[PATCH vfio 3/7] virtio: Manage device and driver capabilities via the admin commands

[Yishai Hadas <yishaih@nvidia.com>]

Manage device and driver capabilities via the admin commands.

The device exposes its supported features and resource object limits via
an administrative command called VIRTIO_ADMIN_CMD_CAP_ID_LIST_QUERY,
using the 'self group type.'

Each capability is identified by a unique ID, and the driver
communicates the functionality and resource limits it plans to utilize.

The capability VIRTIO_DEV_PARTS_CAP specifically represents the device's
parts resource object limit.

Manage the device's parts resource object ID using a common IDA for both
get and set operations.

Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
---
 drivers/virtio/virtio_pci_common.h |  13 +++-
 drivers/virtio/virtio_pci_modern.c | 105 +++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
index 1d9c49947f52..04b1d17663b3 100644
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -48,6 +48,9 @@ struct virtio_pci_admin_vq {
 	/* Protects virtqueue access. */
 	spinlock_t lock;
 	u64 supported_cmds;
+	u64 supported_caps;
+	u8 max_dev_parts_objects;
+	struct ida dev_parts_ida;
 	/* Name of the admin queue: avq.$vq_index. */
 	char name[10];
 	u16 vq_index;
@@ -167,15 +170,21 @@ struct virtio_device *virtio_pci_vf_get_pf_dev(struct pci_dev *pdev);
 	 BIT_ULL(VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ) | \
 	 BIT_ULL(VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO))
 
+#define VIRTIO_DEV_PARTS_ADMIN_CMD_BITMAP \
+	(BIT_ULL(VIRTIO_ADMIN_CMD_CAP_ID_LIST_QUERY) | \
+	 BIT_ULL(VIRTIO_ADMIN_CMD_DRIVER_CAP_SET) | \
+	 BIT_ULL(VIRTIO_ADMIN_CMD_DEVICE_CAP_GET))
+
 /* Unlike modern drivers which support hardware virtio devices, legacy drivers
  * assume software-based devices: e.g. they don't use proper memory barriers
  * on ARM, use big endian on PPC, etc. X86 drivers are mostly ok though, more
  * or less by chance. For now, only support legacy IO on X86.
  */
 #ifdef CONFIG_VIRTIO_PCI_ADMIN_LEGACY
-#define VIRTIO_ADMIN_CMD_BITMAP VIRTIO_LEGACY_ADMIN_CMD_BITMAP
+#define VIRTIO_ADMIN_CMD_BITMAP (VIRTIO_LEGACY_ADMIN_CMD_BITMAP | \
+				 VIRTIO_DEV_PARTS_ADMIN_CMD_BITMAP)
 #else
-#define VIRTIO_ADMIN_CMD_BITMAP 0
+#define VIRTIO_ADMIN_CMD_BITMAP VIRTIO_DEV_PARTS_ADMIN_CMD_BITMAP
 #endif
 
 void vp_modern_avq_done(struct virtqueue *vq);
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 487d04610ecb..8ddac2829bc8 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -230,12 +230,117 @@ static void virtio_pci_admin_cmd_list_init(struct virtio_device *virtio_dev)
 	kfree(data);
 }
 
+static void
+virtio_pci_admin_cmd_dev_parts_objects_enable(struct virtio_device *virtio_dev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(virtio_dev);
+	struct virtio_admin_cmd_cap_get_data *get_data;
+	struct virtio_admin_cmd_cap_set_data *set_data;
+	struct virtio_dev_parts_cap *result;
+	struct virtio_admin_cmd cmd = {};
+	struct scatterlist result_sg;
+	struct scatterlist data_sg;
+	u8 resource_objects_limit;
+	u16 set_data_size;
+	int ret;
+
+	get_data = kzalloc(sizeof(*get_data), GFP_KERNEL);
+	if (!get_data)
+		return;
+
+	result = kzalloc(sizeof(*result), GFP_KERNEL);
+	if (!result)
+		goto end;
+
+	get_data->id = cpu_to_le16(VIRTIO_DEV_PARTS_CAP);
+	sg_init_one(&data_sg, get_data, sizeof(*get_data));
+	sg_init_one(&result_sg, result, sizeof(*result));
+	cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_DEVICE_CAP_GET);
+	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
+	cmd.data_sg = &data_sg;
+	cmd.result_sg = &result_sg;
+	ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd);
+	if (ret)
+		goto err_get;
+
+	set_data_size = sizeof(*set_data) + sizeof(*result);
+	set_data = kzalloc(set_data_size, GFP_KERNEL);
+	if (!set_data)
+		goto err_get;
+
+	set_data->id = cpu_to_le16(VIRTIO_DEV_PARTS_CAP);
+
+	/* Set the limit to the minimum value between the GET and SET values
+	 * supported by the device. Since the obj_id for VIRTIO_DEV_PARTS_CAP
+	 * is a globally unique value per PF, there is no possibility of
+	 * overlap between GET and SET operations.
+	 */
+	resource_objects_limit = min(result->get_parts_resource_objects_limit,
+				     result->set_parts_resource_objects_limit);
+	result->get_parts_resource_objects_limit = resource_objects_limit;
+	result->set_parts_resource_objects_limit = resource_objects_limit;
+	memcpy(set_data->cap_specific_data, result, sizeof(*result));
+	sg_init_one(&data_sg, set_data, set_data_size);
+	cmd.data_sg = &data_sg;
+	cmd.result_sg = NULL;
+	cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_DRIVER_CAP_SET);
+	ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd);
+	if (ret)
+		goto err_set;
+
+	/* Allocate IDR to manage the dev caps objects */
+	ida_init(&vp_dev->admin_vq.dev_parts_ida);
+	vp_dev->admin_vq.max_dev_parts_objects = resource_objects_limit;
+
+err_set:
+	kfree(set_data);
+err_get:
+	kfree(result);
+end:
+	kfree(get_data);
+}
+
+static void virtio_pci_admin_cmd_cap_init(struct virtio_device *virtio_dev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(virtio_dev);
+	struct virtio_admin_cmd_query_cap_id_result *data;
+	struct virtio_admin_cmd cmd = {};
+	struct scatterlist result_sg;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return;
+
+	sg_init_one(&result_sg, data, sizeof(*data));
+	cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_CAP_ID_LIST_QUERY);
+	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
+	cmd.result_sg = &result_sg;
+
+	ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd);
+	if (ret)
+		goto end;
+
+	/* Max number of caps fits into a single u64 */
+	BUILD_BUG_ON(sizeof(data->supported_caps) > sizeof(u64));
+
+	vp_dev->admin_vq.supported_caps = le64_to_cpu(data->supported_caps[0]);
+
+	if (!(vp_dev->admin_vq.supported_caps & (1 << VIRTIO_DEV_PARTS_CAP)))
+		goto end;
+
+	virtio_pci_admin_cmd_dev_parts_objects_enable(virtio_dev);
+end:
+	kfree(data);
+}
+
 static void vp_modern_avq_activate(struct virtio_device *vdev)
 {
 	if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
 		return;
 
 	virtio_pci_admin_cmd_list_init(vdev);
+	virtio_pci_admin_cmd_cap_init(vdev);
 }
 
 static void vp_modern_avq_cleanup(struct virtio_device *vdev)
-- 
2.27.0