vdpasim: customize allocation size

Allow individual simulator to customize the allocation size.
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221223055548.27810-3-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/vdpa_sim/vdpa_sim.c

@@ -256,6 +256,9 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
 	struct device *dev;
 	int i, ret = -ENOMEM;
 
+	if (!dev_attr->alloc_size)
+		return ERR_PTR(-EINVAL);
+
 	if (config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
 		if (config->device_features &
 		    ~dev_attr->supported_features)
@@ -271,7 +274,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
 
 	vdpa = __vdpa_alloc_device(NULL, ops,
 				   dev_attr->ngroups, dev_attr->nas,
-				   sizeof(struct vdpasim),
+				   dev_attr->alloc_size,
 				   dev_attr->name, false);
 	if (IS_ERR(vdpa)) {
 		ret = PTR_ERR(vdpa);

drivers/vdpa/vdpa_sim/vdpa_sim.h

@@ -37,6 +37,7 @@ struct vdpasim_dev_attr {
 	struct vdpa_mgmt_dev *mgmt_dev;
 	const char *name;
 	u64 supported_features;
+	size_t alloc_size;
 	size_t config_size;
 	size_t buffer_size;
 	int nvqs;

drivers/vdpa/vdpa_sim/vdpa_sim_blk.c

@@ -378,6 +378,7 @@ static int vdpasim_blk_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	dev_attr.nvqs = VDPASIM_BLK_VQ_NUM;
 	dev_attr.ngroups = VDPASIM_BLK_GROUP_NUM;
 	dev_attr.nas = VDPASIM_BLK_AS_NUM;
+	dev_attr.alloc_size = sizeof(struct vdpasim);
 	dev_attr.config_size = sizeof(struct virtio_blk_config);
 	dev_attr.get_config = vdpasim_blk_get_config;
 	dev_attr.work_fn = vdpasim_blk_work;

drivers/vdpa/vdpa_sim/vdpa_sim_net.c

@@ -253,6 +253,7 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
 	dev_attr.ngroups = VDPASIM_NET_GROUP_NUM;
 	dev_attr.nas = VDPASIM_NET_AS_NUM;
+	dev_attr.alloc_size = sizeof(struct vdpasim);
 	dev_attr.config_size = sizeof(struct virtio_net_config);
 	dev_attr.get_config = vdpasim_net_get_config;
 	dev_attr.work_fn = vdpasim_net_work;