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.
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 <aest...@redhat.com>
---
docs/interop/vhost-user.rst | 57 ++++++++++
hw/virtio/vhost-user.c | 168 +++++++++++++++++++++++++++---
include/hw/virtio/vhost-backend.h | 3 +
3 files changed, 216 insertions(+), 12 deletions(-)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 5a070adbc1..415bb47a19 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -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
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 8dcf049d42..08ab256613 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -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 +1613,139 @@ 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 **errp)
+{
+ 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;
+
+ return !qio_channel_writev_all(ioc, iov, ARRAY_SIZE(iov), errp);
+}
+
+static bool
+vhost_user_backend_send_dmabuf_fd(QIOChannel *ioc, VhostUserHeader *hdr,
+ VhostUserPayload *payload, Error **errp)
+{
+ hdr->size = sizeof(payload->u64);
+ return vhost_user_send_resp(ioc, hdr, payload, errp);
+}
+
+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;
+ Error *local_err = NULL;
+ 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, &local_err)) {
+ error_report_err(local_err);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static void close_backend_channel(struct vhost_user *u)
{
g_source_destroy(u->backend_src);
@@ -1658,6 +1803,16 @@ 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;
@@ -1668,21 +1823,10 @@ 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))
{
+ if (!vhost_user_send_resp(ioc, &hdr, &payload, &local_err)) {
error_report_err(local_err);
goto err;
}
diff --git a/include/hw/virtio/vhost-backend.h
b/include/hw/virtio/vhost-backend.h
index 31a251a9f5..1860b541d8 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -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 */
--
2.41.0
