* [Qemu-devel] [PATCH v6 0/3] ivshmem: update documentation, add client/server tools
@ 2014-09-08 9:17 David Marchand
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server David Marchand
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: David Marchand @ 2014-09-08 9:17 UTC (permalink / raw)
To: qemu-devel
Cc: kvm, mst, stefanha, claudio.fontana, armbru, arei.gonglei,
mkletzan, pbonzini, jani.kokkonen, cam
Here is a patchset containing an update on ivshmem specs documentation and
importing ivshmem server and client tools.
These tools have been written from scratch and are not related to what is
available in nahanni repository.
I put them in contrib/ directory as the qemu-doc.texi was already telling the
server was supposed to be there.
Changes since v5:
- 1st patch
* fixed remaining coding style issues
* fixed checks on snprintf return code
* prefixed all symbols to avoid pollution
* fixed spelling mistakes in comments
* fixed function descriptions in headers
* added a signal handler on SIGTERM and only unlink server socket when server exits
* fixed fd leaks I identified in client when reconnecting to a server
- 3rd patch
* remove wrong debug message
* do not delay pci bar2 register
Changes since v4:
- squashed patches 3-13 from v4 into first patch
- reused reported error when parsing arguments in server
- fixed spelling mistakes in documentation in second patch
Changes since v3:
- first patch is untouched
- just restored the Reviewed-By Claudio in second patch
- following patches 3-8 take into account Stefan's comments
- patches 9-12 take into account Gonglei's comments
- patch 13 adjusts ivshmem-server default values
- last patch introduces a change in the ivshmem client-server protocol to
check a protocol version at connect time
Changes since v2:
- fixed license issues in ivshmem client/server (I took hw/virtio/virtio-rng.c
file as a reference).
Changes since v1:
- moved client/server import patch before doc update,
- tried to re-organise the ivshmem_device_spec.txt file based on Claudio
comments (still not sure if the result is that great, comments welcome),
- incorporated comments from Claudio, Eric and Cam,
- added more details on the server <-> client messages exchange (but sorry, no
ASCII art here).
By the way, there are still some functionnalities that need description (use of
ioeventfd, the lack of irqfd support) and some parts of the ivshmem code clearly
need cleanup. I will try to address this in future patches when these first
patches are ok.
--
David Marchand
David Marchand (3):
contrib: add ivshmem client and server
docs: update ivshmem device spec
ivshmem: add check on protocol version in QEMU
Makefile | 8 +
configure | 3 +
contrib/ivshmem-client/ivshmem-client.c | 440 +++++++++++++++++++++++++++++++
contrib/ivshmem-client/ivshmem-client.h | 213 +++++++++++++++
contrib/ivshmem-client/main.c | 239 +++++++++++++++++
contrib/ivshmem-server/ivshmem-server.c | 426 ++++++++++++++++++++++++++++++
contrib/ivshmem-server/ivshmem-server.h | 165 ++++++++++++
contrib/ivshmem-server/main.c | 264 +++++++++++++++++++
docs/specs/ivshmem_device_spec.txt | 127 ++++++---
hw/misc/ivshmem.c | 27 +-
include/hw/misc/ivshmem.h | 17 ++
qemu-doc.texi | 10 +-
12 files changed, 1903 insertions(+), 36 deletions(-)
create mode 100644 contrib/ivshmem-client/ivshmem-client.c
create mode 100644 contrib/ivshmem-client/ivshmem-client.h
create mode 100644 contrib/ivshmem-client/main.c
create mode 100644 contrib/ivshmem-server/ivshmem-server.c
create mode 100644 contrib/ivshmem-server/ivshmem-server.h
create mode 100644 contrib/ivshmem-server/main.c
create mode 100644 include/hw/misc/ivshmem.h
--
1.7.10.4
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server
2014-09-08 9:17 [Qemu-devel] [PATCH v6 0/3] ivshmem: update documentation, add client/server tools David Marchand
@ 2014-09-08 9:17 ` David Marchand
2014-09-08 9:51 ` Michael S. Tsirkin
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 2/3] docs: update ivshmem device spec David Marchand
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU David Marchand
2 siblings, 1 reply; 9+ messages in thread
From: David Marchand @ 2014-09-08 9:17 UTC (permalink / raw)
To: qemu-devel
Cc: Olivier Matz, kvm, mst, stefanha, claudio.fontana, armbru,
arei.gonglei, mkletzan, pbonzini, jani.kokkonen, cam
When using ivshmem devices, notifications between guests can be sent as
interrupts using a ivshmem-server (typical use described in documentation).
The client is provided as a debug tool.
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: David Marchand <david.marchand@6wind.com>
---
Makefile | 8 +
configure | 3 +
contrib/ivshmem-client/ivshmem-client.c | 433 +++++++++++++++++++++++++++++++
contrib/ivshmem-client/ivshmem-client.h | 212 +++++++++++++++
contrib/ivshmem-client/main.c | 239 +++++++++++++++++
contrib/ivshmem-server/ivshmem-server.c | 417 +++++++++++++++++++++++++++++
contrib/ivshmem-server/ivshmem-server.h | 164 ++++++++++++
contrib/ivshmem-server/main.c | 264 +++++++++++++++++++
qemu-doc.texi | 10 +-
9 files changed, 1747 insertions(+), 3 deletions(-)
create mode 100644 contrib/ivshmem-client/ivshmem-client.c
create mode 100644 contrib/ivshmem-client/ivshmem-client.h
create mode 100644 contrib/ivshmem-client/main.c
create mode 100644 contrib/ivshmem-server/ivshmem-server.c
create mode 100644 contrib/ivshmem-server/ivshmem-server.h
create mode 100644 contrib/ivshmem-server/main.c
diff --git a/Makefile b/Makefile
index b33aaac..0575898 100644
--- a/Makefile
+++ b/Makefile
@@ -283,6 +283,14 @@ $(qga-obj-y) qemu-ga.o: $(QGALIB_GEN)
qemu-ga$(EXESUF): $(qga-obj-y) libqemuutil.a libqemustub.a
$(call LINK, $^)
+IVSHMEM_CLIENT_OBJS=$(addprefix $(SRC_PATH)/contrib/ivshmem-client/, ivshmem-client.o main.o)
+ivshmem-client$(EXESUF): $(IVSHMEM_CLIENT_OBJS)
+ $(call LINK, $^)
+
+IVSHMEM_SERVER_OBJS=$(addprefix $(SRC_PATH)/contrib/ivshmem-server/, ivshmem-server.o main.o)
+ivshmem-server$(EXESUF): $(IVSHMEM_SERVER_OBJS) libqemuutil.a libqemustub.a
+ $(call LINK, $^)
+
clean:
# avoid old build problems by removing potentially incorrect old files
rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
diff --git a/configure b/configure
index 961bf6f..a41a16c 100755
--- a/configure
+++ b/configure
@@ -4125,6 +4125,9 @@ if test "$want_tools" = "yes" ; then
if [ "$linux" = "yes" -o "$bsd" = "yes" -o "$solaris" = "yes" ] ; then
tools="qemu-nbd\$(EXESUF) $tools"
fi
+ if [ "$kvm" = "yes" ] ; then
+ tools="ivshmem-client\$(EXESUF) ivshmem-server\$(EXESUF) $tools"
+ fi
fi
if test "$softmmu" = yes ; then
if test "$virtfs" != no ; then
diff --git a/contrib/ivshmem-client/ivshmem-client.c b/contrib/ivshmem-client/ivshmem-client.c
new file mode 100644
index 0000000..11c805c
--- /dev/null
+++ b/contrib/ivshmem-client/ivshmem-client.c
@@ -0,0 +1,433 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include "qemu-common.h"
+#include "qemu/queue.h"
+
+#include "ivshmem-client.h"
+
+/* log a message on stdout if verbose=1 */
+#define IVSHMEM_CLIENT_DEBUG(client, fmt, ...) do { \
+ if ((client)->verbose) { \
+ printf(fmt, ## __VA_ARGS__); \
+ } \
+ } while (0)
+
+/* read message from the unix socket */
+static int
+ivshmem_client_read_one_msg(IvshmemClient *client, long *index, int *fd)
+{
+ int ret;
+ struct msghdr msg;
+ struct iovec iov[1];
+ union {
+ struct cmsghdr cmsg;
+ char control[CMSG_SPACE(sizeof(int))];
+ } msg_control;
+ struct cmsghdr *cmsg;
+
+ iov[0].iov_base = index;
+ iov[0].iov_len = sizeof(*index);
+
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = &msg_control;
+ msg.msg_controllen = sizeof(msg_control);
+
+ ret = recvmsg(client->sock_fd, &msg, 0);
+ if (ret < 0) {
+ IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n",
+ strerror(errno));
+ return -1;
+ }
+ if (ret == 0) {
+ IVSHMEM_CLIENT_DEBUG(client, "lost connection to server\n");
+ return -1;
+ }
+
+ *fd = -1;
+
+ for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+
+ if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
+ cmsg->cmsg_level != SOL_SOCKET ||
+ cmsg->cmsg_type != SCM_RIGHTS) {
+ continue;
+ }
+
+ memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd));
+ }
+
+ return 0;
+}
+
+/* free a peer when the server advertises a disconnection or when the
+ * client is freed */
+static void
+ivshmem_client_free_peer(IvshmemClient *client, IvshmemClientPeer *peer)
+{
+ unsigned vector;
+
+ QTAILQ_REMOVE(&client->peer_list, peer, next);
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ close(peer->vectors[vector]);
+ }
+
+ g_free(peer);
+}
+
+/* handle message coming from server (new peer, new vectors) */
+static int
+ivshmem_client_handle_server_msg(IvshmemClient *client)
+{
+ IvshmemClientPeer *peer;
+ long peer_id;
+ int ret, fd;
+
+ ret = ivshmem_client_read_one_msg(client, &peer_id, &fd);
+ if (ret < 0) {
+ return -1;
+ }
+
+ /* can return a peer or the local client */
+ peer = ivshmem_client_search_peer(client, peer_id);
+
+ /* delete peer */
+ if (fd == -1) {
+
+ if (peer == NULL || peer == &client->local) {
+ IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid "
+ "peer %ld\n", peer_id);
+ return -1;
+ }
+
+ IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %ld\n", peer_id);
+ ivshmem_client_free_peer(client, peer);
+ return 0;
+ }
+
+ /* new peer */
+ if (peer == NULL) {
+ peer = g_malloc0(sizeof(*peer));
+ peer->id = peer_id;
+ peer->vectors_count = 0;
+ QTAILQ_INSERT_TAIL(&client->peer_list, peer, next);
+ IVSHMEM_CLIENT_DEBUG(client, "new peer id = %ld\n", peer_id);
+ }
+
+ /* new vector */
+ IVSHMEM_CLIENT_DEBUG(client, " new vector %d (fd=%d) for peer id %ld\n",
+ peer->vectors_count, fd, peer->id);
+ peer->vectors[peer->vectors_count] = fd;
+ peer->vectors_count++;
+
+ return 0;
+}
+
+/* init a new ivshmem client */
+int
+ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
+ IvshmemClientNotifCb notif_cb, void *notif_arg,
+ bool verbose)
+{
+ int ret;
+ unsigned i;
+
+ memset(client, 0, sizeof(*client));
+
+ ret = snprintf(client->unix_sock_path, sizeof(client->unix_sock_path),
+ "%s", unix_sock_path);
+
+ if (ret < 0 || ret >= sizeof(client->unix_sock_path)) {
+ IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
+ return -1;
+ }
+
+ for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
+ client->local.vectors[i] = -1;
+ }
+
+ QTAILQ_INIT(&client->peer_list);
+ client->local.id = -1;
+
+ client->notif_cb = notif_cb;
+ client->notif_arg = notif_arg;
+ client->verbose = verbose;
+ client->shm_fd = -1;
+ client->sock_fd = -1;
+
+ return 0;
+}
+
