diff options
Diffstat (limited to 'accel')
| -rw-r--r-- | accel/kvm/kvm-all.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 136c8eaed3..7c8ce18bdd 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -728,7 +728,23 @@ static bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn) static void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn) { - gfn->flags = KVM_DIRTY_GFN_F_RESET; + /* + * Use a store-release so that the CPU that executes KVM_RESET_DIRTY_RINGS + * sees the full content of the ring: + * + * CPU0 CPU1 CPU2 + * ------------------------------------------------------------------------------ + * fill gfn0 + * store-rel flags for gfn0 + * load-acq flags for gfn0 + * store-rel RESET for gfn0 + * ioctl(RESET_RINGS) + * load-acq flags for gfn0 + * check if flags have RESET + * + * The synchronization goes from CPU2 to CPU0 to CPU1. + */ + qatomic_store_release(&gfn->flags, KVM_DIRTY_GFN_F_RESET); } /* |