On 22.10.19 11:24, Michal Hocko wrote:
On Tue 22-10-19 11:17:24, David Hildenbrand wrote:
On 22.10.19 11:14, Michal Hocko wrote:
On Tue 22-10-19 10:32:11, David Hildenbrand wrote:
[...]
E.g., arch/x86/kvm/mmu.c:kvm_is_mmio_pfn()
Thanks for these references. I am not really familiar with kvm so I
cannot really comment on the specific code but I am wondering why
it simply doesn't check for ZONE_DEVICE explicitly? Also we do care
about holes in RAM (from the early boot), those should be reserved
already AFAIR. So we are left with hotplugged memory with holes and
I am not really sure we should bother with this until there is a clear
usecase in sight.
Well, checking for ZONE_DEVICE is only possible if you have an initialized
memmap. And that is not guaranteed when you start mapping random stuff into
your guest via /dev/mem.
Yes, I can understand that part but checking PageReserved on an
uninitialized memmap is pointless as well. So if you can test for it you
That's why I add pfn_to_online_page() :)
can very well test for ZONE_DEVICE as well. PageReserved -> ZONE_DEVICE
is a terrible assumption.
Indeed, it is. But there are more parts in the kernel that I'll be
fixing. Stay tuned.
--
Thanks,
David / dhildenb