+/* create and connect to the unix socket */
+int
+ivshmem_client_connect(IvshmemClient *client)
+{
+ struct sockaddr_un sun;
+ int fd, ret;
+ long tmp;
+
+ IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n",
+ client->unix_sock_path);
+
+ client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (client->sock_fd < 0) {
+ IVSHMEM_CLIENT_DEBUG(client, "cannot create socket: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ sun.sun_family = AF_UNIX;
+ ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
+ client->unix_sock_path);
+ if (ret < 0 || ret >= sizeof(sun.sun_path)) {
+ IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
+ goto err_close;
+ }
+
+ if (connect(client->sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
+ IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n", sun.sun_path,
+ strerror(errno));
+ goto err_close;
+ }
+
+ /* first, we expect our index + a fd == -1 */
+ if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 ||
+ client->local.id < 0 || fd != -1) {
+ IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
+ goto err_close;
+ }
+ IVSHMEM_CLIENT_DEBUG(client, "our_id=%ld\n", client->local.id);
+
+ /* now, we expect shared mem fd + a -1 index, note that shm fd
+ * is not used */
+ if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
+ tmp != -1 || fd < 0) {
+ if (fd >= 0) {
+ close(fd);
+ }
+ IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
+ goto err_close;
+ }
+ client->shm_fd = fd;
+ IVSHMEM_CLIENT_DEBUG(client, "shm_fd=%d\n", fd);
+
+ return 0;
+
+err_close:
+ close(client->sock_fd);
+ client->sock_fd = -1;
+ return -1;
+}
+
+/* close connection to the server, and free all peer structures */
+void
+ivshmem_client_close(IvshmemClient *client)
+{
+ IvshmemClientPeer *peer;
+ unsigned i;
+
+ IVSHMEM_CLIENT_DEBUG(client, "close client\n");
+
+ while ((peer = QTAILQ_FIRST(&client->peer_list)) != NULL) {
+ ivshmem_client_free_peer(client, peer);
+ }
+
+ close(client->shm_fd);
+ client->shm_fd = -1;
+ close(client->sock_fd);
+ client->sock_fd = -1;
+ client->local.id = -1;
+ for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
+ close(client->local.vectors[i]);
+ client->local.vectors[i] = -1;
+ }
+ client->local.vectors_count = 0;
+}
+
+/* get the fd_set according to the unix socket and peer list */
+void
+ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds, int *maxfd)
+{
+ int fd;
+ unsigned vector;
+
+ FD_SET(client->sock_fd, fds);
+ if (client->sock_fd >= *maxfd) {
+ *maxfd = client->sock_fd + 1;
+ }
+
+ for (vector = 0; vector < client->local.vectors_count; vector++) {
+ fd = client->local.vectors[vector];
+ FD_SET(fd, fds);
+ if (fd >= *maxfd) {
+ *maxfd = fd + 1;
+ }
+ }
+}
+
+/* handle events from eventfd: just print a message on notification */
+static int
+ivshmem_client_handle_event(IvshmemClient *client, const fd_set *cur, int maxfd)
+{
+ IvshmemClientPeer *peer;
+ uint64_t kick;
+ unsigned i;
+ int ret;
+
+ peer = &client->local;
+
+ for (i = 0; i < peer->vectors_count; i++) {
+ if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) {
+ continue;
+ }
+
+ ret = read(peer->vectors[i], &kick, sizeof(kick));
+ if (ret < 0) {
+ return ret;
+ }
+ if (ret != sizeof(kick)) {
+ IVSHMEM_CLIENT_DEBUG(client, "invalid read size = %d\n", ret);
+ errno = EINVAL;
+ return -1;
+ }
+ IVSHMEM_CLIENT_DEBUG(client, "received event on fd %d vector %d: %ld\n",
+ peer->vectors[i], i, kick);
+ if (client->notif_cb != NULL) {
+ client->notif_cb(client, peer, i, client->notif_arg);
+ }
+ }
+
+ return 0;
+}
+
+/* read and handle new messages on the given fd_set */
+int
+ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd)
+{
+ if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) &&
+ ivshmem_client_handle_server_msg(client) < 0 && errno != EINTR) {
+ IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_server_msg() "
+ "failed\n");
+ return -1;
+ } else if (ivshmem_client_handle_event(client, fds, maxfd) < 0 &&
+ errno != EINTR) {
+ IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_event() failed\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+/* send a notification on a vector of a peer */
+int
+ivshmem_client_notify(const IvshmemClient *client,
+ const IvshmemClientPeer *peer, unsigned vector)
+{
+ uint64_t kick;
+ int fd;
+
+ if (vector >= peer->vectors_count) {
+ IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %ld\n", vector,
+ peer->id);
+ return -1;
+ }
+ fd = peer->vectors[vector];
+ IVSHMEM_CLIENT_DEBUG(client, "notify peer %ld on vector %d, fd %d\n",
+ peer->id, vector, fd);
+
+ kick = 1;
+ if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) {
+ fprintf(stderr, "could not write to %d: %s\n", peer->vectors[vector],
+ strerror(errno));
+ return -1;
+ }
+ return 0;
+}
+
+/* send a notification to all vectors of a peer */
+int
+ivshmem_client_notify_all_vects(const IvshmemClient *client,
+ const IvshmemClientPeer *peer)
+{
+ unsigned vector;
+ int ret = 0;
+
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ if (ivshmem_client_notify(client, peer, vector) < 0) {
+ ret = -1;
+ }
+ }
+
+ return ret;
+}
+
+/* send a notification to all peers */
+int
+ivshmem_client_notify_broadcast(const IvshmemClient *client)
+{
+ IvshmemClientPeer *peer;
+ int ret = 0;
+
+ QTAILQ_FOREACH(peer, &client->peer_list, next) {
+ if (ivshmem_client_notify_all_vects(client, peer) < 0) {
+ ret = -1;
+ }
+ }
+
+ return ret;
+}
+
+/* lookup peer from its id */
+IvshmemClientPeer *
+ivshmem_client_search_peer(IvshmemClient *client, long peer_id)
+{
+ IvshmemClientPeer *peer;
+
+ if (peer_id == client->local.id) {
+ return &client->local;
+ }
+
+ QTAILQ_FOREACH(peer, &client->peer_list, next) {
+ if (peer->id == peer_id) {
+ return peer;
+ }
+ }
+ return NULL;
+}
+
+/* dump our info, the list of peers their vectors on stdout */
+void
+ivshmem_client_dump(const IvshmemClient *client)
+{
+ const IvshmemClientPeer *peer;
+ unsigned vector;
+
+ /* dump local infos */
+ peer = &client->local;
+ printf("our_id = %ld\n", peer->id);
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ printf(" vector %d is enabled (fd=%d)\n", vector,
+ peer->vectors[vector]);
+ }
+
+ /* dump peers */
+ QTAILQ_FOREACH(peer, &client->peer_list, next) {
+ printf("peer_id = %ld\n", peer->id);
+
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ printf(" vector %d is enabled (fd=%d)\n", vector,
+ peer->vectors[vector]);
+ }
+ }
+}
diff --git a/contrib/ivshmem-client/ivshmem-client.h b/contrib/ivshmem-client/ivshmem-client.h
new file mode 100644
index 0000000..284c4a3
--- /dev/null
+++ b/contrib/ivshmem-client/ivshmem-client.h
@@ -0,0 +1,212 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#ifndef _IVSHMEM_CLIENT_H_
+#define _IVSHMEM_CLIENT_H_
+
+/**
+ * This file provides helper to implement an ivshmem client. It is used
+ * on the host to ask QEMU to send an interrupt to an ivshmem PCI device in a
+ * guest. QEMU also implements an ivshmem client similar to this one, they both
+ * connect to an ivshmem server.
+ *
+ * A standalone ivshmem client based on this file is provided for debug/test
+ * purposes.
+ */
+
+#include <limits.h>
+#include <sys/select.h>
+
+#include "qemu/queue.h"
+
+/**
+ * Maximum number of notification vectors supported by the client
+ */
+#define IVSHMEM_CLIENT_MAX_VECTORS 64
+
+/**
+ * Structure storing a peer
+ *
+ * Each time a client connects to an ivshmem server, it is advertised to
+ * all connected clients through the unix socket. When our ivshmem
+ * client receives a notification, it creates a IvshmemClientPeer
+ * structure to store the infos of this peer.
+ *
+ * This structure is also used to store the information of our own
+ * client in (IvshmemClient)->local.
+ */
+typedef struct IvshmemClientPeer {
+ QTAILQ_ENTRY(IvshmemClientPeer) next; /**< next in list*/
+ long id; /**< the id of the peer */
+ int vectors[IVSHMEM_CLIENT_MAX_VECTORS]; /**< one fd per vector */
+ unsigned vectors_count; /**< number of vectors */
+} IvshmemClientPeer;
+QTAILQ_HEAD(IvshmemClientPeerList, IvshmemClientPeer);
+
+typedef struct IvshmemClientPeerList IvshmemClientPeerList;
+typedef struct IvshmemClient IvshmemClient;
+
+/**
+ * Typedef of callback function used when our IvshmemClient receives a
+ * notification from a peer.
+ */
+typedef void (*IvshmemClientNotifCb)(
+ const IvshmemClient *client,
+ const IvshmemClientPeer *peer,
+ unsigned vect, void *arg);
+
+/**
+ * Structure describing an ivshmem client
+ *
+ * This structure stores all information related to our client: the name
+ * of the server unix socket, the list of peers advertised by the
+ * server, our own client information, and a pointer the notification
+ * callback function used when we receive a notification from a peer.
+ */
+struct IvshmemClient {
+ char unix_sock_path[PATH_MAX]; /**< path to unix sock */
+ int sock_fd; /**< unix sock filedesc */
+ int shm_fd; /**< shm file descriptor */
+
+ IvshmemClientPeerList peer_list; /**< list of peers */
+ IvshmemClientPeer local; /**< our own infos */
+
+ IvshmemClientNotifCb notif_cb; /**< notification callback */
+ void *notif_arg; /**< notification argument */
+
+ bool verbose; /**< true to enable debug */
+};
+
+/**
+ * Initialize an ivshmem client
+ *
+ * @client: A pointer to an uninitialized IvshmemClient structure
+ * @unix_sock_path: The pointer to the unix socket file name
+ * @notif_cb: If not NULL, the pointer to the function to be called when
+ * our IvshmemClient receives a notification from a peer
+ * @notif_arg: Opaque pointer given as-is to the notification callback
+ * function
+ * @verbose: True to enable debug
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
+ IvshmemClientNotifCb notif_cb, void *notif_arg,
+ bool verbose);
+
+/**
+ * Connect to the server
+ *
+ * Connect to the server unix socket, and read the first initial
+ * messages sent by the server, giving the ID of the client and the file
+ * descriptor of the shared memory.
+ *
+ * @client: The ivshmem client
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int ivshmem_client_connect(IvshmemClient *client);
+
+/**
+ * Close connection to the server and free all peer structures
+ *
+ * @client: The ivshmem client
+ */
+void ivshmem_client_close(IvshmemClient *client);
+
+/**
+ * Fill a fd_set with file descriptors to be monitored
+ *
+ * This function will fill a fd_set with all file descriptors
+ * that must be polled (unix server socket and peers eventfd). The
+ * function will not initialize the fd_set, it is up to the caller
+ * to do this.
