Re: [PULL 6/9] virtio-gpu: fix v2 migration

[Fiona Ebner <f.ebner@proxmox.com>]

CC-ing stable, because this already is an issue in 9.0.0

Am 23.05.24 um 00:20 schrieb Fabiano Rosas:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> Commit dfcf74fa ("virtio-gpu: fix scanout migration post-load") broke
> forward/backward version migration. Versioning of nested VMSD structures
> is not straightforward, as the wire format doesn't have nested
> structures versions. Introduce x-scanout-vmstate-version and a field
> test to save/load appropriately according to the machine version.
> 
> Fixes: dfcf74fa ("virtio-gpu: fix scanout migration post-load")
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>
> Tested-by: Fiona Ebner <f.ebner@proxmox.com>
> [fixed long lines]
> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> ---
>  hw/core/machine.c              |  1 +
>  hw/display/virtio-gpu.c        | 30 ++++++++++++++++++++++--------
>  include/hw/virtio/virtio-gpu.h |  1 +
>  3 files changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index c7ceb11501..8d6dc69f0e 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -42,6 +42,7 @@ GlobalProperty hw_compat_8_2[] = {
>      { "migration", "zero-page-detection", "legacy"},
>      { TYPE_VIRTIO_IOMMU_PCI, "granule", "4k" },
>      { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
> +    { "virtio-gpu-device", "x-scanout-vmstate-version", "1" },
>  };
>  const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
>  
> diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
> index ae831b6b3e..d60b1b2973 100644
> --- a/hw/display/virtio-gpu.c
> +++ b/hw/display/virtio-gpu.c
> @@ -1166,10 +1166,17 @@ static void virtio_gpu_cursor_bh(void *opaque)
>      virtio_gpu_handle_cursor(&g->parent_obj.parent_obj, g->cursor_vq);
>  }
>  
> +static bool scanout_vmstate_after_v2(void *opaque, int version)
> +{
> +    struct VirtIOGPUBase *base = container_of(opaque, VirtIOGPUBase, scanout);
> +    struct VirtIOGPU *gpu = container_of(base, VirtIOGPU, parent_obj);
> +
> +    return gpu->scanout_vmstate_version >= 2;
> +}
> +
>  static const VMStateDescription vmstate_virtio_gpu_scanout = {
>      .name = "virtio-gpu-one-scanout",
> -    .version_id = 2,
> -    .minimum_version_id = 1,
> +    .version_id = 1,
>      .fields = (const VMStateField[]) {
>          VMSTATE_UINT32(resource_id, struct virtio_gpu_scanout),
>          VMSTATE_UINT32(width, struct virtio_gpu_scanout),
> @@ -1181,12 +1188,18 @@ static const VMStateDescription vmstate_virtio_gpu_scanout = {
>          VMSTATE_UINT32(cursor.hot_y, struct virtio_gpu_scanout),
>          VMSTATE_UINT32(cursor.pos.x, struct virtio_gpu_scanout),
>          VMSTATE_UINT32(cursor.pos.y, struct virtio_gpu_scanout),
> -        VMSTATE_UINT32_V(fb.format, struct virtio_gpu_scanout, 2),
> -        VMSTATE_UINT32_V(fb.bytes_pp, struct virtio_gpu_scanout, 2),
> -        VMSTATE_UINT32_V(fb.width, struct virtio_gpu_scanout, 2),
> -        VMSTATE_UINT32_V(fb.height, struct virtio_gpu_scanout, 2),
> -        VMSTATE_UINT32_V(fb.stride, struct virtio_gpu_scanout, 2),
> -        VMSTATE_UINT32_V(fb.offset, struct virtio_gpu_scanout, 2),
> +        VMSTATE_UINT32_TEST(fb.format, struct virtio_gpu_scanout,
> +                            scanout_vmstate_after_v2),
> +        VMSTATE_UINT32_TEST(fb.bytes_pp, struct virtio_gpu_scanout,
> +                            scanout_vmstate_after_v2),
> +        VMSTATE_UINT32_TEST(fb.width, struct virtio_gpu_scanout,
> +                            scanout_vmstate_after_v2),
> +        VMSTATE_UINT32_TEST(fb.height, struct virtio_gpu_scanout,
> +                            scanout_vmstate_after_v2),
> +        VMSTATE_UINT32_TEST(fb.stride, struct virtio_gpu_scanout,
> +                            scanout_vmstate_after_v2),
> +        VMSTATE_UINT32_TEST(fb.offset, struct virtio_gpu_scanout,
> +                            scanout_vmstate_after_v2),
>          VMSTATE_END_OF_LIST()
>      },
>  };
> @@ -1659,6 +1672,7 @@ static Property virtio_gpu_properties[] = {
>      DEFINE_PROP_BIT("blob", VirtIOGPU, parent_obj.conf.flags,
>                      VIRTIO_GPU_FLAG_BLOB_ENABLED, false),
>      DEFINE_PROP_SIZE("hostmem", VirtIOGPU, parent_obj.conf.hostmem, 0),
> +    DEFINE_PROP_UINT8("x-scanout-vmstate-version", VirtIOGPU, scanout_vmstate_version, 2),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
> index 56d6e821bf..7a59379f5a 100644
> --- a/include/hw/virtio/virtio-gpu.h
> +++ b/include/hw/virtio/virtio-gpu.h
> @@ -177,6 +177,7 @@ typedef struct VGPUDMABuf {
>  struct VirtIOGPU {
>      VirtIOGPUBase parent_obj;
>  
> +    uint8_t scanout_vmstate_version;
>      uint64_t conf_max_hostmem;
>  
>      VirtQueue *ctrl_vq;