Re: [PATCH] virtio-pmem-pci: force virtio version 1

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 25 Sep 2020 12:22:51 +0200
Pankaj Gupta <pankaj.gupta.linux@gmail.com> wrote:

>  Qemu fails with below error when trying to run with virtio pmem:
> 
>  (qemu) qemu-system-x86_64: -device virtio-pmem-pci,memdev=mem1,id=nv1:
>   device is modern-only, use disable-legacy=on

Oh, another one :(

>  
>  This patch fixes this by forcing virtio 1 with virtio-pmem.
> 
> fixes: adf0748a49 ("virtio-pci: Proxy for virtio-pmem")
> Signed-off-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> ---
>  hw/virtio/virtio-pmem-pci.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/virtio/virtio-pmem-pci.c b/hw/virtio/virtio-pmem-pci.c
> index 21a457d151..2b2a0b1eae 100644
> --- a/hw/virtio/virtio-pmem-pci.c
> +++ b/hw/virtio/virtio-pmem-pci.c
> @@ -22,6 +22,7 @@ static void virtio_pmem_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>      VirtIOPMEMPCI *pmem_pci = VIRTIO_PMEM_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&pmem_pci->vdev);
>  
> +    virtio_pci_force_virtio_1(vpci_dev);
>      qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
>  }
>  

The alternative would be to force virtio 1 only for 5.1 and later (see
https://lore.kernel.org/qemu-devel/20200921122506.82515-1-sgarzare@redhat.com/).