@@ -1440,6 +1440,18 @@ Front-end message types
query the back-end for its device status as defined in the Virtio
specification.
+``VHOST_USER_GET_SHARED_OBJECT``
+ :id: 41
+ :equivalent ioctl: N/A
+ :request payload: ``struct VhostUserShared``
+ :reply payload: dmabuf fd
+
+ When the ``VHOST_USER_PROTOCOL_F_SHARED_OBJECT`` protocol
+ feature has been successfully negotiated, and the UUID is found
+ in the exporters cache, this message is submitted by the front-end
+ to retrieve a given dma-buf fd from a given back-end, determined by
+ the requested UUID. Back-end will reply passing the fd when the operation
+ is successful, or no fd otherwise.
Back-end message types
----------------------
@@ -1528,6 +1540,51 @@ is sent by the front-end.
The state.num field is currently reserved and must be set to 0.
+``VHOST_USER_BACKEND_SHARED_OBJECT_ADD``
+ :id: 6
+ :equivalent ioctl: N/A
+ :request payload: ``struct VhostUserShared``
+ :reply payload: N/A
+
+ When the ``VHOST_USER_PROTOCOL_F_SHARED_OBJECT`` protocol
+ feature has been successfully negotiated, this message can be submitted
+ by the backends to add themselves as exporters to the virtio shared lookup
+ table. The back-end device gets associated with a UUID in the shared table.
+ The back-end is responsible of keeping its own table with exported dma-buf fds.
+ When another back-end tries to import the resource associated with the UUID,
+ it will send a message to the front-end, which will act as a proxy to the
+ exporter back-end. If ``VHOST_USER_PROTOCOL_F_REPLY_ACK`` is negotiated, and
+ the back-end sets the ``VHOST_USER_NEED_REPLY`` flag, the front-end must
+ respond with zero when operation is successfully completed, or non-zero
+ otherwise.
+
+``VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE``
+ :id: 7
+ :equivalent ioctl: N/A
+ :request payload: ``struct VhostUserShared``
+ :reply payload: N/A
+
+ When the ``VHOST_USER_PROTOCOL_F_SHARED_OBJECT`` protocol
+ feature has been successfully negotiated, this message can be submitted
+ by the backend to remove themselves from to the virtio-dmabuf shared
+ table API. The shared table will remove the back-end device associated with
+ the UUID. If ``VHOST_USER_PROTOCOL_F_REPLY_ACK`` is negotiated, and the
+ back-end sets the ``VHOST_USER_NEED_REPLY`` flag, the front-end must respond
+ with zero when operation is successfully completed, or non-zero otherwise.
+
+``VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP``
+ :id: 8
+ :equivalent ioctl: N/A
+ :request payload: ``struct VhostUserShared``
+ :reply payload: dmabuf fd and ``u64``
+
+ When the ``VHOST_USER_PROTOCOL_F_SHARED_OBJECT`` protocol
+ feature has been successfully negotiated, this message can be submitted
+ by the backends to retrieve a given dma-buf fd from the virtio-dmabuf
+ shared table given a UUID. Frontend will reply passing the fd and a zero
+ when the operation is successful, or non-zero otherwise. Note that if the
+ operation fails, no fd is sent to the backend.
