From b4af2eff8ecadb4e2c9520602455f77fac2cb943 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Mon, 27 Jan 2020 19:01:02 +0100 Subject: [PATCH 031/116] virtiofsd: Start reading commands from queue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Dr. David Alan Gilbert Message-id: <20200127190227.40942-28-dgilbert@redhat.com> Patchwork-id: 93484 O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 027/112] virtiofsd: Start reading commands from queue Bugzilla: 1694164 RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Sergio Lopez Pascual From: "Dr. David Alan Gilbert" 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 Reviewed-by: Daniel P. Berrangé Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit b509e1228b3e5eb83c14819045988999fc2dbd1b) Signed-off-by: Miroslav Rezanina --- tools/virtiofsd/fuse_i.h | 2 + tools/virtiofsd/fuse_virtio.c | 99 +++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 98 insertions(+), 3 deletions(-) diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h index ec04449..1126723 100644 --- a/tools/virtiofsd/fuse_i.h +++ b/tools/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/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index 05e7258..3841b20 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -12,6 +12,7 @@ */ #include "qemu/osdep.h" +#include "qemu/iov.h" #include "fuse_virtio.h" #include "fuse_i.h" #include "standard-headers/linux/fuse.h" @@ -32,6 +33,7 @@ #include "contrib/libvhost-user/libvhost-user.h" +struct fv_VuDev; struct fv_QueueInfo { pthread_t thread; struct fv_VuDev *virtio_dev; @@ -101,10 +103,41 @@ 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--; + } +} + /* 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.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_size(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; } -- 1.8.3.1