Linux supports running the RPMsg protocol over the VirtIO transport protocol, but currently there is only support for VirtIO clients and no support for a VirtIO server. This patch adds a vhost-based RPMsg server implementation.
Signed-off-by: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com --- drivers/vhost/Kconfig | 7 + drivers/vhost/Makefile | 3 + drivers/vhost/rpmsg.c | 372 ++++++++++++++++++++++++++++++++++++++++++++ drivers/vhost/vhost_rpmsg.h | 74 +++++++++ 4 files changed, 456 insertions(+) create mode 100644 drivers/vhost/rpmsg.c create mode 100644 drivers/vhost/vhost_rpmsg.h
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig index 2c75d16..c2113db 100644 --- a/drivers/vhost/Kconfig +++ b/drivers/vhost/Kconfig @@ -38,6 +38,13 @@ config VHOST_NET To compile this driver as a module, choose M here: the module will be called vhost_net.
+config VHOST_RPMSG + tristate + depends on VHOST + ---help--- + Vhost RPMsg API allows vhost drivers to communicate with VirtIO + drivers, using the RPMsg over VirtIO protocol. + config VHOST_SCSI tristate "VHOST_SCSI TCM fabric driver" depends on TARGET_CORE && EVENTFD diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile index f3e1897..9cf459d 100644 --- a/drivers/vhost/Makefile +++ b/drivers/vhost/Makefile @@ -2,6 +2,9 @@ obj-$(CONFIG_VHOST_NET) += vhost_net.o vhost_net-y := net.o
+obj-$(CONFIG_VHOST_RPMSG) += vhost_rpmsg.o +vhost_rpmsg-y := rpmsg.o + obj-$(CONFIG_VHOST_SCSI) += vhost_scsi.o vhost_scsi-y := scsi.o
diff --git a/drivers/vhost/rpmsg.c b/drivers/vhost/rpmsg.c new file mode 100644 index 00000000..609b9cf --- /dev/null +++ b/drivers/vhost/rpmsg.c @@ -0,0 +1,372 @@ +/* SPDX-License-Identifier: (GPL-2.0-only) */ +/* + * Copyright(c) 2020 Intel Corporation. All rights reserved. + * + * Author: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com + * + * vhost-RPMsg VirtIO interface + */ + +#include <linux/compat.h> +#include <linux/file.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/vhost.h> +#include <linux/virtio_rpmsg.h> +#include <uapi/linux/rpmsg.h> + +#include "vhost.h" +#include "vhost_rpmsg.h" + +/* + * All virtio-rpmsg virtual queue kicks always come with just one buffer - + * either input or output + */ +static int vhost_rpmsg_get_single(struct vhost_virtqueue *vq) +{ + struct vhost_rpmsg *vr = container_of(vq->dev, struct vhost_rpmsg, dev); + unsigned int out, in; + int head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), + &out, &in, NULL, NULL); + if (head < 0) { + vq_err(vq, "%s(): error %d getting buffer\n", + __func__, head); + return head; + } + + /* Nothing new? */ + if (head == vq->num) + return head; + + if (vq == &vr->vq[VIRTIO_RPMSG_RESPONSE] && (out || in != 1)) { + vq_err(vq, + "%s(): invalid %d input and %d output in response queue\n", + __func__, in, out); + goto return_buf; + } + + if (vq == &vr->vq[VIRTIO_RPMSG_REQUEST] && (in || out != 1)) { + vq_err(vq, + "%s(): invalid %d input and %d output in request queue\n", + __func__, in, out); + goto return_buf; + } + + return head; + +return_buf: + /* + * FIXME: might need to return the buffer using vhost_add_used() + * or vhost_discard_vq_desc(). vhost_discard_vq_desc() is + * described as "being useful for error handling," but it