tree 4fe27e8dd1a3935757b319726a8b8bdc10496930
parent 342d3db763f2621ed4546ebf8f6c61cb29d7fbdb
author Paul Mackerras <paulus@samba.org> 1323693441 +0000
committer Avi Kivity <avi@redhat.com> 1330951958 +0200

KVM: Add barriers to allow mmu_notifier_retry to be used locklessly

This adds an smp_wmb in kvm_mmu_notifier_invalidate_range_end() and an
smp_rmb in mmu_notifier_retry() so that mmu_notifier_retry() will give
the correct answer when called without kvm->mmu_lock being held.
PowerPC Book3S HV KVM wants to use a bitlock per guest page rather than
a single global spinlock in order to improve the scalability of updates
to the guest MMU hashed page table, and so needs this.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>