Re: [PATCH 1/2] vhost: Don't pass ram device sections

[Roman Kagan]

On Wed, Jan 08, 2020 at 01:53:52PM +0000, Dr. David Alan Gilbert (git) wrote:
> Don't pass RAM blocks that are marked as ram devices to vhost.
> There's normally something special about them and they're not
> normally just shared memory.

Does this something special about them, whatever it is, make them
automatically ineligible for DMA?  Why should vhost ignore them?

/me goes reading what ram_device memory regions are...

Roman.

> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  hw/virtio/vhost.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 4da0d5a6c5..c81f0be71b 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -402,6 +402,7 @@ static bool vhost_section(struct vhost_dev *dev, 
> MemoryRegionSection *section)
>      bool log_dirty = memory_region_get_dirty_log_mask(section->mr) &
>                       ~(1 << DIRTY_MEMORY_MIGRATION);
>      result = memory_region_is_ram(section->mr) &&
> +        !memory_region_is_ram_device(section->mr) &&
>          !memory_region_is_rom(section->mr);
>  
>      /* Vhost doesn't handle any block which is doing dirty-tracking other
> -- 
> 2.24.1
> 
>