Re: [Xen-devel] [PATCH for-4.12 v2 2/7] amd/npt/shadow: replace assert that prevents creating 2M/1G MMIO entries

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.02.19 at 14:59, <roger.pau@xxxxxxxxxx> wrote:
> On Wed, Feb 13, 2019 at 08:53:14AM -0700, Jan Beulich wrote:
>> >>> On 11.02.19 at 18:46, <roger.pau@xxxxxxxxxx> wrote:
>> > The assert was originally added to make sure that higher order
>> > regions (> PAGE_ORDER_4K) could not be used to bypass the
>> > mmio_ro_ranges check performed by p2m_type_to_flags.
>> > 
>> > This however is already checked in set_mmio_p2m_entry, which makes
>> > sure that higher order mappings don't overlap with mmio_ro_ranges,
>> > thus allowing the creation of high order MMIO mappings safely.
>> > 
>> > Replace the assert to allow 2M/1G entries to be created for MMIO
>> > regions and add some extra asserts as a replacement to make sure
>> > there's no overlapping with MMIO read-only ranges.
>> > 
>> > Note that 1G MMIO entries will not be created unless mmio_order is
>> > changed to allow it.
>> > 
>> > Suggested-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>> 
>> Is this still the case? Iirc the original suggestion was to remove
>> the assertion altogether?
> 
> Right, should I instead add your suggested-by tag?

Or simply leave it out?

Jan



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