diff options
| -rw-r--r-- | drivers/hv/mshv_eventfd.c | 9 | ||||
| -rw-r--r-- | drivers/hv/mshv_root_main.c | 8 |
2 files changed, 15 insertions, 2 deletions
diff --git a/drivers/hv/mshv_eventfd.c b/drivers/hv/mshv_eventfd.c index 047e5bd43238..06aef99c8298 100644 --- a/drivers/hv/mshv_eventfd.c +++ b/drivers/hv/mshv_eventfd.c @@ -169,7 +169,14 @@ static int mshv_try_assert_irq_fast(struct mshv_irqfd *irqfd) return -EOPNOTSUPP; #endif - vp = partition->pt_vp_array[irq->lapic_apic_id]; + /* + * Pairs with smp_store_release() in mshv_partition_ioctl_create_vp(). + * MSHV_IRQFD does not require the target lapic_apic_id to refer to an + * existing VP, so this read can race a concurrent VP creation; the + * acquire ensures that a non-NULL pointer implies the VP's + * initialising stores are visible. + */ + vp = smp_load_acquire(&partition->pt_vp_array[irq->lapic_apic_id]); if (!vp->vp_register_page) return -EOPNOTSUPP; diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c index 644f9b10cbba..8a15448e2ace 100644 --- a/drivers/hv/mshv_root_main.c +++ b/drivers/hv/mshv_root_main.c @@ -1157,7 +1157,13 @@ mshv_partition_ioctl_create_vp(struct mshv_partition *partition, /* already exclusive with the partition mutex for all ioctls */ partition->pt_vp_count++; - partition->pt_vp_array[args.vp_index] = vp; + /* + * Pairs with smp_load_acquire() in mshv_try_assert_irq_fast(), which + * can run concurrently from an irqfd waker without holding pt_mutex. + * The release ensures the VP's initialising stores are visible to any + * reader that observes a non-NULL pointer in pt_vp_array. + */ + smp_store_release(&partition->pt_vp_array[args.vp_index], vp); goto out; |