Paul Mackerras 11362b1bef KVM: PPC: Book3S HV: Close race with page faults around memslot flushes
There is a potential race condition between hypervisor page faults
and flushing a memslot.  It is possible for a page fault to read the
memslot before a memslot is updated and then write a PTE to the
partition-scoped page tables after kvmppc_radix_flush_memslot has
completed.  (Note that this race has never been explicitly observed.)

To close this race, it is sufficient to increment the MMU sequence
number while the kvm->mmu_lock is held.  That will cause
mmu_notifier_retry() to return true, and the page fault will then
return to the guest without inserting a PTE.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2020-05-28 10:56:42 +10:00
..
2020-03-19 16:39:52 +11:00
2020-03-19 16:39:52 +11:00
2020-04-01 12:06:26 -04:00