Re: [Xen-devel] [PATCH] vunmap: let vunmap align virtual address by itself

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

On 19.07.19 12:37, Jan Beulich wrote:
> On 18.07.2019 19:11, Andrii Anisov wrote:
> > Let vunmap align passed virtual address by PAGE_SIZE.
> Despite seeing Andrew's R-b you've already got I'd like to point out
> that this increases the risk of some code passing the wrong pointer
> into here. {,un}map_domain_page() act on single pages only, so there's
> no ambiguity. When talking about multi-page regions though, not undoing
> arithmetic previously done may mean actually pointing at other than the
> first page of the mapping.
Well, what we are moving into vunmap(), is a page alignment only. It can't save 
us from the wrong pointer, even if it is done outside the vunmap().

> > With the main change, also:
> >    - strip all existing vunmap() calls from prior masking
> _If_ we are to go this route, then unmap_domain_page_global()
> callers should also be adjusted. There, as for unmap_domain_page(),
> I agree it would make sense to be more tolerant.
I've found two page alignments prior to `unmap_domain_page_global()` call. 
Should I wipe them in this patch, or in separate?

--
Sincerely,
Andrii Anisov.

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