+
.. _reply_ack:
VHOST_USER_PROTOCOL_F_REPLY_ACK
@@ -10,6 +10,7 @@
#include "qemu/osdep.h"
#include "qapi/error.h"
+#include "hw/virtio/virtio-dmabuf.h"
#include "hw/virtio/vhost.h"
#include "hw/virtio/virtio-crypto.h"
#include "hw/virtio/vhost-user.h"
@@ -21,6 +22,7 @@
#include "sysemu/kvm.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
+#include "qemu/uuid.h"
#include "qemu/sockets.h"
#include "sysemu/runstate.h"
#include "sysemu/cryptodev.h"
@@ -74,6 +76,7 @@ enum VhostUserProtocolFeature {
/* Feature 14 reserved for VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS. */
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15,
VHOST_USER_PROTOCOL_F_STATUS = 16,
+ VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 17,
VHOST_USER_PROTOCOL_F_MAX
};
@@ -121,6 +124,7 @@ typedef enum VhostUserRequest {
VHOST_USER_REM_MEM_REG = 38,
VHOST_USER_SET_STATUS = 39,
VHOST_USER_GET_STATUS = 40,
+ VHOST_USER_GET_SHARED_OBJECT = 41,
VHOST_USER_MAX
} VhostUserRequest;
@@ -129,6 +133,9 @@ typedef enum VhostUserBackendRequest {
VHOST_USER_BACKEND_IOTLB_MSG = 1,
VHOST_USER_BACKEND_CONFIG_CHANGE_MSG = 2,
VHOST_USER_BACKEND_VRING_HOST_NOTIFIER_MSG = 3,
+ VHOST_USER_BACKEND_SHARED_OBJECT_ADD = 6,
+ VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE = 7,
+ VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP = 8,
VHOST_USER_BACKEND_MAX
} VhostUserBackendRequest;
@@ -202,6 +209,10 @@ typedef struct VhostUserInflight {
uint16_t queue_size;
} VhostUserInflight;
+typedef struct VhostUserShared {
+ unsigned char uuid[16];
+} VhostUserShared;
+
typedef struct {
VhostUserRequest request;
@@ -226,6 +237,7 @@ typedef union {
VhostUserCryptoSession session;
VhostUserVringArea area;
VhostUserInflight inflight;
+ VhostUserShared object;
} VhostUserPayload;
typedef struct VhostUserMsg {
@@ -1601,6 +1613,144 @@ static int vhost_user_backend_handle_vring_host_notifier(struct vhost_dev *dev,
return 0;
}
+static int
+vhost_user_backend_handle_shared_object_add(struct vhost_dev *dev,
+ VhostUserShared *object)
+{
+ QemuUUID uuid;
+
+ memcpy(uuid.data, object->uuid, sizeof(object->uuid));
+ return virtio_add_vhost_device(&uuid, dev);
+}
+
+static int
+vhost_user_backend_handle_shared_object_remove(VhostUserShared *object)
+{
+ QemuUUID uuid;
+
+ memcpy(uuid.data, object->uuid, sizeof(object->uuid));
+ return virtio_remove_resource(&uuid);
+}
+
+static bool vhost_user_send_resp(QIOChannel *ioc, VhostUserHeader *hdr,
+ VhostUserPayload *payload)
+{
+ Error *local_err = NULL;
+ struct iovec iov[] = {
+ { .iov_base = hdr, .iov_len = VHOST_USER_HDR_SIZE },
+ { .iov_base = payload, .iov_len = hdr->size },
+ };
+
+ hdr->flags &= ~VHOST_USER_NEED_REPLY_MASK;
+ hdr->flags |= VHOST_USER_REPLY_MASK;
+
+ if (qio_channel_writev_all(ioc, iov, ARRAY_SIZE(iov), &local_err)) {
+ error_report_err(local_err);
+ return false;
+ }
+
+ return true;
+}
+
+static bool
+vhost_user_backend_send_dmabuf_fd(QIOChannel *ioc, VhostUserHeader *hdr,
+ VhostUserPayload *payload)
+{
+ hdr->size = sizeof(payload->u64);
+ return vhost_user_send_resp(ioc, hdr, payload);
+}
+
+int vhost_user_get_shared_object(struct vhost_dev *dev, unsigned char *uuid,
+ int *dmabuf_fd)
+{
+ struct vhost_user *u = dev->opaque;
+ CharBackend *chr = u->user->chr;
+ int ret;
+ VhostUserMsg msg = {
+ .hdr.request = VHOST_USER_GET_SHARED_OBJECT,
+ .hdr.flags = VHOST_USER_VERSION,
+ };
+ memcpy(msg.payload.object.uuid, uuid, sizeof(msg.payload.object.uuid));
+
+ ret = vhost_user_write(dev, &msg, NULL, 0);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = vhost_user_read(dev, &msg);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (msg.hdr.request != VHOST_USER_GET_SHARED_OBJECT) {
+ error_report("Received unexpected msg type. "
+ "Expected %d received %d",
+ VHOST_USER_GET_SHARED_OBJECT, msg.hdr.request);
+ return -EPROTO;
+ }
+