+ *
+ * @client: The ivshmem client
+ * @fds: The fd_set to be updated
+ * @maxfd: Must be set to the max file descriptor + 1 in fd_set. This value is
+ * updated if this function adds a greater fd in fd_set.
+ */
+void ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds,
+ int *maxfd);
+
+/**
+ * Read and handle new messages
+ *
+ * Given a fd_set filled by select(), handle incoming messages from
+ * server or peers.
+ *
+ * @client: The ivshmem client
+ * @fds: The fd_set containing the file descriptors to be checked. Note
+ * that file descriptors that are not related to our client are
+ * ignored.
+ * @maxfd: The maximum fd in fd_set, plus one.
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd);
+
+/**
+ * Send a notification to a vector of a peer
+ *
+ * @client: The ivshmem client
+ * @peer: The peer to be notified
+ * @vector: The number of the vector
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int ivshmem_client_notify(const IvshmemClient *client,
+ const IvshmemClientPeer *peer, unsigned vector);
+
+/**
+ * Send a notification to all vectors of a peer
+ *
+ * @client: The ivshmem client
+ * @peer: The peer to be notified
+ *
+ * Returns: 0 on success, or a negative value on error (at least one
+ * notification failed)
+ */
+int ivshmem_client_notify_all_vects(const IvshmemClient *client,
+ const IvshmemClientPeer *peer);
+
+/**
+ * Broadcat a notification to all vectors of all peers
+ *
+ * @client: The ivshmem client
+ *
+ * Returns: 0 on success, or a negative value on error (at least one
+ * notification failed)
+ */
+int ivshmem_client_notify_broadcast(const IvshmemClient *client);
+
+/**
+ * Search a peer from its identifier
+ *
+ * Return the peer structure from its peer_id. If the given peer_id is
+ * the local id, the function returns the local peer structure.
+ *
+ * @client: The ivshmem client
+ * @peer_id: The identifier of the peer structure
+ *
+ * Returns: The peer structure, or NULL if not found
+ */
+IvshmemClientPeer *
+ivshmem_client_search_peer(IvshmemClient *client, long peer_id);
+
+/**
+ * Dump information of this ivshmem client on stdout
+ *
+ * Dump the id and the vectors of the given ivshmem client and the list
+ * of its peers and their vectors on stdout.
+ *
+ * @client: The ivshmem client
+ */
+void ivshmem_client_dump(const IvshmemClient *client);
+
+#endif /* _IVSHMEM_CLIENT_H_ */
diff --git a/contrib/ivshmem-client/main.c b/contrib/ivshmem-client/main.c
new file mode 100644
index 0000000..08107ea
--- /dev/null
+++ b/contrib/ivshmem-client/main.c
@@ -0,0 +1,239 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu-common.h"
+
+#include "ivshmem-client.h"
+
+#define IVSHMEM_CLIENT_DEFAULT_VERBOSE 0
+#define IVSHMEM_CLIENT_DEFAULT_UNIX_SOCK_PATH "/tmp/ivshmem_socket"
+
+typedef struct IvshmemClientArgs {
+ bool verbose;
+ const char *unix_sock_path;
+} IvshmemClientArgs;
+
+/* show ivshmem_client_usage and exit with given error code */
+static void
+ivshmem_client_usage(const char *name, int code)
+{
+ fprintf(stderr, "%s [opts]\n", name);
+ fprintf(stderr, " -h: show this help\n");
+ fprintf(stderr, " -v: verbose mode\n");
+ fprintf(stderr, " -S <unix_sock_path>: path to the unix socket\n"
+ " to listen to.\n"
+ " default=%s\n", IVSHMEM_CLIENT_DEFAULT_UNIX_SOCK_PATH);
+ exit(code);
+}
+
+/* parse the program arguments, exit on error */
+static void
+ivshmem_client_parse_args(IvshmemClientArgs *args, int argc, char *argv[])
+{
+ char c;
+
+ while ((c = getopt(argc, argv,
+ "h" /* help */
+ "v" /* verbose */
+ "S:" /* unix_sock_path */
+ )) != -1) {
+
+ switch (c) {
+ case 'h': /* help */
+ ivshmem_client_usage(argv[0], 0);
+ break;
+
+ case 'v': /* verbose */
+ args->verbose = 1;
+ break;
+
+ case 'S': /* unix_sock_path */
+ args->unix_sock_path = strdup(optarg);
+ break;
+
+ default:
+ ivshmem_client_usage(argv[0], 1);
+ break;
+ }
+ }
+}
+
+/* show command line help */
+static void
+ivshmem_client_cmdline_help(void)
+{
+ printf("dump: dump peers (including us)\n"
+ "int <peer> <vector>: notify one vector on a peer\n"
+ "int <peer> all: notify all vectors of a peer\n"
+ "int all: notify all vectors of all peers (excepting us)\n");
+}
+
+/* read stdin and handle commands */
+static int
+ivshmem_client_handle_stdin_command(IvshmemClient *client)
+{
+ IvshmemClientPeer *peer;
+ char buf[128];
+ char *s, *token;
+ int ret;
+ int peer_id, vector;
+
+ memset(buf, 0, sizeof(buf));
+ ret = read(0, buf, sizeof(buf) - 1);
+ if (ret < 0) {
+ return -1;
+ }
+
+ s = buf;
+ while ((token = strsep(&s, "\n\r;")) != NULL) {
+ if (!strcmp(token, "")) {
+ continue;
+ }
+ if (!strcmp(token, "?")) {
+ ivshmem_client_cmdline_help();
+ }
+ if (!strcmp(token, "help")) {
+ ivshmem_client_cmdline_help();
+ } else if (!strcmp(token, "dump")) {
+ ivshmem_client_dump(client);
+ } else if (!strcmp(token, "int all")) {
+ ivshmem_client_notify_broadcast(client);
+ } else if (sscanf(token, "int %d %d", &peer_id, &vector) == 2) {
+ peer = ivshmem_client_search_peer(client, peer_id);
+ if (peer == NULL) {
+ printf("cannot find peer_id = %d\n", peer_id);
+ continue;
+ }
+ ivshmem_client_notify(client, peer, vector);
+ } else if (sscanf(token, "int %d all", &peer_id) == 1) {
+ peer = ivshmem_client_search_peer(client, peer_id);
+ if (peer == NULL) {
+ printf("cannot find peer_id = %d\n", peer_id);
+ continue;
+ }
+ ivshmem_client_notify_all_vects(client, peer);
+ } else {
+ printf("invalid command, type help\n");
+ }
+ }
+
+ printf("cmd> ");
+ fflush(stdout);
+ return 0;
+}
+
+/* listen on stdin (command line), on unix socket (notifications of new
+ * and dead peers), and on eventfd (IRQ request) */
+static int
+ivshmem_client_poll_events(IvshmemClient *client)
+{
+ fd_set fds;
+ int ret, maxfd;
+
+ while (1) {
+
+ FD_ZERO(&fds);
+ FD_SET(0, &fds); /* add stdin in fd_set */
+ maxfd = 1;
+
+ ivshmem_client_get_fds(client, &fds, &maxfd);
+
+ ret = select(maxfd, &fds, NULL, NULL, NULL);
+ if (ret < 0) {
+ if (errno == EINTR) {
+ continue;
+ }
+
+ fprintf(stderr, "select error: %s\n", strerror(errno));
+ break;
+ }
+ if (ret == 0) {
+ continue;
+ }
+
+ if (FD_ISSET(0, &fds) &&
+ ivshmem_client_handle_stdin_command(client) < 0 && errno != EINTR) {
+ fprintf(stderr, "ivshmem_client_handle_stdin_command() failed\n");
+ break;
+ }
+
+ if (ivshmem_client_handle_fds(client, &fds, maxfd) < 0) {
+ fprintf(stderr, "ivshmem_client_handle_fds() failed\n");
+ break;
+ }
+ }
+
+ return ret;
+}
+
+/* callback when we receive a notification (just display it) */
+static void
+ivshmem_client_notification_cb(const IvshmemClient *client,
+ const IvshmemClientPeer *peer,
+ unsigned vect, void *arg)
+{
+ (void)client;
+ (void)arg;
+ printf("receive notification from peer_id=%ld vector=%d\n", peer->id, vect);
+}
+
+int
+main(int argc, char *argv[])
+{
+ struct sigaction sa;
+ IvshmemClient client;
+ IvshmemClientArgs args = {
+ .verbose = IVSHMEM_CLIENT_DEFAULT_VERBOSE,
+ .unix_sock_path = IVSHMEM_CLIENT_DEFAULT_UNIX_SOCK_PATH,
+ };
+
+ /* parse arguments, will exit on error */
+ ivshmem_client_parse_args(&args, argc, argv);
+
+ /* Ignore SIGPIPE, see this link for more info:
+ * http://www.mail-archive.com/libevent-users@monkey.org/msg01606.html */
+ sa.sa_handler = SIG_IGN;
+ sa.sa_flags = 0;
+ if (sigemptyset(&sa.sa_mask) == -1 ||
+ sigaction(SIGPIPE, &sa, 0) == -1) {
+ perror("failed to ignore SIGPIPE; sigaction");
+ return 1;
+ }
+
+ ivshmem_client_cmdline_help();
+ printf("cmd> ");
+ fflush(stdout);
+
+ if (ivshmem_client_init(&client, args.unix_sock_path,
+ ivshmem_client_notification_cb, NULL,
+ args.verbose) < 0) {
+ fprintf(stderr, "cannot init client\n");
+ return 1;
+ }
+
+ while (1) {
+ if (ivshmem_client_connect(&client) < 0) {
+ fprintf(stderr, "cannot connect to server, retry in 1 second\n");
+ sleep(1);
+ continue;
+ }
+
+ fprintf(stdout, "listen on server socket %d\n", client.sock_fd);
+
+ if (ivshmem_client_poll_events(&client) == 0) {
+ continue;
+ }
+
+ /* disconnected from server, reset all peers */
+ fprintf(stdout, "disconnected from server\n");
+
+ ivshmem_client_close(&client);
+ }
+
+ return 0;
+}
diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
new file mode 100644
index 0000000..91dc208
--- /dev/null
+++ b/contrib/ivshmem-server/ivshmem-server.c
@@ -0,0 +1,417 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/eventfd.h>
+
+#include "qemu-common.h"
+#include "qemu/queue.h"
+
+#include "ivshmem-server.h"
+
+/* log a message on stdout if verbose=1 */
+#define IVSHMEM_SERVER_DEBUG(server, fmt, ...) do { \
+ if ((server)->verbose) { \
+ printf(fmt, ## __VA_ARGS__); \
+ } \
+ } while (0)
+
+/** maximum size of a huge page, used by ivshmem_server_ftruncate() */
+#define IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE (1024 * 1024 * 1024)
+
+/** default listen backlog (number of sockets not accepted) */
+#define IVSHMEM_SERVER_LISTEN_BACKLOG 10
+
+/* send message to a client unix socket */
+static int
+ivshmem_server_send_one_msg(int sock_fd, long peer_id, int fd)
+{
+ int ret;
+ struct msghdr msg;
+ struct iovec iov[1];
+ union {
+ struct cmsghdr cmsg;
+ char control[CMSG_SPACE(sizeof(int))];
+ } msg_control;
+ struct cmsghdr *cmsg;
+
+ iov[0].iov_base = &peer_id;
+ iov[0].iov_len = sizeof(peer_id);
+
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ /* if fd is specified, add it in a cmsg */
+ if (fd >= 0) {
+ msg.msg_control = &msg_control;
+ msg.msg_controllen = sizeof(msg_control);
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
+ }
+
+ ret = sendmsg(sock_fd, &msg, 0);
+ if (ret <= 0) {
+ return -1;
+ }
+
+ return 0;
+}
+
+/* free a peer when the server advertises a disconnection or when the
+ * server is freed */
+static void
+ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
+{
+ unsigned vector;
+ IvshmemServerPeer *other_peer;
+
+ IVSHMEM_SERVER_DEBUG(server, "free peer %ld\n", peer->id);
+ close(peer->sock_fd);
+ QTAILQ_REMOVE(&server->peer_list, peer, next);
+
+ /* advertise the deletion to other peers */
+ QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
+ ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id, -1);
+ }
+
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ close(peer->vectors[vector]);
+ }
+
+ g_free(peer);
+}
+
+/* send the peer id and the shm_fd just after a new client connection */
+static int
+ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
+{
+ int ret;
+
+ /* send the peer id to the client */
+ ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
+ if (ret < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send peer id: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ /* send the shm_fd */
+ ret = ivshmem_server_send_one_msg(peer->sock_fd, -1, server->shm_fd);
+ if (ret < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send shm fd: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+/* handle message on listening unix socket (new client connection) */
+static int
+ivshmem_server_handle_new_conn(IvshmemServer *server)
+{
+ IvshmemServerPeer *peer, *other_peer;
+ struct sockaddr_un unaddr;
+ socklen_t unaddr_len;
+ int newfd;
+ unsigned i;
+
+ /* accept the incoming connection */
+ unaddr_len = sizeof(unaddr);
+ newfd = accept4(server->sock_fd, (struct sockaddr *)&unaddr, &unaddr_len,
+ SOCK_NONBLOCK);
+ if (newfd < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot accept() %s\n", strerror(errno));
+ return -1;
+ }
+
+ IVSHMEM_SERVER_DEBUG(server, "accept()=%d\n", newfd);
+
+ /* allocate new structure for this peer */
+ peer = g_malloc0(sizeof(*peer));
+ peer->sock_fd = newfd;
+
+ /* get an unused peer id */
+ while (ivshmem_server_search_peer(server, server->cur_id) != NULL) {
+ server->cur_id++;
+ }
+ peer->id = server->cur_id++;
+
+ /* create eventfd, one per vector */
+ peer->vectors_count = server->n_vectors;
+ for (i = 0; i < peer->vectors_count; i++) {
+ peer->vectors[i] = eventfd(0, 0);
+ if (peer->vectors[i] < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot create eventfd\n");
+ goto fail;
+ }
+ }
+
+ /* send peer id and shm fd */
+ if (ivshmem_server_send_initial_info(server, peer) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send initial info\n");
+ goto fail;
+ }
+
+ /* advertise the new peer to others */
+ QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
+ for (i = 0; i < peer->vectors_count; i++) {
+ ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id,
+ peer->vectors[i]);
+ }
+ }
+
+ /* advertise the other peers to the new one */
+ QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
+ for (i = 0; i < peer->vectors_count; i++) {
+ ivshmem_server_send_one_msg(peer->sock_fd, other_peer->id,
+ other_peer->vectors[i]);
+ }
+ }
+
+ /* advertise the new peer to itself */
+ for (i = 0; i < peer->vectors_count; i++) {
+ ivshmem_server_send_one_msg(peer->sock_fd, peer->id, peer->vectors[i]);
+ }
+
+ QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
+ IVSHMEM_SERVER_DEBUG(server, "new peer id = %ld\n", peer->id);
+ return 0;
+
+fail:
+ while (i--) {
+ close(peer->vectors[i]);
+ }
+ close(newfd);
+ g_free(peer);
+ return -1;
+}
+
+/* Try to ftruncate a file to next power of 2 of shmsize.
+ * If it fails; all power of 2 above shmsize are tested until
+ * we reach the maximum huge page size. This is useful
+ * if the shm file is in a hugetlbfs that cannot be truncated to the
+ * shm_size value. */
+static int
+ivshmem_server_ftruncate(int fd, unsigned shmsize)
+{
+ int ret;
+
+ /* align shmsize to next power of 2 */
+ shmsize--;
+ shmsize |= shmsize >> 1;
+ shmsize |= shmsize >> 2;
+ shmsize |= shmsize >> 4;
+ shmsize |= shmsize >> 8;
+ shmsize |= shmsize >> 16;
+ shmsize++;
+
+ while (shmsize <= IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE) {
+ ret = ftruncate(fd, shmsize);
+ if (ret == 0) {
+ return ret;
+ }
+ shmsize *= 2;
+ }
+
+ return -1;
+}
+
+/* Init a new ivshmem server */
+int
+ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
+ const char *shm_path, size_t shm_size, unsigned n_vectors,
+ bool verbose)
+{
+ int ret;
+
+ memset(server, 0, sizeof(*server));
+
+ ret = snprintf(server->unix_sock_path, sizeof(server->unix_sock_path),
+ "%s", unix_sock_path);
+ if (ret < 0 || ret >= sizeof(server->unix_sock_path)) {
+ IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
+ return -1;
+ }
+ ret = snprintf(server->shm_path, sizeof(server->shm_path),
+ "%s", shm_path);
+ if (ret < 0 || ret >= sizeof(server->shm_path)) {
+ IVSHMEM_SERVER_DEBUG(server, "could not copy shm path\n");
+ return -1;
+ }
+
+ server->shm_size = shm_size;
+ server->n_vectors = n_vectors;
+ server->verbose = verbose;
+
+ QTAILQ_INIT(&server->peer_list);
+
+ return 0;
+}
+
+/* open shm, create and bind to the unix socket */
+int
+ivshmem_server_start(IvshmemServer *server)
+{
+ struct sockaddr_un sun;
+ int shm_fd, sock_fd, ret;
+
+ /* open shm file */
+ shm_fd = shm_open(server->shm_path, O_CREAT|O_RDWR, S_IRWXU);
+ if (shm_fd < 0) {
+ fprintf(stderr, "cannot open shm file %s: %s\n", server->shm_path,
+ strerror(errno));
+ return -1;
+ }
+ if (ivshmem_server_ftruncate(shm_fd, server->shm_size) < 0) {
+ fprintf(stderr, "ftruncate(%s) failed: %s\n", server->shm_path,
+ strerror(errno));
+ goto err_close_shm;
+ }
+
+ IVSHMEM_SERVER_DEBUG(server, "create & bind socket %s\n",
+ server->unix_sock_path);
+
+ /* create the unix listening socket */
+ sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (sock_fd < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot create socket: %s\n",
+ strerror(errno));
+ goto err_close_shm;
+ }
+
+ sun.sun_family = AF_UNIX;
+ ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
+ server->unix_sock_path);
+ if (ret < 0 || ret >= sizeof(sun.sun_path)) {
+ IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
+ goto err_close_sock;
+ }
+ if (bind(sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot connect to %s: %s\n", sun.sun_path,
+ strerror(errno));
+ goto err_close_sock;
+ }
+
+ if (listen(sock_fd, IVSHMEM_SERVER_LISTEN_BACKLOG) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "listen() failed: %s\n", strerror(errno));
+ goto err_close_sock;
+ }
+
+ server->sock_fd = sock_fd;
+ server->shm_fd = shm_fd;
+
+ return 0;
+
+err_close_sock:
+ close(sock_fd);
+err_close_shm:
+ close(shm_fd);
+ return -1;
+}
+
+/* close connections to clients, the unix socket and the shm fd */
+void
+ivshmem_server_close(IvshmemServer *server)
+{
+ IvshmemServerPeer *peer;
+
+ IVSHMEM_SERVER_DEBUG(server, "close server\n");
+
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ ivshmem_server_free_peer(server, peer);
+ }
+
+ unlink(server->unix_sock_path);
+ close(server->sock_fd);
+ close(server->shm_fd);
+ server->sock_fd = -1;
+ server->shm_fd = -1;
+}
+
+/* get the fd_set according to the unix socket and the peer list */
+void
+ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd)
+{
+ IvshmemServerPeer *peer;
+
+ FD_SET(server->sock_fd, fds);
+ if (server->sock_fd >= *maxfd) {
+ *maxfd = server->sock_fd + 1;
+ }
+
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ FD_SET(peer->sock_fd, fds);
+ if (peer->sock_fd >= *maxfd) {
+ *maxfd = peer->sock_fd + 1;
+ }
+ }
+}
+
+/* process incoming messages on the sockets in fd_set */
+int
+ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
+{
+ IvshmemServerPeer *peer, *peer_next;
+
+ if (server->sock_fd < maxfd && FD_ISSET(server->sock_fd, fds) &&
+ ivshmem_server_handle_new_conn(server) < 0 && errno != EINTR) {
+ IVSHMEM_SERVER_DEBUG(server, "ivshmem_server_handle_new_conn() "
+ "failed\n");
+ return -1;
+ }
+
+ QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, peer_next) {
+ /* any message from a peer socket result in a close() */
+ IVSHMEM_SERVER_DEBUG(server, "peer->sock_fd=%d\n", peer->sock_fd);
+ if (peer->sock_fd < maxfd && FD_ISSET(peer->sock_fd, fds)) {
+ ivshmem_server_free_peer(server, peer);
+ }
+ }
+
+ return 0;
+}
+
+/* lookup peer from its id */
+IvshmemServerPeer *
+ivshmem_server_search_peer(IvshmemServer *server, long peer_id)
+{
+ IvshmemServerPeer *peer;
+
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ if (peer->id == peer_id) {
+ return peer;
+ }
+ }
+ return NULL;
+}
+
+/* dump our info, the list of peers their vectors on stdout */
+void
+ivshmem_server_dump(const IvshmemServer *server)
+{
+ const IvshmemServerPeer *peer;
+ unsigned vector;
+
+ /* dump peers */
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ printf("peer_id = %ld\n", peer->id);
+
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ printf(" vector %d is enabled (fd=%d)\n", vector,
+ peer->vectors[vector]);
+ }
+ }
+}
diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h
new file mode 100644
index 0000000..f85dcd2
--- /dev/null
+++ b/contrib/ivshmem-server/ivshmem-server.h
@@ -0,0 +1,164 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#ifndef _IVSHMEM_SERVER_H_
+#define _IVSHMEM_SERVER_H_
+
+/**
+ * The ivshmem server is a daemon that creates a unix socket in listen
+ * mode. The ivshmem clients (qemu or ivshmem-client) connect to this
+ * unix socket. For each client, the server will create some eventfd
+ * (see EVENTFD(2)), one per vector. These fd are transmitted to all
+ * clients using the SCM_RIGHTS cmsg message. Therefore, each client is
+ * able to send a notification to another client without beeing
+ * "profixied" by the server.
+ *
+ * We use this mechanism to send interruptions between guests.
+ * qemu is able to transform an event on a eventfd into a PCI MSI-x
+ * interruption in the guest.
+ *
+ * The ivshmem server is also able to share the file descriptor
+ * associated to the ivshmem shared memory.
+ */
+
+#include <limits.h>
+#include <sys/select.h>
+
+#include "qemu/queue.h"
+
+/**
+ * Maximum number of notification vectors supported by the server
+ */
+#define IVSHMEM_SERVER_MAX_VECTORS 64
+
+/**
+ * Structure storing a peer
+ *
+ * Each time a client connects to an ivshmem server, a new
+ * IvshmemServerPeer structure is created. This peer and all its
+ * vectors are advertised to all connected clients through the connected
+ * unix sockets.
