qemu-kvm/SOURCES/kvm-contrib-libvhost-user-Protect-slave-fd-with-mutex.patch

135 lines
4.3 KiB
Diff

From 548de8acbf0137b6e49a14b63682badfff037d23 Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Date: Mon, 27 Jan 2020 19:01:44 +0100
Subject: [PATCH 073/116] contrib/libvhost-user: Protect slave fd with mutex
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: <20200127190227.40942-70-dgilbert@redhat.com>
Patchwork-id: 93523
O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 069/112] contrib/libvhost-user: Protect slave fd with mutex
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>
In future patches we'll be performing commands on the slave-fd driven
by commands on queues, since those queues will be driven by individual
threads we need to make sure they don't attempt to use the slave-fd
for multiple commands in parallel.
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 c25c02b9e6a196be87a818f459c426556b24770d)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
contrib/libvhost-user/libvhost-user.c | 24 ++++++++++++++++++++----
contrib/libvhost-user/libvhost-user.h | 3 +++
2 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index ec27b78..63e4106 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -392,26 +392,37 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
return vu_message_write(dev, conn_fd, vmsg);
}
+/*
+ * Processes a reply on the slave channel.
+ * Entered with slave_mutex held and releases it before exit.
+ * Returns true on success.
+ */
static bool
vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
{
VhostUserMsg msg_reply;
+ bool result = false;
if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) == 0) {
- return true;
+ result = true;
+ goto out;
}
if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) {
- return false;
+ goto out;
}
if (msg_reply.request != vmsg->request) {
DPRINT("Received unexpected msg type. Expected %d received %d",
vmsg->request, msg_reply.request);
- return false;
+ goto out;
}
- return msg_reply.payload.u64 == 0;
+ result = msg_reply.payload.u64 == 0;
+
+out:
+ pthread_mutex_unlock(&dev->slave_mutex);
+ return result;
}
/* Kick the log_call_fd if required. */
@@ -1105,10 +1116,13 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
return false;
}
+ pthread_mutex_lock(&dev->slave_mutex);
if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
+ pthread_mutex_unlock(&dev->slave_mutex);
return false;
}
+ /* Also unlocks the slave_mutex */
return vu_process_message_reply(dev, &vmsg);
}
@@ -1628,6 +1642,7 @@ vu_deinit(VuDev *dev)
close(dev->slave_fd);
dev->slave_fd = -1;
}
+ pthread_mutex_destroy(&dev->slave_mutex);
if (dev->sock != -1) {
close(dev->sock);
@@ -1663,6 +1678,7 @@ vu_init(VuDev *dev,
dev->remove_watch = remove_watch;
dev->iface = iface;
dev->log_call_fd = -1;
+ pthread_mutex_init(&dev->slave_mutex, NULL);
dev->slave_fd = -1;
dev->max_queues = max_queues;
diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index 46b6007..1844b6f 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -19,6 +19,7 @@
#include <stddef.h>
#include <sys/poll.h>
#include <linux/vhost.h>
+#include <pthread.h>
#include "standard-headers/linux/virtio_ring.h"
/* Based on qemu/hw/virtio/vhost-user.c */
@@ -355,6 +356,8 @@ struct VuDev {
VuVirtq *vq;
VuDevInflightInfo inflight_info;
int log_call_fd;
+ /* Must be held while using slave_fd */
+ pthread_mutex_t slave_mutex;
int slave_fd;
uint64_t log_size;
uint8_t *log_table;
--
1.8.3.1