Re: [Qemu-devel] [RFC ppc-next PATCH 3/6] memory: add memory_region_to_address()

[Alexander Graf]

On 14.02.2013, at 07:31, Scott Wood wrote:

> This is useful for when a user of the memory region API needs to
> communicate the absolute bus address to something outside QEMU
> (in particular, KVM).
> 
> Signed-off-by: Scott Wood <address@hidden>

Peter, how does the VGIC implementation handle this?


Alex

> ---
> include/exec/memory.h |    9 +++++++++
> memory.c              |   38 ++++++++++++++++++++++++++++++++++----
> 2 files changed, 43 insertions(+), 4 deletions(-)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 2322732..b800391 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -892,6 +892,15 @@ void *address_space_map(AddressSpace *as, hwaddr addr,
> void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
>                          int is_write, hwaddr access_len);
> 
> +/* memory_region_to_address: Find the full address of the start of the
> + *      given #MemoryRegion, ignoring aliases.  There is no guarantee
> + *      that the #MemoryRegion is actually visible at this address, if
> + *      there are overlapping regions.
> + *
> + * @mr: #MemoryRegion being queried
> + * @asp: if non-NULL, returns the #AddressSpace @mr is mapped in, if any
> + */
> +hwaddr memory_region_to_address(MemoryRegion *mr, AddressSpace **asp);
> 
> #endif
> 
> diff --git a/memory.c b/memory.c
> index cd7d5e0..0099f12 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -453,21 +453,51 @@ const IORangeOps memory_region_iorange_ops = {
>     .destructor = memory_region_iorange_destructor,
> };
> 
> -static AddressSpace *memory_region_to_address_space(MemoryRegion *mr)
> +static AddressSpace *memory_region_root_to_address_space(MemoryRegion *mr)
> {
>     AddressSpace *as;
> 
> -    while (mr->parent) {
> -        mr = mr->parent;
> -    }
>     QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
>         if (mr == as->root) {
>             return as;
>         }
>     }
> +
> +    return NULL;
> +}
> +
> +static AddressSpace *memory_region_to_address_space(MemoryRegion *mr)
> +{
> +    AddressSpace *as;
> +
> +    while (mr->parent) {
> +        mr = mr->parent;
> +    }
> +
> +    as = memory_region_root_to_address_space(mr);
> +    if (as) {
> +        return as;
> +    }
> +
>     abort();
> }
> 
> +hwaddr memory_region_to_address(MemoryRegion *mr, AddressSpace **asp)
> +{
> +    hwaddr addr = mr->addr;
> +
> +    while (mr->parent) {
> +        mr = mr->parent;
> +        addr += mr->addr;
> +    }
> +
> +    if (asp) {
> +        *asp = memory_region_root_to_address_space(mr);
> +    }
> +
> +    return addr;
> +}
> +
> /* Render a memory region into the global view.  Ranges in @view obscure
>  * ranges in @mr.
>  */
> -- 
> 1.7.9.5
> 
>