+ */
+typedef struct IvshmemServerPeer {
+ QTAILQ_ENTRY(IvshmemServerPeer) next; /**< next in list*/
+ int sock_fd; /**< connected unix sock */
+ long id; /**< the id of the peer */
+ int vectors[IVSHMEM_SERVER_MAX_VECTORS]; /**< one fd per vector */
+ unsigned vectors_count; /**< number of vectors */
+} IvshmemServerPeer;
+QTAILQ_HEAD(IvshmemServerPeerList, IvshmemServerPeer);
+
+typedef struct IvshmemServerPeerList IvshmemServerPeerList;
+
+/**
+ * Structure describing an ivshmem server
+ *
+ * This structure stores all information related to our server: the name
+ * of the server unix socket and the list of connected peers.
+ */
+typedef struct IvshmemServer {
+ char unix_sock_path[PATH_MAX]; /**< path to unix socket */
+ int sock_fd; /**< unix sock file descriptor */
+ char shm_path[PATH_MAX]; /**< path to shm */
+ size_t shm_size; /**< size of shm */
+ int shm_fd; /**< shm file descriptor */
+ unsigned n_vectors; /**< number of vectors */
+ long cur_id; /**< id to be given to next client */
+ bool verbose; /**< true in verbose mode */
+ IvshmemServerPeerList peer_list; /**< list of peers */
+} IvshmemServer;
+
+/**
+ * Initialize an ivshmem server
+ *
+ * @server: A pointer to an uninitialized IvshmemServer structure
+ * @unix_sock_path: The pointer to the unix socket file name
+ * @shm_path: Path to the shared memory. The path corresponds to a POSIX
+ * shm name. To use a real file, for instance in a hugetlbfs,
+ * it is possible to use /../../abspath/to/file.
+ * @shm_size: Size of shared memory
+ * @n_vectors: Number of interrupt vectors per client
+ * @verbose: True to enable verbose mode
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int
+ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
+ const char *shm_path, size_t shm_size, unsigned n_vectors,
+ bool verbose);
+
+/**
+ * Open the shm, then create and bind to the unix socket
+ *
+ * @server: The pointer to the initialized IvshmemServer structure
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int ivshmem_server_start(IvshmemServer *server);
+
+/**
+ * Close the server
+ *
+ * Close connections to all clients, close the unix socket and the
+ * shared memory file descriptor. The structure remains initialized, so
+ * it is possible to call ivshmem_server_start() again after a call to
+ * ivshmem_server_close().
+ *
+ * @server: The ivshmem server
+ */
+void ivshmem_server_close(IvshmemServer *server);
+
+/**
+ * Fill a fd_set with file descriptors to be monitored
+ *
+ * This function will fill a fd_set with all file descriptors that must
+ * be polled (unix server socket and peers unix socket). The function
+ * will not initialize the fd_set, it is up to the caller to do it.
+ *
+ * @server: The ivshmem server
+ * @fds: The fd_set to be updated
+ * @maxfd: Must be set to the max file descriptor + 1 in fd_set. This value is
+ * updated if this function adds a greater fd in fd_set.
+ */
+void
+ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd);
+
+/**
+ * Read and handle new messages
+ *
+ * Given a fd_set (for instance filled by a call to select()), handle
+ * incoming messages from peers.
+ *
+ * @server: The ivshmem server
+ * @fds: The fd_set containing the file descriptors to be checked. Note that
+ * file descriptors that are not related to our server are ignored.
+ * @maxfd: The maximum fd in fd_set, plus one.
+ *
+ * Returns: 0 on success, or a negative value on error
+ */
+int ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd);
+
+/**
+ * Search a peer from its identifier
+ *
+ * @server: The ivshmem server
+ * @peer_id: The identifier of the peer structure
+ *
+ * Returns: The peer structure, or NULL if not found
+ */
+IvshmemServerPeer *
+ivshmem_server_search_peer(IvshmemServer *server, long peer_id);
+
+/**
+ * Dump information of this ivshmem server and its peers on stdout
+ *
+ * @server: The ivshmem server
+ */
+void ivshmem_server_dump(const IvshmemServer *server);
+
+#endif /* _IVSHMEM_SERVER_H_ */
diff --git a/contrib/ivshmem-server/main.c b/contrib/ivshmem-server/main.c
new file mode 100644
index 0000000..67b3d61
--- /dev/null
+++ b/contrib/ivshmem-server/main.c
@@ -0,0 +1,264 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu-common.h"
+
+#include "ivshmem-server.h"
+
+#define IVSHMEM_SERVER_DEFAULT_VERBOSE 0
+#define IVSHMEM_SERVER_DEFAULT_FOREGROUND 0
+#define IVSHMEM_SERVER_DEFAULT_PID_FILE "/var/run/ivshmem-server.pid"
+#define IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH "/tmp/ivshmem_socket"
+#define IVSHMEM_SERVER_DEFAULT_SHM_PATH "ivshmem"
+#define IVSHMEM_SERVER_DEFAULT_SHM_SIZE (4*1024*1024)
+#define IVSHMEM_SERVER_DEFAULT_N_VECTORS 1
+
+/* used to quit on signal SIGTERM */
+static int ivshmem_server_quit;
+
+/* arguments given by the user */
+typedef struct IvshmemServerArgs {
+ bool verbose;
+ bool foreground;
+ const char *pid_file;
+ const char *unix_socket_path;
+ const char *shm_path;
+ size_t shm_size;
+ unsigned n_vectors;
+} IvshmemServerArgs;
+
+/* show ivshmem_server_usage and exit with given error code */
+static void
+ivshmem_server_usage(const char *name, int code)
+{
+ fprintf(stderr, "%s [opts]\n", name);
+ fprintf(stderr, " -h: show this help\n");
+ fprintf(stderr, " -v: verbose mode\n");
+ fprintf(stderr, " -F: foreground mode (default is to daemonize)\n");
+ fprintf(stderr, " -p <pid_file>: path to the PID file (used in daemon\n"
+ " mode only).\n"
+ " Default=%s\n", IVSHMEM_SERVER_DEFAULT_SHM_PATH);
+ fprintf(stderr, " -S <unix_socket_path>: path to the unix socket\n"
+ " to listen to.\n"
+ " Default=%s\n", IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH);
+ fprintf(stderr, " -m <shm_path>: path to the shared memory.\n"
+ " The path corresponds to a POSIX shm name. To use a\n"
+ " real file, for instance in a hugetlbfs, use\n"
+ " /../../abspath/to/file.\n"
+ " default=%s\n", IVSHMEM_SERVER_DEFAULT_SHM_PATH);
+ fprintf(stderr, " -l <size>: size of shared memory in bytes. The suffix\n"
+ " K, M and G can be used (ex: 1K means 1024).\n"
+ " default=%u\n", IVSHMEM_SERVER_DEFAULT_SHM_SIZE);
+ fprintf(stderr, " -n <n_vects>: number of vectors.\n"
+ " default=%u\n", IVSHMEM_SERVER_DEFAULT_N_VECTORS);
+
+ exit(code);
+}
+
+/* parse the program arguments, exit on error */
+static void
+ivshmem_server_parse_args(IvshmemServerArgs *args, int argc, char *argv[])
+{
+ char c;
+ unsigned long long v;
+ Error *errp;
+
+ while ((c = getopt(argc, argv,
+ "h" /* help */
+ "v" /* verbose */
+ "F" /* foreground */
+ "p:" /* pid_file */
+ "S:" /* unix_socket_path */
+ "m:" /* shm_path */
+ "l:" /* shm_size */
+ "n:" /* n_vectors */
+ )) != -1) {
+
+ switch (c) {
+ case 'h': /* help */
+ ivshmem_server_usage(argv[0], 0);
+ break;
+
+ case 'v': /* verbose */
+ args->verbose = 1;
+ break;
+
+ case 'F': /* foreground */
+ args->foreground = 1;
+ break;
+
+ case 'p': /* pid_file */
+ args->pid_file = strdup(optarg);
+ break;
+
+ case 'S': /* unix_socket_path */
+ args->unix_socket_path = strdup(optarg);
+ break;
+
+ case 'm': /* shm_path */
+ args->shm_path = strdup(optarg);
+ break;
+
+ case 'l': /* shm_size */
+ parse_option_size("shm_size", optarg, &args->shm_size, &errp);
+ if (errp) {
+ fprintf(stderr, "cannot parse shm size: %s\n",
+ error_get_pretty(errp));
+ error_free(errp);
+ ivshmem_server_usage(argv[0], 1);
+ }
+ break;
+
+ case 'n': /* n_vectors */
+ if (parse_uint_full(optarg, &v, 0) < 0) {
+ fprintf(stderr, "cannot parse n_vectors\n");
+ ivshmem_server_usage(argv[0], 1);
+ }
+ args->n_vectors = v;
+ break;
+
+ default:
+ ivshmem_server_usage(argv[0], 1);
+ break;
+ }
+ }
+
+ if (args->n_vectors > IVSHMEM_SERVER_MAX_VECTORS) {
+ fprintf(stderr, "too many requested vectors (max is %d)\n",
+ IVSHMEM_SERVER_MAX_VECTORS);
+ ivshmem_server_usage(argv[0], 1);
+ }
+
+ if (args->verbose == 1 && args->foreground == 0) {
+ fprintf(stderr, "cannot use verbose in daemon mode\n");
+ ivshmem_server_usage(argv[0], 1);
+ }
+}
+
+/* wait for events on listening server unix socket and connected client
+ * sockets */
+static int
+ivshmem_server_poll_events(IvshmemServer *server)
+{
+ fd_set fds;
+ int ret = 0, maxfd;
+
+ while (!ivshmem_server_quit) {
+
+ FD_ZERO(&fds);
+ maxfd = 0;
+ ivshmem_server_get_fds(server, &fds, &maxfd);
+
+ ret = select(maxfd, &fds, NULL, NULL, NULL);
+
+ if (ret < 0) {
+ if (errno == EINTR) {
+ continue;
+ }
+
+ fprintf(stderr, "select error: %s\n", strerror(errno));
+ break;
+ }
+ if (ret == 0) {
+ continue;
+ }
+
+ if (ivshmem_server_handle_fds(server, &fds, maxfd) < 0) {
+ fprintf(stderr, "ivshmem_server_handle_fds() failed\n");
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static void
+ivshmem_server_quit_cb(int signum)
+{
+ ivshmem_server_quit = 1;
+}
+
+int
+main(int argc, char *argv[])
+{
+ IvshmemServer server;
+ struct sigaction sa, sa_quit;
+ IvshmemServerArgs args = {
+ .verbose = IVSHMEM_SERVER_DEFAULT_VERBOSE,
+ .foreground = IVSHMEM_SERVER_DEFAULT_FOREGROUND,
+ .pid_file = IVSHMEM_SERVER_DEFAULT_PID_FILE,
+ .unix_socket_path = IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH,
+ .shm_path = IVSHMEM_SERVER_DEFAULT_SHM_PATH,
+ .shm_size = IVSHMEM_SERVER_DEFAULT_SHM_SIZE,
+ .n_vectors = IVSHMEM_SERVER_DEFAULT_N_VECTORS,
+ };
+ int ret = 1;
+
+ /* parse arguments, will exit on error */
+ ivshmem_server_parse_args(&args, argc, argv);
+
+ /* Ignore SIGPIPE, see this link for more info:
+ * http://www.mail-archive.com/libevent-users@monkey.org/msg01606.html */
+ sa.sa_handler = SIG_IGN;
+ sa.sa_flags = 0;
+ if (sigemptyset(&sa.sa_mask) == -1 ||
+ sigaction(SIGPIPE, &sa, 0) == -1) {
+ perror("failed to ignore SIGPIPE; sigaction");
+ goto err;
+ }
+
+ sa_quit.sa_handler = ivshmem_server_quit_cb;
+ sa_quit.sa_flags = 0;
+ if (sigemptyset(&sa_quit.sa_mask) == -1 ||
+ sigaction(SIGTERM, &sa_quit, 0) == -1) {
+ perror("failed to add SIGTERM handler; sigaction");
+ goto err;
+ }
+
+ /* init the ivshms structure */
+ if (ivshmem_server_init(&server, args.unix_socket_path, args.shm_path,
+ args.shm_size, args.n_vectors, args.verbose) < 0) {
+ fprintf(stderr, "cannot init server\n");
+ goto err;
+ }
+
+ /* start the ivshmem server (open shm & unix socket) */
+ if (ivshmem_server_start(&server) < 0) {
+ fprintf(stderr, "cannot bind\n");
+ goto err;
+ }
+
+ /* daemonize if asked to */
+ if (!args.foreground) {
+ FILE *fp;
+
+ if (daemon(1, 1) < 0) {
+ fprintf(stderr, "cannot daemonize: %s\n", strerror(errno));
+ goto err_close;
+ }
+
+ /* write pid file */
+ fp = fopen(args.pid_file, "w");
+ if (fp == NULL) {
+ fprintf(stderr, "cannot write pid file: %s\n", strerror(errno));
+ goto err_close;
+ }
+
+ fprintf(fp, "%d\n", (int) getpid());
+ fclose(fp);
+ }
+
+ ivshmem_server_poll_events(&server);
+ fprintf(stdout, "server disconnected\n");
+ ret = 0;
+
+err_close:
+ ivshmem_server_close(&server);
+err:
+ return ret;
+}
