletions(-)
 create mode 100644 include/hw/virtio/vhost-user-gpio.h
 create mode 100644 tests/qtest/libqos/virtio-gpio.h
 create mode 100644 hw/virtio/vhost-user-gpio-pci.c
 create mode 100644 hw/virtio/vhost-user-gpio.c
 create mode 100644 tests/qtest/libqos/virtio-gpio.c

-- 
2.30.2

On Tue, May 24, 2022 at 04:40:41PM +0100, Alex Bennée wrote:
> Hi,
> 
> This series ostensibly adds virtio-user-gpio stubs to the build for
> use with an external vhost-user daemon. We've been testing it with our
> rust daemons from:
> 
>   https://github.com/rust-vmm/vhost-device
> 
> Getting the test enabled took some doing most likely because the need
> for CONFIG support exercised additional paths in the code that were
> not used for the simpler virtio-net tests. As a result the series has
> a number of cleanup and documentation patches.
> 
> The final thing that needed fixing was the ensuring that
> VHOST_USER_F_PROTOCOL_FEATURES didn't get squashed in the negotiation
> process. This was the hardest thing to track down as we store the
> feature bits in several places variously as:
> 
>   in VirtIODevice as:
>     uint64_t guest_features;
>     uint64_t host_features;
>     uint64_t backend_features;

None of these know about VHOST_USER_F_PROTOCOL_FEATURES and vhost-user's
unfiltered feature bits should never be passed to VirtIODevice.

> 
>  in vhost_dev as:
>     uint64_t features;
>     uint64_t acked_features;
>     uint64_t backend_features;

I don't think these should know about VHOST_USER_F_PROTOCOL_FEATURES
either. AFAIK vhost_dev deals with VIRTIO feature bits, not raw
vhost-user GET_FEATURES.

Stefan