119 lines
3.7 KiB
Diff
119 lines
3.7 KiB
Diff
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Mon, 27 Jan 2020 19:01:44 +0000
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Subject: [PATCH] contrib/libvhost-user: Protect slave fd with mutex
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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In future patches we'll be performing commands on the slave-fd driven
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by commands on queues, since those queues will be driven by individual
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threads we need to make sure they don't attempt to use the slave-fd
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for multiple commands in parallel.
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit c25c02b9e6a196be87a818f459c426556b24770d)
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---
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contrib/libvhost-user/libvhost-user.c | 24 ++++++++++++++++++++----
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contrib/libvhost-user/libvhost-user.h | 3 +++
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2 files changed, 23 insertions(+), 4 deletions(-)
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diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
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index ec27b78ff1..63e41062a4 100644
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--- a/contrib/libvhost-user/libvhost-user.c
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+++ b/contrib/libvhost-user/libvhost-user.c
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@@ -392,26 +392,37 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
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return vu_message_write(dev, conn_fd, vmsg);
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}
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+/*
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+ * Processes a reply on the slave channel.
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+ * Entered with slave_mutex held and releases it before exit.
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+ * Returns true on success.
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+ */
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static bool
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vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
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{
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VhostUserMsg msg_reply;
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+ bool result = false;
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if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) == 0) {
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- return true;
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+ result = true;
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+ goto out;
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}
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if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) {
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- return false;
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+ goto out;
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}
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if (msg_reply.request != vmsg->request) {
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DPRINT("Received unexpected msg type. Expected %d received %d",
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vmsg->request, msg_reply.request);
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- return false;
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+ goto out;
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}
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- return msg_reply.payload.u64 == 0;
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+ result = msg_reply.payload.u64 == 0;
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+
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+out:
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+ pthread_mutex_unlock(&dev->slave_mutex);
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+ return result;
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}
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/* Kick the log_call_fd if required. */
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@@ -1105,10 +1116,13 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
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return false;
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}
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+ pthread_mutex_lock(&dev->slave_mutex);
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if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
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+ pthread_mutex_unlock(&dev->slave_mutex);
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return false;
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}
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+ /* Also unlocks the slave_mutex */
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return vu_process_message_reply(dev, &vmsg);
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}
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@@ -1628,6 +1642,7 @@ vu_deinit(VuDev *dev)
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close(dev->slave_fd);
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dev->slave_fd = -1;
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}
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+ pthread_mutex_destroy(&dev->slave_mutex);
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if (dev->sock != -1) {
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close(dev->sock);
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@@ -1663,6 +1678,7 @@ vu_init(VuDev *dev,
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dev->remove_watch = remove_watch;
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dev->iface = iface;
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dev->log_call_fd = -1;
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+ pthread_mutex_init(&dev->slave_mutex, NULL);
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dev->slave_fd = -1;
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dev->max_queues = max_queues;
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diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
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index 46b600799b..1844b6f8d4 100644
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--- a/contrib/libvhost-user/libvhost-user.h
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+++ b/contrib/libvhost-user/libvhost-user.h
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@@ -19,6 +19,7 @@
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#include <stddef.h>
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#include <sys/poll.h>
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#include <linux/vhost.h>
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+#include <pthread.h>
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#include "standard-headers/linux/virtio_ring.h"
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/* Based on qemu/hw/virtio/vhost-user.c */
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@@ -355,6 +356,8 @@ struct VuDev {
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VuVirtq *vq;
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VuDevInflightInfo inflight_info;
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int log_call_fd;
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+ /* Must be held while using slave_fd */
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+ pthread_mutex_t slave_mutex;
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int slave_fd;
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uint64_t log_size;
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uint8_t *log_table;
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