On Mon, Oct 21, 2019 at 1:09 PM Dr. David Alan Gilbert (git)
<dgilb...@redhat.com> wrote:
>
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Pop queue elements off queues, copy the data from them and
> pass that to fuse.
>
> Note: 'out' in a VuVirtqElement is from QEMU
> 'in' in libfuse is into the daemon
>
> So we read from the out iov's to get a fuse_in_header
>
> When we get a kick we've got to read all the elements until the queue
> is empty.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> contrib/virtiofsd/fuse_i.h | 2 +
> contrib/virtiofsd/fuse_virtio.c | 99 ++++++++++++++++++++++++++++++++-
> 2 files changed, 98 insertions(+), 3 deletions(-)
>
> diff --git a/contrib/virtiofsd/fuse_i.h b/contrib/virtiofsd/fuse_i.h
> index ea55f618a5..5b6ef09df5 100644
> --- a/contrib/virtiofsd/fuse_i.h
> +++ b/contrib/virtiofsd/fuse_i.h
> @@ -14,6 +14,7 @@
> #include "fuse_lowlevel.h"
>
> struct fv_VuDev;
> +struct fv_QueueInfo;
>
> struct fuse_req {
> struct fuse_session *se;
> @@ -75,6 +76,7 @@ struct fuse_chan {
> pthread_mutex_t lock;
> int ctr;
> int fd;
> + struct fv_QueueInfo *qi;
> };
>
> /**
> diff --git a/contrib/virtiofsd/fuse_virtio.c b/contrib/virtiofsd/fuse_virtio.c
> index 0513531c13..e189511729 100644
> --- a/contrib/virtiofsd/fuse_virtio.c
> +++ b/contrib/virtiofsd/fuse_virtio.c
> @@ -32,6 +32,7 @@
>
> #include "contrib/libvhost-user/libvhost-user.h"
>
> +struct fv_VuDev;
> struct fv_QueueInfo {
> pthread_t thread;
> struct fv_VuDev *virtio_dev;
> @@ -101,10 +102,42 @@ static void fv_panic(VuDev *dev, const char *err)
> exit(EXIT_FAILURE);
> }
>
> +/*
> + * Copy from an iovec into a fuse_buf (memory only)
> + * Caller must ensure there is space
> + */
> +static void copy_from_iov(struct fuse_buf *buf, size_t out_num,
> + const struct iovec *out_sg)
> +{
> + void *dest = buf->mem;
> +
> + while (out_num) {
> + size_t onelen = out_sg->iov_len;
> + memcpy(dest, out_sg->iov_base, onelen);
> + dest += onelen;
> + out_sg++;
> + out_num--;
> + }
> +}
Or iov_to_buf()
Just found out that vhost-user-blk.c should probably link too with
util/iov.o, instead of copying the code.
> +
> /* Thread function for individual queues, created when a queue is 'started'
> */
> static void *fv_queue_thread(void *opaque)
> {
> struct fv_QueueInfo *qi = opaque;
> + struct VuDev *dev = &qi->virtio_dev->dev;
> + struct VuVirtq *q = vu_get_queue(dev, qi->qidx);
> + struct fuse_session *se = qi->virtio_dev->se;
> + struct fuse_chan ch;
> + struct fuse_buf fbuf;
> +
> + fbuf.mem = NULL;
> + fbuf.flags = 0;
> +
> + fuse_mutex_init(&ch.lock);
> + ch.fd = (int)0xdaff0d111;
> + ch.ctr = 1;
> + ch.qi = qi;
> +
> fuse_log(FUSE_LOG_INFO, "%s: Start for queue %d kick_fd %d\n", __func__,
> qi->qidx, qi->kick_fd);
> while (1) {
> @@ -141,11 +174,71 @@ static void *fv_queue_thread(void *opaque)
> fuse_log(FUSE_LOG_ERR, "Eventfd_read for queue: %m\n");
> break;
> }
> - if (qi->virtio_dev->se->debug) {
> - fprintf(stderr, "%s: Queue %d gave evalue: %zx\n", __func__,
> - qi->qidx, (size_t)evalue);
> + /* out is from guest, in is too guest */
> + unsigned int in_bytes, out_bytes;
> + vu_queue_get_avail_bytes(dev, q, &in_bytes, &out_bytes, ~0, ~0);
> +
> + fuse_log(FUSE_LOG_DEBUG,
> + "%s: Queue %d gave evalue: %zx available: in: %u out: %u\n",
> + __func__, qi->qidx, (size_t)evalue, in_bytes, out_bytes);
> +
> + while (1) {
> + /*
> + * An element contains one request and the space to send our
> + * response They're spread over multiple descriptors in a
> + * scatter/gather set and we can't trust the guest to keep them
> + * still; so copy in/out.
> + */
> + VuVirtqElement *elem = vu_queue_pop(dev, q,
> sizeof(VuVirtqElement));
> + if (!elem) {
> + break;
> + }
> +
> + if (!fbuf.mem) {
> + fbuf.mem = malloc(se->bufsize);
> + assert(fbuf.mem);
> + assert(se->bufsize > sizeof(struct fuse_in_header));
> + }
> + /* The 'out' part of the elem is from qemu */
> + unsigned int out_num = elem->out_num;
> + struct iovec *out_sg = elem->out_sg;
> + size_t out_len = iov_length(out_sg, out_num);
> + fuse_log(FUSE_LOG_DEBUG,
> + "%s: elem %d: with %d out desc of length %zd\n",
> __func__,
> + elem->index, out_num, out_len);
> +
> + /*
> + * The elem should contain a 'fuse_in_header' (in to fuse)
> + * plus the data based on the len in the header.
> + */
> + if (out_len < sizeof(struct fuse_in_header)) {
> + fuse_log(FUSE_LOG_ERR, "%s: elem %d too short for
> in_header\n",
> + __func__, elem->index);
> + assert(0); /* TODO */
> + }
> + if (out_len > se->bufsize) {
> + fuse_log(FUSE_LOG_ERR, "%s: elem %d too large for buffer\n",
> + __func__, elem->index);
> + assert(0); /* TODO */
> + }
> + copy_from_iov(&fbuf, out_num, out_sg);
> + fbuf.size = out_len;
> +
> + /* TODO! Endianness of header */
> +
> + /* TODO: Fixup fuse_send_msg */
> + /* TODO: Add checks for fuse_session_exited */
> + fuse_session_process_buf_int(se, &fbuf, &ch);
> +
> + /* TODO: vu_queue_push(dev, q, elem, qi->write_count); */
> + vu_queue_notify(dev, q);
> +
> + free(elem);
> + elem = NULL;
> }
> }
> + pthread_mutex_destroy(&ch.lock);
> + free(fbuf.mem);
>
> return NULL;
> }
> --
> 2.23.0
>
>
--
Marc-André Lureau
