Re: [PATCH] virtio: Fix virtio_mmio_read()/virtio_mmio_write()

[Laurent Vivier]

Hi,

could this fix be merged in QEMU 6.0?

Thanks,
Laurent

Le 14/03/2021 à 21:03, Laurent Vivier a écrit :
> Both functions don't check the personality of the interface (legacy or
> modern) before accessing the configuration memory and always use
> virtio_config_readX()/virtio_config_writeX().
> 
> With this patch, they now check the personality and in legacy mode
> call virtio_config_readX()/virtio_config_writeX(), otherwise call
> virtio_config_modern_readX()/virtio_config_modern_writeX().
> 
> This change has been tested with virtio-mmio guests (virt stretch/armhf and
> virt sid/m68k) and virtio-pci guests (pseries RHEL-7.3/ppc64 and /ppc64le).
> 
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  hw/virtio/virtio-mmio.c | 74 +++++++++++++++++++++++++++++------------
>  1 file changed, 52 insertions(+), 22 deletions(-)
> 
> diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
> index 6990b9879cf0..342c918ea7b7 100644
> --- a/hw/virtio/virtio-mmio.c
> +++ b/hw/virtio/virtio-mmio.c
> @@ -112,15 +112,28 @@ static uint64_t virtio_mmio_read(void *opaque, hwaddr 
> offset, unsigned size)
>  
>      if (offset >= VIRTIO_MMIO_CONFIG) {
>          offset -= VIRTIO_MMIO_CONFIG;
> -        switch (size) {
> -        case 1:
> -            return virtio_config_readb(vdev, offset);
> -        case 2:
> -            return virtio_config_readw(vdev, offset);
> -        case 4:
> -            return virtio_config_readl(vdev, offset);
> -        default:
> -            abort();
> +        if (proxy->legacy) {
> +            switch (size) {
> +            case 1:
> +                return virtio_config_readb(vdev, offset);
> +            case 2:
> +                return virtio_config_readw(vdev, offset);
> +            case 4:
> +                return virtio_config_readl(vdev, offset);
> +            default:
> +                abort();
> +            }
> +        } else {
> +            switch (size) {
> +            case 1:
> +                return virtio_config_modern_readb(vdev, offset);
> +            case 2:
> +                return virtio_config_modern_readw(vdev, offset);
> +            case 4:
> +                return virtio_config_modern_readl(vdev, offset);
> +            default:
> +                abort();
> +            }
>          }
>      }
>      if (size != 4) {
> @@ -245,20 +258,37 @@ static void virtio_mmio_write(void *opaque, hwaddr 
> offset, uint64_t value,
>  
>      if (offset >= VIRTIO_MMIO_CONFIG) {
>          offset -= VIRTIO_MMIO_CONFIG;
> -        switch (size) {
> -        case 1:
> -            virtio_config_writeb(vdev, offset, value);
> -            break;
> -        case 2:
> -            virtio_config_writew(vdev, offset, value);
> -            break;
> -        case 4:
> -            virtio_config_writel(vdev, offset, value);
> -            break;
> -        default:
> -            abort();
> +        if (proxy->legacy) {
> +            switch (size) {
> +            case 1:
> +                virtio_config_writeb(vdev, offset, value);
> +                break;
> +            case 2:
> +                virtio_config_writew(vdev, offset, value);
> +                break;
> +            case 4:
> +                virtio_config_writel(vdev, offset, value);
> +                break;
> +            default:
> +                abort();
> +            }
> +            return;
> +        } else {
> +            switch (size) {
> +            case 1:
> +                virtio_config_modern_writeb(vdev, offset, value);
> +                break;
> +            case 2:
> +                virtio_config_modern_writew(vdev, offset, value);
> +                break;
> +            case 4:
> +                virtio_config_modern_writel(vdev, offset, value);
> +                break;
> +            default:
> +                abort();
> +            }
> +            return;
>          }
> -        return;
>      }
>      if (size != 4) {
>          qemu_log_mask(LOG_GUEST_ERROR,
>