Re: [Xen-devel] [PATCH 5 of 9] x86/mm: Ensure maps used by nested hvm code cannot be paged out

["Andres Lagar-Cavilla" <andres@xxxxxxxxxxxxxxxx>]

> At 10:10 +0000 on 30 Nov (1322647821), Jan Beulich wrote:
>>  >>> On 29.11.11 at 21:21, Andres Lagar-Cavilla
>> <andres@xxxxxxxxxxxxxxxx> wrote:
>> > --- a/xen/arch/x86/hvm/hvm.c
>> > +++ b/xen/arch/x86/hvm/hvm.c
>> > @@ -1828,7 +1831,12 @@ static void *__hvm_map_guest_frame(unsig
>> >      if ( writable )
>> >          paging_mark_dirty(d, mfn);
>> >
>> > -    return map_domain_page(mfn);
>> > +    pg = mfn_to_page(mfn);
>> > +    page_get_owner_and_reference(pg);
>>
>> This can (at least theoretically) fail, and you must handle failure (or
>> explain in a comment why not).
>
> Also, you should probably be using get_page(pg, d); is there any
> reason to skip the ownership check?

Shared pages, owner could be dom_cow. Could conditionally get_page if
writable, page_get_owner_and_ref if non writable.

Andres
>
> Tim.
>



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