+ *dmabuf_fd = qemu_chr_fe_get_msgfd(chr);
+ if (*dmabuf_fd < 0) {
+ error_report("Failed to get dmabuf fd");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int
+vhost_user_backend_handle_shared_object_lookup(struct vhost_user *u,
+ QIOChannel *ioc,
+ VhostUserHeader *hdr,
+ VhostUserPayload *payload)
+{
+ QemuUUID uuid;
+ CharBackend *chr = u->user->chr;
+ int dmabuf_fd = -1;
+ int fd_num = 0;
+
+ memcpy(uuid.data, payload->object.uuid, sizeof(payload->object.uuid));
+
+ payload->u64 = 0;
+ switch (virtio_object_type(&uuid)) {
+ case TYPE_DMABUF:
+ dmabuf_fd = virtio_lookup_dmabuf(&uuid);
+ break;
+ case TYPE_VHOST_DEV:
+ {
+ struct vhost_dev *dev = virtio_lookup_vhost_device(&uuid);
+ if (dev == NULL) {
+ payload->u64 = -EINVAL;
+ break;
+ }
+ int ret = vhost_user_get_shared_object(dev, uuid.data, &dmabuf_fd);
+ if (ret < 0) {
+ payload->u64 = ret;
+ }
+ break;
+ }
+ case TYPE_INVALID:
+ payload->u64 = -EINVAL;
+ break;
+ }
+
+ if (dmabuf_fd != -1) {
+ fd_num++;
+ }
+
+ if (qemu_chr_fe_set_msgfds(chr, &dmabuf_fd, fd_num) < 0) {
+ error_report("Failed to set msg fds.");
+ payload->u64 = -EINVAL;
+ }
+
+ if (!vhost_user_backend_send_dmabuf_fd(ioc, hdr, payload)) {
+ error_report("Failed to write response msg.");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static void close_backend_channel(struct vhost_user *u)
{
g_source_destroy(u->backend_src);
@@ -1658,6 +1808,16 @@ static gboolean backend_read(QIOChannel *ioc, GIOCondition condition,
ret = vhost_user_backend_handle_vring_host_notifier(dev, &payload.area,
fd ? fd[0] : -1);
break;
+ case VHOST_USER_BACKEND_SHARED_OBJECT_ADD:
+ ret = vhost_user_backend_handle_shared_object_add(dev, &payload.object);
+ break;
+ case VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE:
+ ret = vhost_user_backend_handle_shared_object_remove(&payload.object);
+ break;
+ case VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP:
+ ret = vhost_user_backend_handle_shared_object_lookup(dev->opaque, ioc,
+ &hdr, &payload);
+ break;
default:
error_report("Received unexpected msg type: %d.", hdr.request);
ret = -EINVAL;
@@ -1668,22 +1828,10 @@ static gboolean backend_read(QIOChannel *ioc, GIOCondition condition,
* directly in their request handlers.
*/
if (hdr.flags & VHOST_USER_NEED_REPLY_MASK) {
- struct iovec iovec[2];
-
-
- hdr.flags &= ~VHOST_USER_NEED_REPLY_MASK;
- hdr.flags |= VHOST_USER_REPLY_MASK;
-
payload.u64 = !!ret;
hdr.size = sizeof(payload.u64);
- iovec[0].iov_base = &hdr;
- iovec[0].iov_len = VHOST_USER_HDR_SIZE;
- iovec[1].iov_base = &payload;
- iovec[1].iov_len = hdr.size;
-
- if (qio_channel_writev_all(ioc, iovec, ARRAY_SIZE(iovec), &local_err)) {
- error_report_err(local_err);
+ if (!vhost_user_send_resp(ioc, &hdr, &payload)) {
goto err;
}
}
@@ -196,4 +196,7 @@ int vhost_backend_handle_iotlb_msg(struct vhost_dev *dev,
int vhost_user_gpu_set_socket(struct vhost_dev *dev, int fd);
+int vhost_user_get_shared_object(struct vhost_dev *dev, unsigned char *uuid,
+ int *dmabuf_fd);
+
#endif /* VHOST_BACKEND_H */
@@ -161,6 +161,7 @@ vu_request_to_string(unsigned int req)
REQ(VHOST_USER_GET_MAX_MEM_SLOTS),
REQ(VHOST_USER_ADD_MEM_REG),
REQ(VHOST_USER_REM_MEM_REG),
+ REQ(VHOST_USER_GET_SHARED_OBJECT),
REQ(VHOST_USER_MAX),
};
#undef REQ
@@ -900,6 +901,23 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
return false;
}
+static bool
+vu_get_shared_object(VuDev *dev, VhostUserMsg *vmsg)
+{
+ int fd_num = 0;
+ int dmabuf_fd = -1;
+ if (dev->iface->get_shared_object) {
+ dmabuf_fd = dev->iface->get_shared_object(dev, &vmsg->payload.object.uuid[0]);
+ }
+ if (dmabuf_fd != -1) {
+ DPRINT("dmabuf_fd found for requested UUID\n");
+ vmsg->fds[fd_num++] = dmabuf_fd;
+ }
+ vmsg->fd_num = fd_num;
+
+ return true;
+}
+
static bool
vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
{
@@ -1403,6 +1421,104 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