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 2b232ae..380d573 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -1250,9 +1250,13 @@ is qemu.git/contrib/ivshmem-server. An example syntax when using the shared
memory server is:
@example
-qemu-system-i386 -device ivshmem,size=<size in format accepted by -m>[,chardev=<id>]
- [,msi=on][,ioeventfd=on][,vectors=n][,role=peer|master]
-qemu-system-i386 -chardev socket,path=<path>,id=<id>
+# First start the ivshmem server once and for all
+ivshmem-server -p <pidfile> -S <path> -m <shm name> -l <shm size> -n <vectors n>
+
+# Then start your qemu instances with matching arguments
+qemu-system-i386 -device ivshmem,size=<shm size>,vectors=<vectors n>,chardev=<id>
+ [,msi=on][,ioeventfd=on][,role=peer|master]
+ -chardev socket,path=<path>,id=<id>
@end example
When using the server, the guest will be assigned a VM ID (>=0) that allows guests
--
1.7.10.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH v6 2/3] docs: update ivshmem device spec
2014-09-08 9:17 [Qemu-devel] [PATCH v6 0/3] ivshmem: update documentation, add client/server tools David Marchand
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server David Marchand
@ 2014-09-08 9:17 ` David Marchand
2014-09-08 10:01 ` Michael S. Tsirkin
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU David Marchand
2 siblings, 1 reply; 9+ messages in thread
From: David Marchand @ 2014-09-08 9:17 UTC (permalink / raw)
To: qemu-devel
Cc: kvm, mst, stefanha, claudio.fontana, armbru, arei.gonglei,
mkletzan, pbonzini, jani.kokkonen, cam
Add some notes on the parts needed to use ivshmem devices: more specifically,
explain the purpose of an ivshmem server and the basic concept to use the
ivshmem devices in guests.
Move some parts of the documentation and re-organise it.
Signed-off-by: David Marchand <david.marchand@6wind.com>
Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
docs/specs/ivshmem_device_spec.txt | 124 +++++++++++++++++++++++++++---------
1 file changed, 93 insertions(+), 31 deletions(-)
diff --git a/docs/specs/ivshmem_device_spec.txt b/docs/specs/ivshmem_device_spec.txt
index 667a862..12f338e 100644
--- a/docs/specs/ivshmem_device_spec.txt
+++ b/docs/specs/ivshmem_device_spec.txt
@@ -2,30 +2,103 @@
Device Specification for Inter-VM shared memory device
------------------------------------------------------
-The Inter-VM shared memory device is designed to share a region of memory to
-userspace in multiple virtual guests. The memory region does not belong to any
-guest, but is a POSIX memory object on the host. Optionally, the device may
-support sending interrupts to other guests sharing the same memory region.
+The Inter-VM shared memory device is designed to share a memory region (created
+on the host via the POSIX shared memory API) between multiple QEMU processes
+running different guests. In order for all guests to be able to pick up the
+shared memory area, it is modeled by QEMU as a PCI device exposing said memory
+to the guest as a PCI BAR.
+The memory region does not belong to any guest, but is a POSIX memory object on
+the host. The host can access this shared memory if needed.
+
+The device also provides an optional communication mechanism between guests
+sharing the same memory object. More details about that in the section 'Guest to
+guest communication' section.
The Inter-VM PCI device
-----------------------
-*BARs*
+From the VM point of view, the ivshmem PCI device supports three BARs.
+
+- BAR0 is a 1 Kbyte MMIO region to support registers and interrupts when MSI is
+ not used.
+- BAR1 is used for MSI-X when it is enabled in the device.
+- BAR2 is used to access the shared memory object.
+
+It is your choice how to use the device but you must choose between two
+behaviors :
+
+- basically, if you only need the shared memory part, you will map BAR2.
+ This way, you have access to the shared memory in guest and can use it as you
+ see fit (memnic, for example, uses it in userland
+ http://dpdk.org/browse/memnic).
+
+- BAR0 and BAR1 are used to implement an optional communication mechanism
+ through interrupts in the guests. If you need an event mechanism between the
+ guests accessing the shared memory, you will most likely want to write a
+ kernel driver that will handle interrupts. See details in the section 'Guest
+ to guest communication' section.
+
+The behavior is chosen when starting your QEMU processes:
+- no communication mechanism needed, the first QEMU to start creates the shared
+ memory on the host, subsequent QEMU processes will use it.
+
+- communication mechanism needed, an ivshmem server must be started before any
+ QEMU processes, then each QEMU process connects to the server unix socket.
+
+For more details on the QEMU ivshmem parameters, see qemu-doc documentation.
+
+
+Guest to guest communication
+----------------------------
+
+This section details the communication mechanism between the guests accessing
+the ivhsmem shared memory.
-The device supports three BARs. BAR0 is a 1 Kbyte MMIO region to support
-registers. BAR1 is used for MSI-X when it is enabled in the device. BAR2 is
-used to map the shared memory object from the host. The size of BAR2 is
-specified when the guest is started and must be a power of 2 in size.
+*ivshmem server*
-*Registers*
+This server code is available in qemu.git/contrib/ivshmem-server.
-The device currently supports 4 registers of 32-bits each. Registers
-are used for synchronization between guests sharing the same memory object when
-interrupts are supported (this requires using the shared memory server).
+The server must be started on the host before any guest.
+It creates a shared memory object then waits for clients to connect on a unix
+socket.
-The server assigns each VM an ID number and sends this ID number to the QEMU
-process when the guest starts.
+For each client (QEMU process) that connects to the server:
+- the server assigns an ID for this client and sends this ID to him as the first
+ message,
+- the server sends a fd to the shared memory object to this client,
+- the server creates a new set of host eventfds associated to the new client and
+ sends this set to all already connected clients,
+- finally, the server sends all the eventfds sets for all clients to the new
+ client.
+
+The server signals all clients when one of them disconnects.
+
+The client IDs are limited to 16 bits because of the current implementation (see
+Doorbell register in 'PCI device registers' subsection). Hence only 65536
+clients are supported.
+
+All the file descriptors (fd to the shared memory, eventfds for each client)
+are passed to clients using SCM_RIGHTS over the server unix socket.
+
+Apart from the current ivshmem implementation in QEMU, an ivshmem client has
+been provided in qemu.git/contrib/ivshmem-client for debug.
+
+*QEMU as an ivshmem client*
+
+At initialisation, when creating the ivshmem device, QEMU gets its ID from the
+server then makes it available through BAR0 IVPosition register for the VM to
+use (see 'PCI device registers' subsection).
+QEMU then uses the fd to the shared memory to map it to BAR2.
+eventfds for all other clients received from the server are stored to implement
+BAR0 Doorbell register (see 'PCI device registers' subsection).
+Finally, eventfds assigned to this QEMU process are used to send interrupts in
+this VM.
+
+*PCI device registers*
+
+From the VM point of view, the ivshmem PCI device supports 4 registers of
+32-bits each.
enum ivshmem_registers {
IntrMask = 0,
@@ -49,8 +122,8 @@ bit to 0 and unmasked by setting the first bit to 1.
IVPosition Register: The IVPosition register is read-only and reports the
guest's ID number. The guest IDs are non-negative integers. When using the
server, since the server is a separate process, the VM ID will only be set when
-the device is ready (shared memory is received from the server and accessible via
-the device). If the device is not ready, the IVPosition will return -1.
+the device is ready (shared memory is received from the server and accessible
+via the device). If the device is not ready, the IVPosition will return -1.
Applications should ensure that they have a valid VM ID before accessing the
shared memory.
@@ -59,8 +132,8 @@ Doorbell register. The doorbell register is 32-bits, logically divided into
two 16-bit fields. The high 16-bits are the guest ID to interrupt and the low
16-bits are the interrupt vector to trigger. The semantics of the value
written to the doorbell depends on whether the device is using MSI or a regular
-pin-based interrupt. In short, MSI uses vectors while regular interrupts set the
-status register.
+pin-based interrupt. In short, MSI uses vectors while regular interrupts set
+the status register.
Regular Interrupts
@@ -71,7 +144,7 @@ interrupt in the destination guest.
Message Signalled Interrupts
-A ivshmem device may support multiple MSI vectors. If so, the lower 16-bits
+An ivshmem device may support multiple MSI vectors. If so, the lower 16-bits
written to the Doorbell register must be between 0 and the maximum number of
vectors the guest supports. The lower 16 bits written to the doorbell is the
MSI vector that will be raised in the destination guest. The number of MSI
@@ -83,14 +156,3 @@ interrupt itself should be communicated via the shared memory region. Devices
supporting multiple MSI vectors can use different vectors to indicate different
events have occurred. The semantics of interrupt vectors are left to the
user's discretion.
-
-
-Usage in the Guest
-------------------
-
-The shared memory device is intended to be used with the provided UIO driver.
-Very little configuration is needed. The guest should map BAR0 to access the
-registers (an array of 32-bit ints allows simple writing) and map BAR2 to
-access the shared memory region itself. The size of the shared memory region
-is specified when the guest (or shared memory server) is started. A guest may
-map the whole shared memory region or only part of it.
--
1.7.10.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU
2014-09-08 9:17 [Qemu-devel] [PATCH v6 0/3] ivshmem: update documentation, add client/server tools David Marchand
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server David Marchand
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 2/3] docs: update ivshmem device spec David Marchand
@ 2014-09-08 9:17 ` David Marchand
2014-09-08 9:49 ` Michael S. Tsirkin
2 siblings, 1 reply; 9+ messages in thread
From: David Marchand @ 2014-09-08 9:17 UTC (permalink / raw)
To: qemu-devel
Cc: kvm, mst, stefanha, claudio.fontana, armbru, arei.gonglei,
mkletzan, pbonzini, jani.kokkonen, cam
Send a protocol version as the first message from server, clients must close
communication if they don't support this protocol version.
