>>> On 14.02.18 at 08:15, <blacksk...@gmail.com> wrote:
> Hi Jan,
> 2018-02-13 23:26 GMT+08:00 Jan Beulich <jbeul...@suse.com>:
>>>>> On 13.02.18 at 16:15, <blacksk...@gmail.com> wrote:
>>> I've updated the comments according to your previous suggestions,
>>> do they look good to you?
>> The one in the public header is way too verbose. I specifically don't
>> see why you would need to spell out XSM privilege requirements
>> there. Please make new comments match existing ones in style and
>> verbosity if at all possible, while still conveying all necessary /
>> relevant information.
> I shortened it a little bit, and now it looks like:
> #define XENMAPSPACE_gmfn_share 6 /* GMFN from another dom. Unlike
> if (c) tries to map pages from (t) into
> (d), this doesn't require that (d)
> has the privilege to map the pages, but
> instead requires that (c) has the
> privilege to do so, as long as (d) and
> are allowed to share memory pages.
> This is XENMEM_add_to_physmap_batch
> and currently ARM only. */
Which leaves unclear what (c), (d), and (t) are. How about
"GMFN from another dom, XENMEM_add_to_physmap_batch (and
currently ARM) only. Other than XENMAPSPACE_gmfn_foreign this
<explain here what the difference is with a few simple words>."
(You can and should go into further detail in the commit message.)
Without this _properly_ explained, I'll continue to ask why you
can't simply make XENMAPSPACE_gmfn_foreign do what you want
(as it already takes two domid_t-s as input), by suitably adjusting
its XSM check(s).
You'd also need to adjust the comment on the foreign_domid
structure field, as it saying "gmfn_foreign" would otherwise become
stale with your change.
I don't, btw, like the ARM only part here - there's nothing
inherently wrong with the same operation being sensible on x86.
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