Re: [Xen-devel] [PATCH 3/3] memory: restrict XENMEM_remove_from_physmap to translated guests

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 05.03.19 at 14:53, <jgross@xxxxxxxx> wrote:
> On 05/03/2019 14:28, Jan Beulich wrote:
>> The commit re-introducing it (14eb3b41d0 ["xen: reinstate previously
>> unused XENMEM_remove_from_physmap hypercall"]) as well as the one having
>> originally introduced it (d818f3cb7c ["hvm: Use main memory for video
>> memory"]) and the one then purging it again (78c3097e4f ["Remove unused
>> XENMEM_remove_from_physmap"]) make clear that this operation is intended
>> for use on HVM (i.e. translated) guests only. Restrict it at least as
>> much, because for PV guests documentation (in the public header) does
>> not even match the implementation: It talks about GPFN as input, but
>> get_page_from_gfn() assumes a GMFN in the non-translated case (and hands
>> back the value passed in).
>> 
>> Also lift the check in XENMEM_add_to_physmap{,_batch} handling up
>> directly into top level hypercall handling, and clarify things in the
>> public header accordingly.
>> 
>> Take the liberty and also replace a pointless use of "current" with a
>> more efficient use of an existing local variable (or function parameter
>> to be precise).
>> 
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> Do I read this correctly: nothing bad for the host can happen without
> this patch?

If you add "It is believed that ...", then yes.

> If this is correct I'd like to defer this patch until 4.13.

Okay.

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel