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authorLinus Torvalds <torvalds@linux-foundation.org>2021-09-11 14:48:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-11 14:48:42 -0700
commit78e709522d2c012cb0daad2e668506637bffb7c2 (patch)
tree899d892238891f4f2ca1dee3657cb69694c0ca34 /Documentation
parentb79bd0d5102b4a3ea908018fda6b84a4c8fd6235 (diff)
parent7bc7f61897b66bef78bb5952e3d1e9f3aaf9ccca (diff)
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio updates from Michael Tsirkin: - vduse driver ("vDPA Device in Userspace") supporting emulated virtio block devices - virtio-vsock support for end of record with SEQPACKET - vdpa: mac and mq support for ifcvf and mlx5 - vdpa: management netlink for ifcvf - virtio-i2c, gpio dt bindings - misc fixes and cleanups * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (39 commits) Documentation: Add documentation for VDUSE vduse: Introduce VDUSE - vDPA Device in Userspace vduse: Implement an MMU-based software IOTLB vdpa: Support transferring virtual addressing during DMA mapping vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap() vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() vhost-iotlb: Add an opaque pointer for vhost IOTLB vhost-vdpa: Handle the failure of vdpa_reset() vdpa: Add reset callback in vdpa_config_ops vdpa: Fix some coding style issues file: Export receive_fd() to modules eventfd: Export eventfd_wake_count to modules iova: Export alloc_iova_fast() and free_iova_fast() virtio-blk: remove unneeded "likely" statements virtio-balloon: Use virtio_find_vqs() helper vdpa: Make use of PFN_PHYS/PFN_UP/PFN_DOWN helper macro vsock_test: update message bounds test for MSG_EOR af_vsock: rename variables in receive loop virtio/vsock: support MSG_EOR bit processing vhost/vsock: support MSG_EOR bit processing ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/gpio/gpio-virtio.yaml59
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-virtio.yaml51
-rw-r--r--Documentation/devicetree/bindings/virtio/mmio.yaml3
-rw-r--r--Documentation/devicetree/bindings/virtio/virtio-device.yaml41
-rw-r--r--Documentation/userspace-api/index.rst1
-rw-r--r--Documentation/userspace-api/ioctl/ioctl-number.rst1
-rw-r--r--Documentation/userspace-api/vduse.rst233
7 files changed, 388 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
new file mode 100644
index 000000000000..601d85754577
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/gpio-virtio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtio GPIO controller
+
+maintainers:
+ - Viresh Kumar <viresh.kumar@linaro.org>
+
+allOf:
+ - $ref: /schemas/virtio/virtio-device.yaml#
+
+description:
+ Virtio GPIO controller, see /schemas/virtio/virtio-device.yaml for more
+ details.
+
+properties:
+ $nodename:
+ const: gpio
+
+ compatible:
+ const: virtio,device29
+
+ gpio-controller: true
+
+ "#gpio-cells":
+ const: 2
+
+ interrupt-controller: true
+
+ "#interrupt-cells":
+ const: 2
+
+required:
+ - compatible
+ - gpio-controller
+ - "#gpio-cells"
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ virtio@3000 {
+ compatible = "virtio,mmio";
+ reg = <0x3000 0x100>;
+ interrupts = <41>;
+
+ gpio {
+ compatible = "virtio,device29";
+ gpio-controller;
+ #gpio-cells = <2>;
+ interrupt-controller;
+ #interrupt-cells = <2>;
+ };
+ };
+
+...
diff --git a/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml b/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
new file mode 100644
index 000000000000..7d87ed855301
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/i2c-virtio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtio I2C Adapter
+
+maintainers:
+ - Viresh Kumar <viresh.kumar@linaro.org>
+
+allOf:
+ - $ref: /schemas/i2c/i2c-controller.yaml#
+ - $ref: /schemas/virtio/virtio-device.yaml#
+
+description:
+ Virtio I2C device, see /schemas/virtio/virtio-device.yaml for more details.
+
+properties:
+ $nodename:
+ const: i2c
+
+ compatible:
+ const: virtio,device22
+
+required:
+ - compatible
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ virtio@3000 {
+ compatible = "virtio,mmio";
+ reg = <0x3000 0x100>;
+ interrupts = <41>;
+
+ i2c {
+ compatible = "virtio,device22";
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ light-sensor@20 {
+ compatible = "dynaimage,al3320a";
+ reg = <0x20>;
+ };
+ };
+ };
+
+...
diff --git a/Documentation/devicetree/bindings/virtio/mmio.yaml b/Documentation/devicetree/bindings/virtio/mmio.yaml
index d46597028cf1..4b7a0273181c 100644
--- a/Documentation/devicetree/bindings/virtio/mmio.yaml
+++ b/Documentation/devicetree/bindings/virtio/mmio.yaml
@@ -36,7 +36,8 @@ required:
- reg
- interrupts
-additionalProperties: false
+additionalProperties:
+ type: object
examples:
- |
diff --git a/Documentation/devicetree/bindings/virtio/virtio-device.yaml b/Documentation/devicetree/bindings/virtio/virtio-device.yaml
new file mode 100644
index 000000000000..1778ea9b5aa5
--- /dev/null
+++ b/Documentation/devicetree/bindings/virtio/virtio-device.yaml
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/virtio/virtio-device.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtio device bindings
+
+maintainers:
+ - Viresh Kumar <viresh.kumar@linaro.org>
+
+description:
+ These bindings are applicable to virtio devices irrespective of the bus they
+ are bound to, like mmio or pci.
+
+# We need a select here so we don't match all nodes with 'virtio,mmio'
+properties:
+ compatible:
+ pattern: "^virtio,device[0-9a-f]{1,8}$"
+ description: Virtio device nodes.
+ "virtio,deviceID", where ID is the virtio device id. The textual
+ representation of ID shall be in lower case hexadecimal with leading
+ zeroes suppressed.
+
+required:
+ - compatible
+
+additionalProperties: true
+
+examples:
+ - |
+ virtio@3000 {
+ compatible = "virtio,mmio";
+ reg = <0x3000 0x100>;
+ interrupts = <43>;
+
+ i2c {
+ compatible = "virtio,device22";
+ };
+ };
+...
diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index 0b5eefed027e..c432be070f67 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -27,6 +27,7 @@ place where this information is gathered.
iommu
media/index
sysfs-platform_profile
+ vduse
.. only:: subproject and html
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index b7070d76f076..2e8134059c87 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -299,6 +299,7 @@ Code Seq# Include File Comments
'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
'|' 00-7F linux/media.h
0x80 00-1F linux/fb.h
+0x81 00-1F linux/vduse.h
0x89 00-06 arch/x86/include/asm/sockios.h
0x89 0B-DF linux/sockios.h
0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
diff --git a/Documentation/userspace-api/vduse.rst b/Documentation/userspace-api/vduse.rst
new file mode 100644
index 000000000000..42ef59ea5314
--- /dev/null
+++ b/Documentation/userspace-api/vduse.rst
@@ -0,0 +1,233 @@
+==================================
+VDUSE - "vDPA Device in Userspace"
+==================================
+
+vDPA (virtio data path acceleration) device is a device that uses a
+datapath which complies with the virtio specifications with vendor
+specific control path. vDPA devices can be both physically located on
+the hardware or emulated by software. VDUSE is a framework that makes it
+possible to implement software-emulated vDPA devices in userspace. And
+to make the device emulation more secure, the emulated vDPA device's
+control path is handled in the kernel and only the data path is
+implemented in the userspace.
+
+Note that only virtio block device is supported by VDUSE framework now,
+which can reduce security risks when the userspace process that implements
+the data path is run by an unprivileged user. The support for other device
+types can be added after the security issue of corresponding device driver
+is clarified or fixed in the future.
