Merge feature/hvlite_virtio_pmem/5.10 (8ed0239)

* msft/feature/hvlite_virtio_pmem/5.10:
  virtio-pmem: Set DRIVER_OK status prior to creating pmem region
  virtio-pmem: Support PCI BAR-relative addresses

Author: tyhicks

drivers/nvdimm/virtio_pmem.c

@@ -37,6 +37,8 @@ static int virtio_pmem_probe(struct virtio_device *vdev)
 	struct virtio_pmem *vpmem;
 	struct resource res;
 	int err = 0;
+	bool have_shm_region;
+	struct virtio_shm_region pmem_region;
 
 	if (!vdev->config->get) {
 		dev_err(&vdev->dev, "%s failure: config access disabled\n",
@@ -58,10 +60,21 @@ static int virtio_pmem_probe(struct virtio_device *vdev)
 		goto out_err;
 	}
 
-	virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
-			start, &vpmem->start);
-	virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
-			size, &vpmem->size);
+	/* Retrieve the pmem device's address and size. It may have been supplied
+	 * as a PCI BAR-relative shared memory region, or as a guest absolute address.
+	 */
+	have_shm_region = virtio_get_shm_region(vpmem->vdev, &pmem_region,
+						VIRTIO_PMEM_SHMCAP_ID_PMEM_REGION);
+
+	if (have_shm_region) {
+		vpmem->start = pmem_region.addr;
+		vpmem->size = pmem_region.len;
+	} else {
+		virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
+				start, &vpmem->start);
+		virtio_cread_le(vpmem->vdev, struct virtio_pmem_config,
+				size, &vpmem->size);
+	}
 
 	res.start = vpmem->start;
 	res.end   = vpmem->start + vpmem->size - 1;
@@ -78,6 +91,11 @@ static int virtio_pmem_probe(struct virtio_device *vdev)
 
 	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
 
+	/* Online the device prior to creating a pmem region, to ensure that
+	 * the region is never touched while the device is offline.
+	 */
+	virtio_device_ready(vdev);
+
 	ndr_desc.res = &res;
 	ndr_desc.numa_node = nid;
 	ndr_desc.flush = async_pmem_flush;
@@ -92,6 +110,7 @@ static int virtio_pmem_probe(struct virtio_device *vdev)
 	nd_region->provider_data = dev_to_virtio(nd_region->dev.parent->parent);
 	return 0;
 out_nd:
+	vdev->config->reset(vdev);
 	nvdimm_bus_unregister(vpmem->nvdimm_bus);
 out_vq:
 	vdev->config->del_vqs(vdev);

drivers/nvdimm/virtio_pmem.h

@@ -50,6 +50,9 @@ struct virtio_pmem {
 	__u64 size;
 };
 
+/* For the id field in virtio_pci_shm_cap */
+#define VIRTIO_PMEM_SHMCAP_ID_PMEM_REGION 0
+
 void virtio_pmem_host_ack(struct virtqueue *vq);
 int async_pmem_flush(struct nd_region *nd_region, struct bio *bio);
 #endif