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qemu-kvm/SOURCES/kvm-virtiofsd-Start-reading...

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From b4af2eff8ecadb4e2c9520602455f77fac2cb943 Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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 <dgilbert@redhat.com>
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 <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>
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 <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 b509e1228b3e5eb83c14819045988999fc2dbd1b)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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
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