+
+Create/Destroy VDUSE devices
+------------------------
+
+VDUSE devices are created as follows:
+
+1. Create a new VDUSE instance with ioctl(VDUSE_CREATE_DEV) on
+ /dev/vduse/control.
+
+2. Setup each virtqueue with ioctl(VDUSE_VQ_SETUP) on /dev/vduse/$NAME.
+
+3. Begin processing VDUSE messages from /dev/vduse/$NAME. The first
+ messages will arrive while attaching the VDUSE instance to vDPA bus.
+
+4. Send the VDPA_CMD_DEV_NEW netlink message to attach the VDUSE
+ instance to vDPA bus.
+
+VDUSE devices are destroyed as follows:
+
+1. Send the VDPA_CMD_DEV_DEL netlink message to detach the VDUSE
+ instance from vDPA bus.
+
+2. Close the file descriptor referring to /dev/vduse/$NAME.
+
+3. Destroy the VDUSE instance with ioctl(VDUSE_DESTROY_DEV) on
+ /dev/vduse/control.
+
+The netlink messages can be sent via vdpa tool in iproute2 or use the
+below sample codes:
+
+.. code-block:: c
+
+ static int netlink_add_vduse(const char *name, enum vdpa_command cmd)
+ {
+ struct nl_sock *nlsock;
+ struct nl_msg *msg;
+ int famid;
+
+ nlsock = nl_socket_alloc();
+ if (!nlsock)
+ return -ENOMEM;
+
+ if (genl_connect(nlsock))
+ goto free_sock;
+
+ famid = genl_ctrl_resolve(nlsock, VDPA_GENL_NAME);
+ if (famid < 0)
+ goto close_sock;
+
+ msg = nlmsg_alloc();
+ if (!msg)
+ goto close_sock;
+
+ if (!genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, famid, 0, 0, cmd, 0))
+ goto nla_put_failure;
+
+ NLA_PUT_STRING(msg, VDPA_ATTR_DEV_NAME, name);
+ if (cmd == VDPA_CMD_DEV_NEW)
+ NLA_PUT_STRING(msg, VDPA_ATTR_MGMTDEV_DEV_NAME, "vduse");
+
+ if (nl_send_sync(nlsock, msg))
+ goto close_sock;
+
+ nl_close(nlsock);
+ nl_socket_free(nlsock);
+
+ return 0;
+ nla_put_failure:
+ nlmsg_free(msg);
+ close_sock:
+ nl_close(nlsock);
+ free_sock:
+ nl_socket_free(nlsock);
+ return -1;
+ }
+
+How VDUSE works
+---------------
+
+As mentioned above, a VDUSE device is created by ioctl(VDUSE_CREATE_DEV) on
+/dev/vduse/control. With this ioctl, userspace can specify some basic configuration
+such as device name (uniquely identify a VDUSE device), virtio features, virtio
+configuration space, the number of virtqueues and so on for this emulated device.
+Then a char device interface (/dev/vduse/$NAME) is exported to userspace for device
+emulation. Userspace can use the VDUSE_VQ_SETUP ioctl on /dev/vduse/$NAME to
+add per-virtqueue configuration such as the max size of virtqueue to the device.
+
+After the initialization, the VDUSE device can be attached to vDPA bus via
+the VDPA_CMD_DEV_NEW netlink message. Userspace needs to read()/write() on
+/dev/vduse/$NAME to receive/reply some control messages from/to VDUSE kernel
+module as follows:
+
+.. code-block:: c
+
+ static int vduse_message_handler(int dev_fd)
+ {
+ int len;
+ struct vduse_dev_request req;
+ struct vduse_dev_response resp;
+
+ len = read(dev_fd, &req, sizeof(req));
+ if (len != sizeof(req))
+ return -1;
+
+ resp.request_id = req.request_id;
+
+ switch (req.type) {
+
+ /* handle different types of messages */
+
+ }
+
+ len = write(dev_fd, &resp, sizeof(resp));
+ if (len != sizeof(resp))
+ return -1;
+
+ return 0;
+ }
+
+There are now three types of messages introduced by VDUSE framework:
+
+- VDUSE_GET_VQ_STATE: Get the state for virtqueue, userspace should return
+ avail index for split virtqueue or the device/driver ring wrap counters and
+ the avail and used index for packed virtqueue.
