linux/virt/kvm
Andrea Arcangeli 8ee53820ed thp: mmu_notifier_test_young
For GRU and EPT, we need gup-fast to set referenced bit too (this is why
it's correct to return 0 when shadow_access_mask is zero, it requires
gup-fast to set the referenced bit).  qemu-kvm access already sets the
young bit in the pte if it isn't zero-copy, if it's zero copy or a shadow
paging EPT minor fault we relay on gup-fast to signal the page is in
use...

We also need to check the young bits on the secondary pagetables for NPT
and not nested shadow mmu as the data may never get accessed again by the
primary pte.

Without this closer accuracy, we'd have to remove the heuristic that
avoids collapsing hugepages in hugepage virtual regions that have not even
a single subpage in use.

->test_young is full backwards compatible with GRU and other usages that
don't have young bits in pagetables set by the hardware and that should
nuke the secondary mmu mappings when ->clear_flush_young runs just like
EPT does.

Removing the heuristic that checks the young bit in
khugepaged/collapse_huge_page completely isn't so bad either probably but
I thought it was worth it and this makes it reliable.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:46 -08:00
..
assigned-dev.c KVM: Clean up kvm_vm_ioctl_assigned_device 2011-01-12 11:29:24 +02:00
async_pf.c KVM: fix the race while wakeup all pv guest 2011-01-12 11:29:03 +02:00
async_pf.h KVM: Halt vcpu if page it tries to access is swapped out 2011-01-12 11:21:39 +02:00
coalesced_mmio.c KVM: Update Red Hat copyrights 2010-08-01 10:35:51 +03:00
coalesced_mmio.h KVM: Simplify coalesced mmio initialization 2010-03-01 12:35:41 -03:00
eventfd.c KVM: fast-path msi injection with irqfd 2011-01-12 11:29:38 +02:00
ioapic.c KVM: Convert mask notifiers to use irqchip/pin instead of gsi 2010-08-02 06:40:39 +03:00
ioapic.h KVM: convert ioapic lock to spinlock 2010-05-13 01:23:55 -03:00
iodev.h KVM: remove in_range from io devices 2009-09-10 08:33:05 +03:00
iommu.c KVM: Use u64 for frame data types 2010-08-02 06:39:44 +03:00
irq_comm.c KVM: fast-path msi injection with irqfd 2011-01-12 11:29:38 +02:00
Kconfig KVM: Halt vcpu if page it tries to access is swapped out 2011-01-12 11:21:39 +02:00
kvm_main.c thp: mmu_notifier_test_young 2011-01-13 17:32:46 -08:00