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From bb1f691dc410ce11ac9675ced70e78a3ce2511b0 Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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 <dgilbert@redhat.com>
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 <philmd@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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 <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit df57ba919ec3edef9cc208d35685095e6e92713e)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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
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