+
+- VDUSE_SET_STATUS: Set the device status, userspace should follow
+ the virtio spec: https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.html
+ to process this message. For example, fail to set the FEATURES_OK device
+ status bit if the device can not accept the negotiated virtio features
+ get from the VDUSE_DEV_GET_FEATURES ioctl.
+
+- VDUSE_UPDATE_IOTLB: Notify userspace to update the memory mapping for specified
+ IOVA range, userspace should firstly remove the old mapping, then setup the new
+ mapping via the VDUSE_IOTLB_GET_FD ioctl.
+
+After DRIVER_OK status bit is set via the VDUSE_SET_STATUS message, userspace is
+able to start the dataplane processing as follows:
+
+1. Get the specified virtqueue's information with the VDUSE_VQ_GET_INFO ioctl,
+ including the size, the IOVAs of descriptor table, available ring and used ring,
+ the state and the ready status.
+
+2. Pass the above IOVAs to the VDUSE_IOTLB_GET_FD ioctl so that those IOVA regions
+ can be mapped into userspace. Some sample codes is shown below:
+
+.. code-block:: c
+
+ static int perm_to_prot(uint8_t perm)
+ {
+ int prot = 0;
+
+ switch (perm) {
+ case VDUSE_ACCESS_WO:
+ prot |= PROT_WRITE;
+ break;
+ case VDUSE_ACCESS_RO:
+ prot |= PROT_READ;
+ break;
+ case VDUSE_ACCESS_RW:
+ prot |= PROT_READ | PROT_WRITE;
+ break;
+ }
+
+ return prot;
+ }
+
+ static void *iova_to_va(int dev_fd, uint64_t iova, uint64_t *len)
+ {
+ int fd;
+ void *addr;
+ size_t size;
+ struct vduse_iotlb_entry entry;
+
+ entry.start = iova;
+ entry.last = iova;
+
+ /*
+ * Find the first IOVA region that overlaps with the specified
+ * range [start, last] and return the corresponding file descriptor.
+ */
+ fd = ioctl(dev_fd, VDUSE_IOTLB_GET_FD, &entry);
+ if (fd < 0)
+ return NULL;
+
+ size = entry.last - entry.start + 1;
+ *len = entry.last - iova + 1;
+ addr = mmap(0, size, perm_to_prot(entry.perm), MAP_SHARED,
+ fd, entry.offset);
+ close(fd);
+ if (addr == MAP_FAILED)
+ return NULL;
+
+ /*
+ * Using some data structures such as linked list to store
+ * the iotlb mapping. The munmap(2) should be called for the
+ * cached mapping when the corresponding VDUSE_UPDATE_IOTLB
+ * message is received or the device is reset.
+ */
+
+ return addr + iova - entry.start;
+ }
+
+3. Setup the kick eventfd for the specified virtqueues with the VDUSE_VQ_SETUP_KICKFD
+ ioctl. The kick eventfd is used by VDUSE kernel module to notify userspace to
+ consume the available ring. This is optional since userspace can choose to poll the
+ available ring instead.
+
+4. Listen to the kick eventfd (optional) and consume the available ring. The buffer
+ described by the descriptors in the descriptor table should be also mapped into
+ userspace via the VDUSE_IOTLB_GET_FD ioctl before accessing.
+
+5. Inject an interrupt for specific virtqueue with the VDUSE_INJECT_VQ_IRQ ioctl
+ after the used ring is filled.
+
+For more details on the uAPI, please see include/uapi/linux/vduse.h.