return vu_process_message_reply(dev, &vmsg);
}
+bool
+vu_lookup_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN], int *dmabuf_fd)
+{
+ bool result = false;
+ VhostUserMsg msg_reply;
+ VhostUserMsg msg = {
+ .request = VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP,
+ .size = sizeof(msg.payload.object),
+ .flags = VHOST_USER_VERSION | VHOST_USER_NEED_REPLY_MASK,
+ };
+
+ memcpy(msg.payload.object.uuid, uuid, sizeof(uuid[0]) * UUID_LEN);
+
+ if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SHARED_OBJECT)) {
+ return false;
+ }
+
+ pthread_mutex_lock(&dev->backend_mutex);
+ if (!vu_message_write(dev, dev->backend_fd, &msg)) {
+ goto out;
+ }
+
+ if (!vu_message_read_default(dev, dev->backend_fd, &msg_reply)) {
+ goto out;
+ }
+
+ if (msg_reply.request != msg.request) {
+ DPRINT("Received unexpected msg type. Expected %d, received %d",
+ msg.request, msg_reply.request);
+ goto out;
+ }
+
+ if (msg_reply.fd_num != 1) {
+ DPRINT("Received unexpected number of fds. Expected 1, received %d",
+ msg_reply.fd_num);
+ goto out;
+ }
+
+ *dmabuf_fd = msg_reply.fds[0];
+ result = *dmabuf_fd > 0 && msg_reply.payload.u64 == 0;
+out:
+ pthread_mutex_unlock(&dev->backend_mutex);
+
+ return result;
+}
+
+static bool
+vu_send_message(VuDev *dev, VhostUserMsg *vmsg)
+{
+ bool result = false;
+ pthread_mutex_lock(&dev->backend_mutex);
+ if (!vu_message_write(dev, dev->backend_fd, vmsg)) {
+ goto out;
+ }
+
+ result = true;
+out:
+ pthread_mutex_unlock(&dev->backend_mutex);
+
+ return result;
+}
+
+bool
+vu_add_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN])
+{
+ VhostUserMsg msg = {
+ .request = VHOST_USER_BACKEND_SHARED_OBJECT_ADD,
+ .size = sizeof(msg.payload.object),
+ .flags = VHOST_USER_VERSION,
+ };
+
+ memcpy(msg.payload.object.uuid, uuid, sizeof(uuid[0]) * UUID_LEN);
+
+ if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SHARED_OBJECT)) {
+ return false;
+ }
+
+ return vu_send_message(dev, &msg);
+}
+
+bool
+vu_rm_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN])
+{
+ VhostUserMsg msg = {
+ .request = VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE,
+ .size = sizeof(msg.payload.object),
+ .flags = VHOST_USER_VERSION,
+ };
+
+ memcpy(msg.payload.object.uuid, uuid, sizeof(uuid[0]) * UUID_LEN);
+
+ if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SHARED_OBJECT)) {
+ return false;
+ }
+
+ return vu_send_message(dev, &msg);
+}
+
static bool
vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg)
{
@@ -1943,6 +2059,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
return vu_add_mem_reg(dev, vmsg);
case VHOST_USER_REM_MEM_REG:
return vu_rem_mem_reg(dev, vmsg);
+ case VHOST_USER_GET_SHARED_OBJECT:
+ return vu_get_shared_object(dev, vmsg);
default:
vmsg_close_fds(vmsg);
vu_panic(dev, "Unhandled request: %d", vmsg->request);
@@ -64,7 +64,8 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14,
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15,
-
+ /* Feature 16 is reserved for VHOST_USER_PROTOCOL_F_STATUS. */
+ VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 17,
VHOST_USER_PROTOCOL_F_MAX
};
@@ -109,6 +110,7 @@ typedef enum VhostUserRequest {
VHOST_USER_GET_MAX_MEM_SLOTS = 36,
VHOST_USER_ADD_MEM_REG = 37,
VHOST_USER_REM_MEM_REG = 38,
+ VHOST_USER_GET_SHARED_OBJECT = 41,
VHOST_USER_MAX
} VhostUserRequest;
@@ -119,6 +121,9 @@ typedef enum VhostUserBackendRequest {
VHOST_USER_BACKEND_VRING_HOST_NOTIFIER_MSG = 3,
VHOST_USER_BACKEND_VRING_CALL = 4,
VHOST_USER_BACKEND_VRING_ERR = 5,
+ VHOST_USER_BACKEND_SHARED_OBJECT_ADD = 6,
+ VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE = 7,
+ VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP = 8,
VHOST_USER_BACKEND_MAX
} VhostUserBackendRequest;
@@ -172,6 +177,12 @@ typedef struct VhostUserInflight {
uint16_t queue_size;
} VhostUserInflight;
