From bb1f691dc410ce11ac9675ced70e78a3ce2511b0 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Mon, 27 Jan 2020 19:01:03 +0100 Subject: [PATCH 032/116] virtiofsd: Send replies to messages MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Dr. David Alan Gilbert Message-id: <20200127190227.40942-29-dgilbert@redhat.com> Patchwork-id: 93485 O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 028/112] virtiofsd: Send replies to messages Bugzilla: 1694164 RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Sergio Lopez Pascual From: "Dr. David Alan Gilbert" Route fuse out messages back through the same queue elements that had the command that triggered the request. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Daniel P. Berrangé Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit df57ba919ec3edef9cc208d35685095e6e92713e) Signed-off-by: Miroslav Rezanina --- tools/virtiofsd/fuse_lowlevel.c | 4 ++ tools/virtiofsd/fuse_virtio.c | 107 ++++++++++++++++++++++++++++++++++++++-- tools/virtiofsd/fuse_virtio.h | 4 ++ 3 files changed, 111 insertions(+), 4 deletions(-) diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c index af09fa2..380d93b 100644 --- a/tools/virtiofsd/fuse_lowlevel.c +++ b/tools/virtiofsd/fuse_lowlevel.c @@ -171,6 +171,10 @@ static int fuse_send_msg(struct fuse_session *se, struct fuse_chan *ch, } } + if (fuse_lowlevel_is_virtio(se)) { + return virtio_send_msg(se, ch, iov, count); + } + abort(); /* virtio should have taken it before here */ return 0; } diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index 3841b20..05d0e29 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -41,6 +41,9 @@ struct fv_QueueInfo { /* Our queue index, corresponds to array position */ int qidx; int kick_fd; + + /* The element for the command currently being processed */ + VuVirtqElement *qe; }; /* @@ -121,6 +124,105 @@ static void copy_from_iov(struct fuse_buf *buf, size_t out_num, } } +/* + * Copy from one iov to another, the given number of bytes + * The caller must have checked sizes. + */ +static void copy_iov(struct iovec *src_iov, int src_count, + struct iovec *dst_iov, int dst_count, size_t to_copy) +{ + size_t dst_offset = 0; + /* Outer loop copies 'src' elements */ + while (to_copy) { + assert(src_count); + size_t src_len = src_iov[0].iov_len; + size_t src_offset = 0; + + if (src_len > to_copy) { + src_len = to_copy; + } + /* Inner loop copies contents of one 'src' to maybe multiple dst. */ + while (src_len) { + assert(dst_count); + size_t dst_len = dst_iov[0].iov_len - dst_offset; + if (dst_len > src_len) { + dst_len = src_len; + } + + memcpy(dst_iov[0].iov_base + dst_offset, + src_iov[0].iov_base + src_offset, dst_len); + src_len -= dst_len; + to_copy -= dst_len; + src_offset += dst_len; + dst_offset += dst_len; + + assert(dst_offset <= dst_iov[0].iov_len); + if (dst_offset == dst_iov[0].iov_len) { + dst_offset = 0; + dst_iov++; + dst_count--; + } + } + src_iov++; + src_count--; + } +} + +/* + * Called back by ll whenever it wants to send a reply/message back + * The 1st element of the iov starts with the fuse_out_header + * 'unique'==0 means it's a notify message. + */ +int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, + struct iovec *iov, int count) +{ + VuVirtqElement *elem; + VuVirtq *q; + + assert(count >= 1); + assert(iov[0].iov_len >= sizeof(struct fuse_out_header)); + + struct fuse_out_header *out = iov[0].iov_base; + /* TODO: Endianness! */ + + size_t tosend_len = iov_size(iov, count); + + /* unique == 0 is notification, which we don't support */ + assert(out->unique); + /* For virtio we always have ch */ + assert(ch); + elem = ch->qi->qe; + q = &ch->qi->virtio_dev->dev.vq[ch->qi->qidx]; + + /* The 'in' part of the elem is to qemu */ + unsigned int in_num = elem->in_num; + struct iovec *in_sg = elem->in_sg; + size_t in_len = iov_size(in_sg, in_num); + fuse_log(FUSE_LOG_DEBUG, "%s: elem %d: with %d in desc of length %zd\n", + __func__, elem->index, in_num, in_len); + + /* + * The elem should have room for a 'fuse_out_header' (out from fuse) + * plus the data based on the len in the header. + */ + if (in_len < sizeof(struct fuse_out_header)) { + fuse_log(FUSE_LOG_ERR, "%s: elem %d too short for out_header\n", + __func__, elem->index); + return -E2BIG; + } + if (in_len < tosend_len) { + fuse_log(FUSE_LOG_ERR, "%s: elem %d too small for data len %zd\n", + __func__, elem->index, tosend_len); + return -E2BIG; + } + + copy_iov(iov, count, in_sg, in_num, tosend_len); + vu_queue_push(&se->virtio_dev->dev, q, elem, tosend_len); + vu_queue_notify(&se->virtio_dev->dev, q); + + return 0; +} + /* Thread function for individual queues, created when a queue is 'started' */ static void *fv_queue_thread(void *opaque) { @@ -226,13 +328,10 @@ static void *fv_queue_thread(void *opaque) /* 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); - + qi->qe = NULL; free(elem); elem = NULL; } diff --git a/tools/virtiofsd/fuse_virtio.h b/tools/virtiofsd/fuse_virtio.h index 23026d6..135a148 100644 --- a/tools/virtiofsd/fuse_virtio.h +++ b/tools/virtiofsd/fuse_virtio.h @@ -22,4 +22,8 @@ int virtio_session_mount(struct fuse_session *se); int virtio_loop(struct fuse_session *se); + +int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, + struct iovec *iov, int count); + #endif -- 1.8.3.1