Merge tag 'kvm-s390-master-4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux

KVM: s390: Fixes for 4.19

- Fallout from the hugetlbfs support: pfmf interpretion and locking
- VSIE: fix keywrapping for nested guests

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 1b9951d2067e..d668682f91df 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -316,6 +316,14 @@ static bool nvme_dbbuf_update_and_check_event(u16 value, u32 *dbbuf_db,
 		old_value = *dbbuf_db;
 		*dbbuf_db = value;
 
+		/*
+		 * Ensure that the doorbell is updated before reading the event
+		 * index from memory.  The controller needs to provide similar
+		 * ordering to ensure the envent index is updated before reading
+		 * the doorbell.
+		 */
+		mb();
+
 		if (!nvme_dbbuf_need_event(*dbbuf_ei, value, old_value))
 			return false;
 	}