Re: [PATCH vfio 11/11] vfio/virtio: Introduce a vfio driver over virtio devices

["Michael S. Tsirkin" <mst@redhat.com>]

>  MAINTAINERS                      |   6 +
>  drivers/vfio/pci/Kconfig         |   2 +
>  drivers/vfio/pci/Makefile        |   2 +
>  drivers/vfio/pci/virtio/Kconfig  |  15 +
>  drivers/vfio/pci/virtio/Makefile |   4 +
>  drivers/vfio/pci/virtio/cmd.c    |   4 +-
>  drivers/vfio/pci/virtio/cmd.h    |   8 +
>  drivers/vfio/pci/virtio/main.c   | 546 +++++++++++++++++++++++++++++++
>  8 files changed, 585 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/vfio/pci/virtio/Kconfig
>  create mode 100644 drivers/vfio/pci/virtio/Makefile
>  create mode 100644 drivers/vfio/pci/virtio/main.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index bf0f54c24f81..5098418c8389 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22624,6 +22624,12 @@ L:	kvm@vger.kernel.org
>  S:	Maintained
>  F:	drivers/vfio/pci/mlx5/
>  
> +VFIO VIRTIO PCI DRIVER
> +M:	Yishai Hadas <yishaih@nvidia.com>
> +L:	kvm@vger.kernel.org
> +S:	Maintained
> +F:	drivers/vfio/pci/virtio
> +
>  VFIO PCI DEVICE SPECIFIC DRIVERS
>  R:	Jason Gunthorpe <jgg@nvidia.com>
>  R:	Yishai Hadas <yishaih@nvidia.com>

Tying two subsystems together like this is going to cause pain when
merging. God forbid there's something e.g. virtio net specific
(and there's going to be for sure) - now we are talking 3 subsystems.

Case in point all other virtio drivers are nicely grouped, have a common
mailing list etc etc.  This one is completely separate to the point
where people won't even remember to copy the virtio mailing list.


diff --git a/drivers/vfio/pci/virtio/Kconfig b/drivers/vfio/pci/virtio/Kconfig
new file mode 100644
index 000000000000..89eddce8b1bd
--- /dev/null
+++ b/drivers/vfio/pci/virtio/Kconfig
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config VIRTIO_VFIO_PCI
+        tristate "VFIO support for VIRTIO PCI devices"
+        depends on VIRTIO_PCI
+        select VFIO_PCI_CORE
+        help
+          This provides support for exposing VIRTIO VF devices using the VFIO
+          framework that can work with a legacy virtio driver in the guest.
+          Based on PCIe spec, VFs do not support I/O Space; thus, VF BARs shall
+          not indicate I/O Space.
+          As of that this driver emulated I/O BAR in software to let a VF be
+          seen as a transitional device in the guest and let it work with
+          a legacy driver.
+
+          If you don't know what to do here, say N.

I don't promise we'll remember to poke at vfio if we tweak something
in the virtio kconfig.

-- 
MST

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