makes + * the thus discarded buffers "unseen," so next time we look we + * retrieve them again? + */ + return -EINVAL; +} + +static const struct vhost_rpmsg_ept *vhost_rpmsg_ept_find(struct vhost_rpmsg *vr, + int addr) +{ + unsigned int i; + + for (i = 0; i < vr->n_epts; i++) + if (vr->ept[i].addr == addr) + return vr->ept + i; + + return NULL; +} + +/* + * if len < 0, then for reading a request, the complete virtual queue buffer + * size is prepared, for sending a response, the length in the iterator is used + */ +int vhost_rpmsg_start_lock(struct vhost_rpmsg *vr, + struct vhost_rpmsg_iter *iter, + unsigned int qid, ssize_t len) + __acquires(vq->mutex) +{ + struct vhost_virtqueue *vq = vr->vq + qid; + size_t tmp; + + if (qid >= VIRTIO_RPMSG_NUM_OF_VQS) + return -EINVAL; + + iter->vq = vq; + + mutex_lock(&vq->mutex); + vhost_disable_notify(&vr->dev, vq); + + iter->head = vhost_rpmsg_get_single(vq); + if (iter->head == vq->num) + iter->head = -EAGAIN; + + if (iter->head < 0) + goto unlock; + + tmp = vq->iov[0].iov_len; + if (tmp < sizeof(iter->rhdr)) { + vq_err(vq, "%s(): size %zu too small\n", __func__, tmp); + iter->head = -ENOBUFS; + goto return_buf; + } + + switch (qid) { + case VIRTIO_RPMSG_REQUEST: + if (len < 0) { + len = tmp - sizeof(iter->rhdr); + } else if (tmp < sizeof(iter->rhdr) + len) { + iter->head = -ENOBUFS; + goto return_buf; + } + + /* len is now the size of the payload */ + iov_iter_init(&iter->iov_iter, WRITE, + vq->iov, 1, sizeof(iter->rhdr) + len); + + /* Read the RPMSG header with endpoint addresses */ + tmp = copy_from_iter(&iter->rhdr, sizeof(iter->rhdr), + &iter->iov_iter); + if (tmp != sizeof(iter->rhdr)) { + vq_err(vq, "%s(): got %zu instead of %zu\n", __func__, + tmp, sizeof(iter->rhdr)); + iter->head = -EIO; + goto return_buf; + } + + iter->ept = vhost_rpmsg_ept_find(vr, iter->rhdr.dst); + if (!iter->ept) { + vq_err(vq, "%s(): no endpoint with address %d\n", + __func__, iter->rhdr.dst); + iter->head = -ENOENT; + goto return_buf; + } + + /* Let the endpoint read the payload */ + if (iter->ept->read) { + ssize_t ret = iter->ept->read(vr, iter); + if (ret < 0) { + iter->head = ret; + goto return_buf; + } + + iter->rhdr.len = ret; + } else { + iter->rhdr.len = 0; + } + + /* Prepare for the response phase */ + iter->rhdr.dst = iter->rhdr.src; + iter->rhdr.src = iter->ept->addr; + + break; + case VIRTIO_RPMSG_RESPONSE: + if (!iter->ept && iter->rhdr.dst != RPMSG_NS_ADDR) { + /* + * Usually the iterator is configured when processing a + * message on the request queue, but it's also possible + * to send a message on the response queue without a + * preceding request, in that case the iterator must + * contain source and destination addresses. + */ + iter->ept = vhost_rpmsg_ept_find(vr, iter->rhdr.src); + if (!iter->ept) { + iter->head = -ENOENT; + goto return_buf; + } + } + + if (len < 0) { + len = tmp - sizeof(iter->rhdr); + } else if (tmp < sizeof(iter->rhdr) + len) { + iter->head = -ENOBUFS; + goto return_buf; + } else { + iter->rhdr.len = len; + } + + /* len is now the size of the payload */ + iov_iter_init(&iter->iov_iter, READ, + vq->iov, 1, sizeof(iter->rhdr) + len); + + /* Write the RPMSG header with endpoint addresses */ + tmp = copy_to_iter(&iter->rhdr, sizeof(iter->rhdr), + &iter->iov_iter); + if (tmp != sizeof(iter->rhdr)) { + iter->head = -EIO; + goto return_buf; + } + + /* Let the endpoint write the payload */ + if (iter->ept && iter->ept->write) { + ssize_t ret = iter->ept->write(vr, iter); + if (ret < 0) { + iter->head = ret; + goto return_buf; + } + } + + break; + } + + return 0; + +return_buf: + /* + * FIXME: vhost_discard_vq_desc() or vhost_add_used(), see comment in + * vhost_rpmsg_get_single() + */ +unlock: + vhost_enable_notify(&vr->dev, vq); + mutex_unlock(&vq->mutex); + + return iter->head; +} +EXPORT_SYMBOL_GPL(vhost_rpmsg_start_lock); + +size_t vhost_rpmsg_copy(struct vhost_rpmsg *vr, struct vhost_rpmsg_iter *iter, + void *data, size_t size) +{ + /* + * We could check for excess data, but copy_{to,from}_iter() don't do + * that either + */ + if (iter->vq == vr->vq + VIRTIO_RPMSG_RESPONSE) + return copy_to_iter(data, size, &iter->iov_iter); + + return copy_from_iter(data, size, &iter->iov_iter); +} +EXPORT_SYMBOL_GPL(vhost_rpmsg_copy); + +int vhost_rpmsg_finish_unlock(struct vhost_rpmsg *vr, + struct vhost_rpmsg_iter *iter) + __releases(vq->mutex) +{ + if (iter->head >= 0) + vhost_add_used_and_signal(iter->vq->dev, iter->vq, iter->head, + iter->rhdr.len + sizeof(iter->rhdr)); + + vhost_enable_notify(&vr->dev, iter->vq); + mutex_unlock(&iter->vq->mutex); + + return iter->head; +} +EXPORT_SYMBOL_GPL(vhost_rpmsg_finish_unlock); + +/* + * Return false to terminate the external loop only if we fail to obtain either + * a request or a response buffer + */ +static bool handle_rpmsg_req_single(struct vhost_rpmsg *vr, + struct vhost_virtqueue *vq) +{ + struct vhost_rpmsg_iter iter; + int ret = vhost_rpmsg_start_lock(vr, &iter, VIRTIO_RPMSG_REQUEST, + -EINVAL); + if (!ret) + ret = vhost_rpmsg_finish_unlock(vr, &iter); + if (ret < 0) { + if (ret != -EAGAIN) + vq_err(vq, "%s(): RPMSG processing failed %d\n", + __func__, ret); + return false; + } + + if (!iter.ept->write) + return true; + + ret = vhost_rpmsg_start_lock(vr, &iter, VIRTIO_RPMSG_RESPONSE, + -EINVAL); + if (!ret) + ret = vhost_rpmsg_finish_unlock(vr, &iter); + if (ret < 0) { + vq_err(vq, "%s(): RPMSG finalising failed %d\n", __func__, ret); + return false; + } + + return true; +} + +static void handle_rpmsg_req_kick(struct vhost_work *work) +{ + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, + poll.work); + struct vhost_rpmsg *vr = container_of(vq->dev, struct vhost_rpmsg, dev); + + while (handle_rpmsg_req_single(vr, vq)) + ; +} + +/* + * initialise two virtqueues with an array of endpoints, + * request and response callbacks + */ +void vhost_rpmsg_init(struct vhost_rpmsg *vr, const struct vhost_rpmsg_ept *ept, + unsigned int n_epts) +{ + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(vr->vq); i++) + vr->vq_p[i] = &vr->vq[i]; + + /* vq[0]: host -> guest, vq[1]: host <- guest */ + vr->vq[VIRTIO_RPMSG_REQUEST].handle_kick = handle_rpmsg_req_kick; + + vr->ept = ept; + vr->n_epts = n_epts; + + vhost_dev_init(&vr->dev, vr->vq_p, VIRTIO_RPMSG_NUM_OF_VQS, + UIO_MAXIOV, 0, 0, NULL); +} +EXPORT_SYMBOL_GPL(vhost_rpmsg_init); + +void vhost_rpmsg_destroy(struct vhost_rpmsg *vr) +{ + if (vhost_dev_has_owner(&vr->dev)) + vhost_poll_flush(&vr->vq[VIRTIO_RPMSG_REQUEST].poll); + + vhost_dev_cleanup(&vr->dev); +} +EXPORT_SYMBOL_GPL(vhost_rpmsg_destroy); + +/* send namespace */ +int vhost_rpmsg_ns_announce(struct vhost_rpmsg *vr, const char *name, + unsigned int src) +{ + struct vhost_rpmsg_iter iter = { + .rhdr = { + .src = 0, + .dst = RPMSG_NS_ADDR, + .flags = RPMSG_NS_CREATE, /* rpmsg_recv_single() */ + }, + }; + struct rpmsg_ns_msg ns = { + .addr = src, + .flags = RPMSG_NS_CREATE, /* for rpmsg_ns_cb() */ + }; + int ret = vhost_rpmsg_start_lock(vr, &iter, VIRTIO_RPMSG_RESPONSE, + sizeof(ns)); + + if (ret < 0) + return ret; + + strlcpy(ns.name, name, sizeof(ns.name)); + + ret = vhost_rpmsg_copy(vr, &iter, &ns, sizeof(ns)); + if (ret != sizeof(ns)) + vq_err(iter.vq, "%s(): added %d instead of %zu bytes\n", + __func__, ret, sizeof(ns)); + + ret = vhost_rpmsg_finish_unlock(vr, &iter); + if (ret < 0) + vq_err(iter.vq, "%s(): namespace announcement failed: %d\n", + __func__, ret); + + return ret; +} +EXPORT_SYMBOL_GPL(vhost_rpmsg_ns_announce); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Intel, Inc."); +MODULE_DESCRIPTION("Vhost RPMsg API"); diff --git a/drivers/vhost/vhost_rpmsg.h b/drivers/vhost/vhost_rpmsg.h new file mode 100644 index 00000000..5248ac9 --- /dev/null +++ b/drivers/vhost/vhost_rpmsg.h @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: (GPL-2.0) */ +/* + * Copyright(c) 2020 Intel Corporation. All rights reserved. + * + * Author: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com + */ + +#ifndef VHOST_RPMSG_H +#define VHOST_RPMSG_H + +#include <linux/uio.h> +#include <linux/virtio_rpmsg.h> + +#include "vhost.h" + +/* RPMsg uses two VirtQueues: one for each direction */ +enum { + VIRTIO_RPMSG_RESPONSE, /* RPMsg response (host->guest) buffers */ + VIRTIO_RPMSG_REQUEST, /* RPMsg request (guest->host) buffers */ + /* Keep last */ + VIRTIO_RPMSG_NUM_OF_VQS, +}; + +struct vhost_rpmsg_ept; + +struct vhost_rpmsg_iter { + struct iov_iter iov_iter; + struct rpmsg_hdr rhdr; + struct vhost_virtqueue *vq; + const struct vhost_rpmsg_ept *ept; + int head; + void *priv; +}; + +struct vhost_rpmsg { + struct vhost_dev dev; + struct vhost_virtqueue vq[VIRTIO_RPMSG_NUM_OF_VQS]; + struct vhost_virtqueue *vq_p[VIRTIO_RPMSG_NUM_OF_VQS]; + const struct vhost_rpmsg_ept *ept; + unsigned int n_epts; +}; + +struct vhost_rpmsg_ept { + ssize_t (*read)(struct vhost_rpmsg *, struct vhost_rpmsg_iter *); + ssize_t (*write)(struct vhost_rpmsg *, struct vhost_rpmsg_iter *); + int addr; +}; + +static inline size_t vhost_rpmsg_iter_len(const struct vhost_rpmsg_iter *iter) +{ + return iter->rhdr.len; +} + +#define VHOST_RPMSG_ITER(_src, _dst) { \ + .rhdr = { \ + .src = _src, \ + .dst = _dst, \ + }, \ + } + +void vhost_rpmsg_init(struct vhost_rpmsg *vr, const struct vhost_rpmsg_ept *ept, + unsigned int n_epts); +void vhost_rpmsg_destroy(struct vhost_rpmsg *vr); +int vhost_rpmsg_ns_announce(struct vhost_rpmsg *vr, const char *name, + unsigned int src); +int vhost_rpmsg_start_lock(struct vhost_rpmsg *vr, + struct vhost_rpmsg_iter *iter, + unsigned int qid, ssize_t len); +size_t vhost_rpmsg_copy(struct vhost_rpmsg *vr, struct vhost_rpmsg_iter *iter, + void *data, size_t size); +int vhost_rpmsg_finish_unlock(struct vhost_rpmsg *vr, + struct vhost_rpmsg_iter *iter); + +#endif