From 160947666276c5b7f6bca4d746bcac2966635d79 Mon Sep 17 00:00:00 2001 From: Albert Esteve Date: Mon, 2 Oct 2023 08:57:05 +0200 Subject: [PATCH] vhost-user: add shared_object msg 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 Message-Id: <20231002065706.94707-4-aesteve@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/interop/vhost-user.rst | 57 ++++++++++ hw/virtio/vhost-user.c | 167 +++++++++++++++++++++++++++--- include/hw/virtio/vhost-backend.h | 3 + include/hw/virtio/vhost-user.h | 1 + 4 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 a096335921..3766b415f8 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" @@ -100,6 +102,7 @@ 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; @@ -108,6 +111,9 @@ 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; @@ -181,6 +187,10 @@ typedef struct VhostUserInflight { uint16_t queue_size; } VhostUserInflight; +typedef struct VhostUserShared { + unsigned char uuid[16]; +} VhostUserShared; + typedef struct { VhostUserRequest request; @@ -205,6 +215,7 @@ typedef union { VhostUserCryptoSession session; VhostUserVringArea area; VhostUserInflight inflight; + VhostUserShared object; } VhostUserPayload; typedef struct VhostUserMsg { @@ -1580,6 +1591,139 @@ 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); @@ -1637,6 +1781,16 @@ 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; @@ -1647,21 +1801,10 @@ 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 */ diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h index 80e2b4a463..9f9ddf878d 100644 --- a/include/hw/virtio/vhost-user.h +++ b/include/hw/virtio/vhost-user.h @@ -29,6 +29,7 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14, 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 };