Older QEMUs should be fine with this change in the protocol since they overrides
their own vm_id on reception of an id associated to no eventfd.
Signed-off-by: David Marchand <david.marchand@6wind.com>
---
contrib/ivshmem-client/ivshmem-client.c | 13 ++++++++++---
contrib/ivshmem-client/ivshmem-client.h | 1 +
contrib/ivshmem-server/ivshmem-server.c | 9 +++++++++
contrib/ivshmem-server/ivshmem-server.h | 1 +
docs/specs/ivshmem_device_spec.txt | 9 ++++++---
hw/misc/ivshmem.c | 27 +++++++++++++++++++++++++--
include/hw/misc/ivshmem.h | 17 +++++++++++++++++
7 files changed, 69 insertions(+), 8 deletions(-)
create mode 100644 include/hw/misc/ivshmem.h
diff --git a/contrib/ivshmem-client/ivshmem-client.c b/contrib/ivshmem-client/ivshmem-client.c
index 11c805c..4413e26 100644
--- a/contrib/ivshmem-client/ivshmem-client.c
+++ b/contrib/ivshmem-client/ivshmem-client.c
@@ -201,10 +201,17 @@ ivshmem_client_connect(IvshmemClient *client)
goto err_close;
}
- /* first, we expect our index + a fd == -1 */
+ /* first, we expect a protocol version */
+ if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
+ (tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) {
+ IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
+ goto err_close;
+ }
+
+ /* then, we expect our index + a fd == -1 */
if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 ||
client->local.id < 0 || fd != -1) {
- IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
+ IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
goto err_close;
}
IVSHMEM_CLIENT_DEBUG(client, "our_id=%ld\n", client->local.id);
@@ -216,7 +223,7 @@ ivshmem_client_connect(IvshmemClient *client)
if (fd >= 0) {
close(fd);
}
- IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
+ IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n");
goto err_close;
}
client->shm_fd = fd;
diff --git a/contrib/ivshmem-client/ivshmem-client.h b/contrib/ivshmem-client/ivshmem-client.h
index 284c4a3..9215f34 100644
--- a/contrib/ivshmem-client/ivshmem-client.h
+++ b/contrib/ivshmem-client/ivshmem-client.h
@@ -23,6 +23,7 @@
#include <sys/select.h>
#include "qemu/queue.h"
+#include "hw/misc/ivshmem.h"
/**
* Maximum number of notification vectors supported by the client
diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
index 91dc208..ea290f6 100644
--- a/contrib/ivshmem-server/ivshmem-server.c
+++ b/contrib/ivshmem-server/ivshmem-server.c
@@ -99,6 +99,15 @@ ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
{
int ret;
+ /* send our protocol version first */
+ ret = ivshmem_server_send_one_msg(peer->sock_fd, IVSHMEM_PROTOCOL_VERSION,
+ -1);
+ if (ret < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send version: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
/* send the peer id to the client */
ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
if (ret < 0) {
diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h
index f85dcd2..38df7bb 100644
--- a/contrib/ivshmem-server/ivshmem-server.h
+++ b/contrib/ivshmem-server/ivshmem-server.h
@@ -30,6 +30,7 @@
#include <sys/select.h>
#include "qemu/queue.h"
+#include "hw/misc/ivshmem.h"
/**
* Maximum number of notification vectors supported by the server
diff --git a/docs/specs/ivshmem_device_spec.txt b/docs/specs/ivshmem_device_spec.txt
index 12f338e..3435116 100644
--- a/docs/specs/ivshmem_device_spec.txt
+++ b/docs/specs/ivshmem_device_spec.txt
@@ -64,6 +64,8 @@ It creates a shared memory object then waits for clients to connect on a unix
socket.
For each client (QEMU process) that connects to the server:
+- the server sends a protocol version, if client does not support it, the client
+ closes the communication,
- the server assigns an ID for this client and sends this ID to him as the first
message,
- the server sends a fd to the shared memory object to this client,
@@ -86,9 +88,10 @@ been provided in qemu.git/contrib/ivshmem-client for debug.
*QEMU as an ivshmem client*
-At initialisation, when creating the ivshmem device, QEMU gets its ID from the
-server then makes it available through BAR0 IVPosition register for the VM to
-use (see 'PCI device registers' subsection).
+At initialisation, when creating the ivshmem device, QEMU first receives a
+protocol version and closes communication with server if it does not match.
+Then, QEMU gets its ID from the server then makes it available through BAR0
+IVPosition register for the VM to use (see 'PCI device registers' subsection).
QEMU then uses the fd to the shared memory to map it to BAR2.
eventfds for all other clients received from the server are stored to implement
BAR0 Doorbell register (see 'PCI device registers' subsection).
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index bd9d718..e08632b 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -26,6 +26,8 @@
#include "qemu/event_notifier.h"
#include "sysemu/char.h"
+#include "hw/misc/ivshmem.h"
+
#include <sys/mman.h>
#include <sys/types.h>
@@ -528,6 +530,27 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
}
}
+static void ivshmem_check_version(void *opaque, const uint8_t * buf, int flags)
+{
+ IVShmemState *s = opaque;
+ int tmp;
+ long version;
+
+ memcpy(&version, buf, sizeof(long));
+ tmp = qemu_chr_fe_get_msgfd(s->server_chr);
+ if (tmp != -1 || version != IVSHMEM_PROTOCOL_VERSION) {
+ fprintf(stderr, "incompatible version, you are connecting to a ivshmem-"
+ "server using a different protocol please check your setup\n");
+ qemu_chr_delete(s->server_chr);
+ s->server_chr = NULL;
+ return;
+ }
+
+ IVSHMEM_DPRINTF("version check ok, switch to real chardev handler\n");
+ qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive, ivshmem_read,
+ ivshmem_event, s);
+}
+
/* Select the MSI-X vectors used by device.
* ivshmem maps events to vectors statically, so
* we just enable all vectors on init and after reset. */
@@ -742,8 +765,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
s->eventfd_chr = g_malloc0(s->vectors * sizeof(CharDriverState *));
- qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive, ivshmem_read,
- ivshmem_event, s);
+ qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive,
+ ivshmem_check_version, ivshmem_event, s);
} else {
/* just map the file immediately, we're not using a server */
int fd;
diff --git a/include/hw/misc/ivshmem.h b/include/hw/misc/ivshmem.h
new file mode 100644
index 0000000..22c9f1f
--- /dev/null
+++ b/include/hw/misc/ivshmem.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+
+#ifndef _IVSHMEM_H_
+#define _IVSHMEM_H_
+
+/**
+ * Protocol version
+ */
+#define IVSHMEM_PROTOCOL_VERSION 0x0
+
+#endif
--
1.7.10.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU David Marchand
@ 2014-09-08 9:49 ` Michael S. Tsirkin
2014-09-23 15:58 ` Stefan Hajnoczi
0 siblings, 1 reply; 9+ messages in thread
From: Michael S. Tsirkin @ 2014-09-08 9:49 UTC (permalink / raw)
To: David Marchand
Cc: kvm, stefanha, claudio.fontana, qemu-devel, armbru, arei.gonglei,
mkletzan, pbonzini, jani.kokkonen, cam
On Mon, Sep 08, 2014 at 11:17:50AM +0200, David Marchand wrote:
> Send a protocol version as the first message from server, clients must close
> communication if they don't support this protocol version.
What's the motivation here?
This is at best a way to break all clients if an incompatible
change in the server is made.
Would not it be better to send a bitmap, or a list of supported
versions, so it's possible to write servers compatible
with multiple clients?
> Older QEMUs should be fine with this change in the protocol since they overrides
they override
> their own vm_id on reception of an id associated to no eventfd.
associated with?
I don't understand how compatibility works exactly,
a bit more explanation in code comments would be nice.
In particular new client won't work with old server,
will it?
>
> Signed-off-by: David Marchand <david.marchand@6wind.com>
> ---
> contrib/ivshmem-client/ivshmem-client.c | 13 ++++++++++---
> contrib/ivshmem-client/ivshmem-client.h | 1 +
> contrib/ivshmem-server/ivshmem-server.c | 9 +++++++++
> contrib/ivshmem-server/ivshmem-server.h | 1 +
> docs/specs/ivshmem_device_spec.txt | 9 ++++++---
> hw/misc/ivshmem.c | 27 +++++++++++++++++++++++++--
> include/hw/misc/ivshmem.h | 17 +++++++++++++++++
> 7 files changed, 69 insertions(+), 8 deletions(-)
> create mode 100644 include/hw/misc/ivshmem.h
>
> diff --git a/contrib/ivshmem-client/ivshmem-client.c b/contrib/ivshmem-client/ivshmem-client.c
> index 11c805c..4413e26 100644
> --- a/contrib/ivshmem-client/ivshmem-client.c
> +++ b/contrib/ivshmem-client/ivshmem-client.c
> @@ -201,10 +201,17 @@ ivshmem_client_connect(IvshmemClient *client)
> goto err_close;
> }
>
> - /* first, we expect our index + a fd == -1 */
> + /* first, we expect a protocol version */
> + if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
> + (tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) {
> + IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
> + goto err_close;
> + }
> +
> + /* then, we expect our index + a fd == -1 */
> if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 ||
> client->local.id < 0 || fd != -1) {
> - IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
> + IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
> goto err_close;
> }
> IVSHMEM_CLIENT_DEBUG(client, "our_id=%ld\n", client->local.id);
> @@ -216,7 +223,7 @@ ivshmem_client_connect(IvshmemClient *client)
> if (fd >= 0) {
> close(fd);
> }
> - IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
> + IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n");
> goto err_close;
> }
> client->shm_fd = fd;
> diff --git a/contrib/ivshmem-client/ivshmem-client.h b/contrib/ivshmem-client/ivshmem-client.h
> index 284c4a3..9215f34 100644
> --- a/contrib/ivshmem-client/ivshmem-client.h
> +++ b/contrib/ivshmem-client/ivshmem-client.h
> @@ -23,6 +23,7 @@
> #include <sys/select.h>
>
> #include "qemu/queue.h"
> +#include "hw/misc/ivshmem.h"
>
> /**
> * Maximum number of notification vectors supported by the client
> diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
> index 91dc208..ea290f6 100644
> --- a/contrib/ivshmem-server/ivshmem-server.c
> +++ b/contrib/ivshmem-server/ivshmem-server.c
> @@ -99,6 +99,15 @@ ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
> {
> int ret;
>
> + /* send our protocol version first */
> + ret = ivshmem_server_send_one_msg(peer->sock_fd, IVSHMEM_PROTOCOL_VERSION,
> + -1);
> + if (ret < 0) {
> + IVSHMEM_SERVER_DEBUG(server, "cannot send version: %s\n",
> + strerror(errno));
> + return -1;
> + }
> +
> /* send the peer id to the client */
> ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
> if (ret < 0) {
> diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h
> index f85dcd2..38df7bb 100644
> --- a/contrib/ivshmem-server/ivshmem-server.h
> +++ b/contrib/ivshmem-server/ivshmem-server.h
> @@ -30,6 +30,7 @@
> #include <sys/select.h>
>
> #include "qemu/queue.h"
> +#include "hw/misc/ivshmem.h"
>
> /**
> * Maximum number of notification vectors supported by the server
> diff --git a/docs/specs/ivshmem_device_spec.txt b/docs/specs/ivshmem_device_spec.txt
> index 12f338e..3435116 100644
> --- a/docs/specs/ivshmem_device_spec.txt
> +++ b/docs/specs/ivshmem_device_spec.txt
> @@ -64,6 +64,8 @@ It creates a shared memory object then waits for clients to connect on a unix
> socket.