+#define UUID_LEN 16
+
+typedef struct VhostUserShared {
+ unsigned char uuid[UUID_LEN];
+} VhostUserShared;
+
#if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__))
# define VU_PACKED __attribute__((gcc_struct, packed))
#else
@@ -199,6 +210,7 @@ typedef struct VhostUserMsg {
VhostUserConfig config;
VhostUserVringArea area;
VhostUserInflight inflight;
+ VhostUserShared object;
} payload;
int fds[VHOST_MEMORY_BASELINE_NREGIONS];
@@ -232,6 +244,7 @@ typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, uint32_t len);
typedef int (*vu_set_config_cb) (VuDev *dev, const uint8_t *data,
uint32_t offset, uint32_t size,
uint32_t flags);
+typedef int (*vu_get_shared_object_cb) (VuDev *dev, const unsigned char *uuid);
typedef struct VuDevIface {
/* called by VHOST_USER_GET_FEATURES to get the features bitmask */
@@ -258,6 +271,8 @@ typedef struct VuDevIface {
vu_get_config_cb get_config;
/* set the config space of the device */
vu_set_config_cb set_config;
+ /* get virtio shared object from the underlying vhost implementation. */
+ vu_get_shared_object_cb get_shared_object;
} VuDevIface;
typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx);
@@ -541,6 +556,44 @@ void vu_set_queue_handler(VuDev *dev, VuVirtq *vq,
bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
int size, int offset);
+/**
+ * vu_lookup_shared_object:
+ * @dev: a VuDev context
+ * @uuid: UUID of the shared object
+ * @dmabuf_fd: output dma-buf file descriptor
+ *
+ * Lookup for a virtio shared object (i.e., dma-buf fd) associated with the
+ * received UUID. Result, if found, is stored in the dmabuf_fd argument.
+ *
+ * Returns: whether the virtio object was found.
+ */
+bool vu_lookup_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN],
+ int *dmabuf_fd);
+
+/**
+ * vu_add_shared_object:
+ * @dev: a VuDev context
+ * @uuid: UUID of the shared object
+ *
+ * Registers this back-end as the exporter for the object associated with
+ * the received UUID.
+ *
+ * Returns: TRUE on success, FALSE on failure.
+ */
+bool vu_add_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN]);
+
+/**
+ * vu_rm_shared_object:
+ * @dev: a VuDev context
+ * @uuid: UUID of the shared object
+ *
+ * Removes a shared object entry (i.e., back-end entry) associated with the
+ * received UUID key from the hash table.
+ *
+ * Returns: TRUE on success, FALSE on failure.
+ */
+bool vu_rm_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN]);
+
/**
* vu_queue_set_notification:
* @dev: a VuDev context
Add three new vhost-user protocol `VHOST_USER_BACKEND_SHARED_OBJECT_* messages`. These new messages are sent from vhost-user back-ends to interact with the virtio-dmabuf table in order to add or remove themselves as virtio exporters, or lookup for virtio dma-buf shared objects. The action taken in the front-end depends on the type stored in the virtio shared object hash table. When the table holds a pointer to a vhost backend for a given UUID, the front-end sends a VHOST_USER_GET_SHARED_OBJECT to the backend holding the shared object. In the libvhost-user library we need to add helper functions to allow sending messages to interact with the virtio shared objects hash table. The messages can only be sent after successfully negotiating a new VHOST_USER_PROTOCOL_F_SHARED_OBJECT vhost-user protocol feature bit. Finally, refactor code to send response message so that all common parts both for the common REPLY_ACK case, and other data responses, can call it and avoid code repetition. Signed-off-by: Albert Esteve <aesteve@redhat.com> --- docs/interop/vhost-user.rst | 57 +++++++ hw/virtio/vhost-user.c | 174 ++++++++++++++++++++-- include/hw/virtio/vhost-backend.h | 3 + subprojects/libvhost-user/libvhost-user.c | 118 +++++++++++++++ subprojects/libvhost-user/libvhost-user.h | 55 ++++++- 5 files changed, 393 insertions(+), 14 deletions(-)