Re: [Qemu-devel] [PATCH RFC v3 1/2] memory: allow MemoryRegion's priority field to accept negative values

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Sep 09, 2013 at 02:21:35PM +0300, Marcel Apfelbaum wrote:
> Priority is used to make visible some subregions by obscuring
> the parent MemoryRegion addresses overlapping with the subregion.
> 
> By allowing the priority to be negative the opposite can be done:
> Allow a subregion to be visible on all the addresses not covered
> by the parent MemoryRegion or other subregions.
> 
> Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>

Seems harmless enough.

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>


> ---
>  include/exec/memory.h | 6 +++---
>  memory.c              | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index ebe0d24..6995087 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -153,7 +153,7 @@ struct MemoryRegion {
>      bool flush_coalesced_mmio;
>      MemoryRegion *alias;
>      hwaddr alias_offset;
> -    unsigned priority;
> +    int priority;
>      bool may_overlap;
>      QTAILQ_HEAD(subregions, MemoryRegion) subregions;
>      QTAILQ_ENTRY(MemoryRegion) subregions_link;
> @@ -193,7 +193,7 @@ struct MemoryListener {
>      void (*coalesced_mmio_del)(MemoryListener *listener, MemoryRegionSection *section,
>                                 hwaddr addr, hwaddr len);
>      /* Lower = earlier (during add), later (during del) */
> -    unsigned priority;
> +    int priority;
>      AddressSpace *address_space_filter;
>      QTAILQ_ENTRY(MemoryListener) link;
>  };
> @@ -779,7 +779,7 @@ void memory_region_add_subregion(MemoryRegion *mr,
>  void memory_region_add_subregion_overlap(MemoryRegion *mr,
>                                           hwaddr offset,
>                                           MemoryRegion *subregion,
> -                                         unsigned priority);
> +                                         int priority);
>  
>  /**
>   * memory_region_get_ram_addr: Get the ram address associated with a memory
> diff --git a/memory.c b/memory.c
> index 5a10fd0..984a3dc 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1473,7 +1473,7 @@ void memory_region_add_subregion(MemoryRegion *mr,
>  void memory_region_add_subregion_overlap(MemoryRegion *mr,
>                                           hwaddr offset,
>                                           MemoryRegion *subregion,
> -                                         unsigned priority)
> +                                         int priority)
>  {
>      subregion->may_overlap = true;
>      subregion->priority = priority;
> -- 
> 1.8.3.1