Re: [PATCH V1 13/16] xen/ioreq: Make x86's invalidate qemu mapcache handling common

[Julien Grall <julien@xxxxxxx>]

Hi Oleksandr,

On 02/10/2020 10:55, Oleksandr wrote:
> If I got it correctly there won't be a suitable common place where to 
> set qemu_mapcache_invalidate flag anymore
> as XENMEM_decrease_reservation is not a single place we need to make a 
> decision whether to set it
> By principle of analogy, on Arm we probably want to do so in 
> guest_physmap_remove_page (or maybe better in p2m_remove_mapping).
> Julien, what do you think?
At the moment, the Arm code doesn't explicitely remove the existing 
mapping before inserting the new mapping. Instead, this is done 
implicitely by p2m_set_entry().
So I think we want to invalidate the QEMU mapcache in p2m_set_entry() if 
the old entry is a RAM page *and* the new MFN is different.
Cheers,

--
Julien Grall