diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
index a8d8d1b99647..6dba83708df4 100644
--- a/sys/dev/nvme/nvme_ctrlr.c
+++ b/sys/dev/nvme/nvme_ctrlr.c
@@ -1405,9 +1405,12 @@ nvme_ctrlr_shared_handler(void *arg)
 {
 	struct nvme_controller *ctrlr = arg;
 
-	nvme_mmio_write_4(ctrlr, intms, 1);
+	/* INTMS/INTMC are undefined when configured for MSI-X. */
+	if (!ctrlr->is_msix)
+		nvme_mmio_write_4(ctrlr, intms, 1);
 	nvme_ctrlr_poll(ctrlr);
-	nvme_mmio_write_4(ctrlr, intmc, 1);
+	if (!ctrlr->is_msix)
+		nvme_mmio_write_4(ctrlr, intmc, 1);
 }
 
 #define NVME_MAX_PAGES  (int)(1024 / sizeof(vm_page_t))
diff --git a/sys/dev/nvme/nvme_pci.c b/sys/dev/nvme/nvme_pci.c
index 8ea31850d09b..5d4fab3b2ab1 100644
--- a/sys/dev/nvme/nvme_pci.c
+++ b/sys/dev/nvme/nvme_pci.c
@@ -385,6 +385,7 @@ again:
 		ctrlr->msi_count = 0;
 		goto msi;
 	}
+	ctrlr->is_msix = true;
 	if (ctrlr->msi_count == 1)
 		return (nvme_ctrlr_setup_shared(ctrlr, 1));
 	if (ctrlr->msi_count != num_vectors_requested) {
diff --git a/sys/dev/nvme/nvme_private.h b/sys/dev/nvme/nvme_private.h
index f96729608ed5..9bee1b23bd4e 100644
--- a/sys/dev/nvme/nvme_private.h
+++ b/sys/dev/nvme/nvme_private.h
@@ -257,6 +257,7 @@ struct nvme_controller {
 	struct resource		*msix_pba_resource;
 
 	int			msi_count;
+	bool			is_msix;
 	uint32_t		enable_aborts;
 
 	uint32_t		num_io_queues;