Re: [PATCH 2/3] xen/virtual-region: Include rodata pointers

[Jan Beulich <jbeulich@xxxxxxxx>]

On 05.03.2024 13:11, Andrew Cooper wrote:
> --- a/xen/include/xen/virtual_region.h
> +++ b/xen/include/xen/virtual_region.h
> @@ -16,6 +16,9 @@ struct virtual_region
>      const void *text_start;                /* .text virtual address start. */
>      const void *text_end;                  /* .text virtual address end. */
>  
> +    const void *rodata_start;              /* .rodata virtual address start 
> (optional). */
> +    const void *rodata_end;                /* .rodata virtual address end. */
> +
>      /* If this is NULL the default lookup mechanism is used. */
>      symbols_lookup_t *symbols_lookup;

While perhaps the least bad one can do without quite a bit more churn,
I'm still irritated by a virtual region (singular) suddenly covering
two ranges of VA space. At the very least I think the description should
say a word of justification in this regard. An alternative, after all,
could have been for livepatch code to register separate regions for
rodata (if present in a patch).

A follow-on question then would be why ordinary data isn't reflected in
a virtual region. Aiui that's just because livepatch presently has no
need for it.

Underlying question to both: Is the virtual region concept indeed meant
to be fully tied to livepatch and its needs?

Jan