vdpa_sim: add struct vdpasim_dev_attr for device attributes

vdpasim_dev_attr will contain device specific attributes. We starting
moving the number of virtqueues (i.e. nvqs) to vdpasim_dev_attr.

vdpasim_create() creates a new vDPA simulator following the device
attributes defined in the vdpasim_dev_attr parameter.

Co-developed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20201215144256.155342-7-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/vdpa_sim/vdpa_sim.c

@@ -65,11 +65,16 @@ static u64 vdpasim_features = (1ULL << VIRTIO_F_ANY_LAYOUT) |
 			      (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
 			      (1ULL << VIRTIO_NET_F_MAC);
 
+struct vdpasim_dev_attr {
+	int nvqs;
+};
+
 /* State of each vdpasim device */
 struct vdpasim {
 	struct vdpa_device vdpa;
 	struct vdpasim_virtqueue *vqs;
 	struct work_struct work;
+	struct vdpasim_dev_attr dev_attr;
 	/* spinlock to synchronize virtqueue state */
 	spinlock_t lock;
 	struct virtio_net_config config;
@@ -78,7 +83,6 @@ struct vdpasim {
 	u32 status;
 	u32 generation;
 	u64 features;
-	int nvqs;
 	/* spinlock to synchronize iommu table */
 	spinlock_t iommu_lock;
 };
@@ -143,7 +147,7 @@ static void vdpasim_reset(struct vdpasim *vdpasim)
 {
 	int i;
 
-	for (i = 0; i < vdpasim->nvqs; i++)
+	for (i = 0; i < vdpasim->dev_attr.nvqs; i++)
 		vdpasim_vq_reset(&vdpasim->vqs[i]);
 
 	spin_lock(&vdpasim->iommu_lock);
@@ -344,7 +348,7 @@ static const struct dma_map_ops vdpasim_dma_ops = {
 static const struct vdpa_config_ops vdpasim_config_ops;
 static const struct vdpa_config_ops vdpasim_batch_config_ops;
 
-static struct vdpasim *vdpasim_create(void)
+static struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
 {
 	const struct vdpa_config_ops *ops;
 	struct vdpasim *vdpasim;
@@ -356,11 +360,12 @@ static struct vdpasim *vdpasim_create(void)
 	else
 		ops = &vdpasim_config_ops;
 
-	vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops, VDPASIM_VQ_NUM);
+	vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
+				    dev_attr->nvqs);
 	if (!vdpasim)
 		goto err_alloc;
 
-	vdpasim->nvqs = VDPASIM_VQ_NUM;
+	vdpasim->dev_attr = *dev_attr;
 	INIT_WORK(&vdpasim->work, vdpasim_work);
 	spin_lock_init(&vdpasim->lock);
 	spin_lock_init(&vdpasim->iommu_lock);
@@ -371,7 +376,7 @@ static struct vdpasim *vdpasim_create(void)
 		goto err_iommu;
 	set_dma_ops(dev, &vdpasim_dma_ops);
 
-	vdpasim->vqs = kcalloc(vdpasim->nvqs, sizeof(struct vdpasim_virtqueue),
+	vdpasim->vqs = kcalloc(dev_attr->nvqs, sizeof(struct vdpasim_virtqueue),
 			       GFP_KERNEL);
 	if (!vdpasim->vqs)
 		goto err_iommu;
@@ -394,7 +399,7 @@ static struct vdpasim *vdpasim_create(void)
 		eth_random_addr(vdpasim->config.mac);
 	}
 
-	for (i = 0; i < vdpasim->nvqs; i++)
+	for (i = 0; i < dev_attr->nvqs; i++)
 		vringh_set_iotlb(&vdpasim->vqs[i].vring, vdpasim->iommu);
 
 	vdpasim->vdpa.dma_dev = dev;
@@ -722,7 +727,11 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
 
 static int __init vdpasim_dev_init(void)
 {
-	vdpasim_dev = vdpasim_create();
+	struct vdpasim_dev_attr dev_attr = {};
+
+	dev_attr.nvqs = VDPASIM_VQ_NUM;
+
+	vdpasim_dev = vdpasim_create(&dev_attr);
 
 	if (!IS_ERR(vdpasim_dev))
 		return 0;