Re: [Qemu-devel] [PATCH for-1.7 v2 1/8] exec: declare TARGET_PHYS_ADDR_SPACE_MAX to limit memory regions rendered by exec

[Peter Maydell <peter.maydell@linaro.org>]

On 7 November 2013 10:41, Marcel Apfelbaum <marcel.a@redhat.com> wrote:
> The page table logic in exec.c assumes
> that memory addresses are at most TARGET_PHYS_ADDR_SPACE_BITS.
> Use TARGET_PHYS_ADDR_SPACE_MAX as max size for memory regions
> rendered by exec.
>
> Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
> ---
>  include/exec/address-spaces.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/exec/address-spaces.h b/include/exec/address-spaces.h
> index 3d12cdd..174cc05 100644
> --- a/include/exec/address-spaces.h
> +++ b/include/exec/address-spaces.h
> @@ -23,6 +23,10 @@
>
>  #ifndef CONFIG_USER_ONLY
>
> +#define TARGET_PHYS_ADDR_SPACE_MAX                         \
> +    (TARGET_PHYS_ADDR_SPACE_BITS == 64 ?                   \
> +    UINT64_MAX : (0x1ULL << TARGET_PHYS_ADDR_SPACE_BITS))
> +

I think it's worth adding a comment that this is a
size intended for use in memory_region_init() calls and
so follows the odd convention used by that API that
it is a size in bytes with the exception that UINT64_MAX
represents 2^64.

(it follows from this that using the #define anywhere
except in a memory_region_init() call is probably a bug)

-- PMM