Re: [Qemu-devel] [RFC] virtio-mmio: implement modern (v2) personality (virtio-1)

[Andrea Bolognani]

On Mon, 2019-07-29 at 14:57 +0200, Sergio Lopez wrote:
[...]
>  /* virtio-mmio device */
>  
>  static Property virtio_mmio_properties[] = {
>      DEFINE_PROP_BOOL("format_transport_address", VirtIOMMIOProxy,
>                       format_transport_address, true),
> +    DEFINE_PROP_BOOL("modern", VirtIOMMIOProxy, modern, false),
>      DEFINE_PROP_END_OF_LIST(),
>  };

Not a QEMU developer so forgive me if I say something silly, but IIUC
you'd be able to opt into the new feature by using eg.

  -device virtio-net-device,modern=on

However, virtio-pci devices already have a mechanism to control the
VirtIO protocol version, where you use

  -device virtio-net-pci,disable-modern=no,disable-legacy=yes

to get a VirtIO 1.x-only device and

  -device virtio-net-pci,disable-modern=no,disable-legacy=no

for a transitional device.

Can you please make sure virtio-mmio uses the existing interface
instead of introducing a new one?

-- 
Andrea Bolognani / Red Hat / Virtualization