>
> For each client (QEMU process) that connects to the server:
> +- the server sends a protocol version, if client does not support it, the client
> + closes the communication,
> - the server assigns an ID for this client and sends this ID to him as the first
> message,
> - the server sends a fd to the shared memory object to this client,
> @@ -86,9 +88,10 @@ been provided in qemu.git/contrib/ivshmem-client for debug.
>
> *QEMU as an ivshmem client*
>
> -At initialisation, when creating the ivshmem device, QEMU gets its ID from the
> -server then makes it available through BAR0 IVPosition register for the VM to
> -use (see 'PCI device registers' subsection).
> +At initialisation, when creating the ivshmem device, QEMU first receives a
> +protocol version and closes communication with server if it does not match.
> +Then, QEMU gets its ID from the server then makes it available through BAR0
> +IVPosition register for the VM to use (see 'PCI device registers' subsection).
> QEMU then uses the fd to the shared memory to map it to BAR2.
> eventfds for all other clients received from the server are stored to implement
> BAR0 Doorbell register (see 'PCI device registers' subsection).
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index bd9d718..e08632b 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -26,6 +26,8 @@
> #include "qemu/event_notifier.h"
> #include "sysemu/char.h"
>
> +#include "hw/misc/ivshmem.h"
> +
> #include <sys/mman.h>
> #include <sys/types.h>
>
> @@ -528,6 +530,27 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
> }
> }
>
> +static void ivshmem_check_version(void *opaque, const uint8_t * buf, int flags)
> +{
> + IVShmemState *s = opaque;
> + int tmp;
> + long version;
> +
> + memcpy(&version, buf, sizeof(long));
> + tmp = qemu_chr_fe_get_msgfd(s->server_chr);
> + if (tmp != -1 || version != IVSHMEM_PROTOCOL_VERSION) {
> + fprintf(stderr, "incompatible version, you are connecting to a ivshmem-"
> + "server using a different protocol please check your setup\n");
> + qemu_chr_delete(s->server_chr);
> + s->server_chr = NULL;
> + return;
> + }
> +
> + IVSHMEM_DPRINTF("version check ok, switch to real chardev handler\n");
> + qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive, ivshmem_read,
> + ivshmem_event, s);
> +}
> +
> /* Select the MSI-X vectors used by device.
> * ivshmem maps events to vectors statically, so
> * we just enable all vectors on init and after reset. */
> @@ -742,8 +765,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
>
> s->eventfd_chr = g_malloc0(s->vectors * sizeof(CharDriverState *));
>
> - qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive, ivshmem_read,
> - ivshmem_event, s);
> + qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive,
> + ivshmem_check_version, ivshmem_event, s);
> } else {
> /* just map the file immediately, we're not using a server */
> int fd;
> diff --git a/include/hw/misc/ivshmem.h b/include/hw/misc/ivshmem.h
> new file mode 100644
> index 0000000..22c9f1f
> --- /dev/null
> +++ b/include/hw/misc/ivshmem.h
> @@ -0,0 +1,17 @@
> +/*
> + * Copyright 6WIND S.A., 2014
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * (at your option) any later version. See the COPYING file in the
> + * top-level directory.
> + */
> +
> +#ifndef _IVSHMEM_H_
> +#define _IVSHMEM_H_
> +
> +/**
> + * Protocol version
> + */
> +#define IVSHMEM_PROTOCOL_VERSION 0x0
> +
> +#endif
> --
> 1.7.10.4
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server David Marchand
@ 2014-09-08 9:51 ` Michael S. Tsirkin
0 siblings, 0 replies; 9+ messages in thread
From: Michael S. Tsirkin @ 2014-09-08 9:51 UTC (permalink / raw)
To: David Marchand
Cc: Olivier Matz, kvm, stefanha, claudio.fontana, qemu-devel, armbru,
arei.gonglei, mkletzan, pbonzini, jani.kokkonen, cam
On Mon, Sep 08, 2014 at 11:17:48AM +0200, David Marchand wrote:
...
> diff --git a/configure b/configure
> index 961bf6f..a41a16c 100755
> --- a/configure
> +++ b/configure
> @@ -4125,6 +4125,9 @@ if test "$want_tools" = "yes" ; then
> if [ "$linux" = "yes" -o "$bsd" = "yes" -o "$solaris" = "yes" ] ; then
> tools="qemu-nbd\$(EXESUF) $tools"
> fi
> + if [ "$kvm" = "yes" ] ; then
> + tools="ivshmem-client\$(EXESUF) ivshmem-server\$(EXESUF) $tools"
> + fi
Why are you tying this to kvm btw?
Shouldn't be for any linux host?
> fi
> if test "$softmmu" = yes ; then
> if test "$virtfs" != no ; then
...
> diff --git a/contrib/ivshmem-client/ivshmem-client.h b/contrib/ivshmem-client/ivshmem-client.h
> new file mode 100644
> index 0000000..284c4a3
> --- /dev/null
> +++ b/contrib/ivshmem-client/ivshmem-client.h
> @@ -0,0 +1,212 @@
> +/*
> + * Copyright 6WIND S.A., 2014
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * (at your option) any later version. See the COPYING file in the
> + * top-level directory.
> + */
> +
> +#ifndef _IVSHMEM_CLIENT_H_
> +#define _IVSHMEM_CLIENT_H_
> +
> +/**
> + * This file provides helper to implement an ivshmem client. It is used
> + * on the host to ask QEMU to send an interrupt to an ivshmem PCI device in a
> + * guest. QEMU also implements an ivshmem client similar to this one, they both
> + * connect to an ivshmem server.
> + *
> + * A standalone ivshmem client based on this file is provided for debug/test
> + * purposes.
> + */
> +
> +#include <limits.h>
> +#include <sys/select.h>
> +
> +#include "qemu/queue.h"
> +
> +/**
> + * Maximum number of notification vectors supported by the client
> + */
> +#define IVSHMEM_CLIENT_MAX_VECTORS 64
> +
> +/**
> + * Structure storing a peer
> + *
> + * Each time a client connects to an ivshmem server, it is advertised to
> + * all connected clients through the unix socket. When our ivshmem
> + * client receives a notification, it creates a IvshmemClientPeer
> + * structure to store the infos of this peer.
> + *
> + * This structure is also used to store the information of our own
> + * client in (IvshmemClient)->local.
> + */
> +typedef struct IvshmemClientPeer {
> + QTAILQ_ENTRY(IvshmemClientPeer) next; /**< next in list*/
Needs space before */
> + long id; /**< the id of the peer */
> + int vectors[IVSHMEM_CLIENT_MAX_VECTORS]; /**< one fd per vector */
> + unsigned vectors_count; /**< number of vectors */
I would do just /* text */ here, otherewise people might think
they have to copy this comment style.
> +} IvshmemClientPeer;
an empty line wouldn't hurt here.
> +QTAILQ_HEAD(IvshmemClientPeerList, IvshmemClientPeer);
> +
> +typedef struct IvshmemClientPeerList IvshmemClientPeerList;
> +typedef struct IvshmemClient IvshmemClient;
> +
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v6 2/3] docs: update ivshmem device spec
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 2/3] docs: update ivshmem device spec David Marchand
@ 2014-09-08 10:01 ` Michael S. Tsirkin
0 siblings, 0 replies; 9+ messages in thread
From: Michael S. Tsirkin @ 2014-09-08 10:01 UTC (permalink / raw)
To: David Marchand
Cc: kvm, stefanha, claudio.fontana, qemu-devel, armbru, arei.gonglei,
mkletzan, pbonzini, jani.kokkonen, cam
On Mon, Sep 08, 2014 at 11:17:49AM +0200, David Marchand wrote:
> Add some notes on the parts needed to use ivshmem devices: more specifically,
> explain the purpose of an ivshmem server and the basic concept to use the
> ivshmem devices in guests.
> Move some parts of the documentation and re-organise it.
>
> Signed-off-by: David Marchand <david.marchand@6wind.com>
> Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> docs/specs/ivshmem_device_spec.txt | 124 +++++++++++++++++++++++++++---------
> 1 file changed, 93 insertions(+), 31 deletions(-)
>
> diff --git a/docs/specs/ivshmem_device_spec.txt b/docs/specs/ivshmem_device_spec.txt
> index 667a862..12f338e 100644
> --- a/docs/specs/ivshmem_device_spec.txt
> +++ b/docs/specs/ivshmem_device_spec.txt
> @@ -2,30 +2,103 @@
> Device Specification for Inter-VM shared memory device
> ------------------------------------------------------
>
> -The Inter-VM shared memory device is designed to share a region of memory to
> -userspace in multiple virtual guests. The memory region does not belong to any
> -guest, but is a POSIX memory object on the host. Optionally, the device may
> -support sending interrupts to other guests sharing the same memory region.
> +The Inter-VM shared memory device is designed to share a memory region (created
> +on the host via the POSIX shared memory API) between multiple QEMU processes
> +running different guests. In order for all guests to be able to pick up the
> +shared memory area, it is modeled by QEMU as a PCI device exposing said memory
> +to the guest as a PCI BAR.
> +The memory region does not belong to any guest, but is a POSIX memory object on
> +the host. The host can access this shared memory if needed.
> +
> +The device also provides an optional communication mechanism between guests
> +sharing the same memory object. More details about that in the section 'Guest to
> +guest communication' section.
>
>
> The Inter-VM PCI device
> -----------------------
>
> -*BARs*
> +From the VM point of view, the ivshmem PCI device supports three BARs.
> +
> +- BAR0 is a 1 Kbyte MMIO region to support registers and interrupts when MSI is
> + not used.
> +- BAR1 is used for MSI-X when it is enabled in the device.
> +- BAR2 is used to access the shared memory object.
> +
BAR2 or resource 2?
Not the same if BAR1 is 64 bit.
Guests are using this already, right?
We can't change it?
Unfortunate since switching shared memory to BAR1
would have avoided the ambiguity.
Oh well, we don't want to break guests for such a minor gain.
And what happens if there's no MSI-X capability?
BAR1 unused?
> +It is your choice how to use the device but you must choose between two
> +behaviors :
Make this a separate chapter, this is not from VM POV anymore.
> +
> +- basically, if you only need the shared memory part, you will map BAR2.
> + This way, you have access to the shared memory in guest and can use it as you
> + see fit (memnic, for example, uses it in userland
> + http://dpdk.org/browse/memnic).
> +
> +- BAR0 and BAR1 are used to implement an optional communication mechanism
> + through interrupts in the guests. If you need an event mechanism between the
> + guests accessing the shared memory, you will most likely want to write a
> + kernel driver that will handle interrupts. See details in the section 'Guest
> + to guest communication' section.
> +
> +The behavior is chosen when starting your QEMU processes:
> +- no communication mechanism needed, the first QEMU to start creates the shared
> + memory on the host, subsequent QEMU processes will use it.
> +
> +- communication mechanism needed, an ivshmem server must be started before any
> + QEMU processes, then each QEMU process connects to the server unix socket.
> +
> +For more details on the QEMU ivshmem parameters, see qemu-doc documentation.
> +
> +
I know you did not start it but don't add more cases of two
empty lines please.
> +Guest to guest communication
> +----------------------------
> +
> +This section details the communication mechanism between the guests accessing
> +the ivhsmem shared memory.
In in fact, below text is QEMU to QEMU protocol.
There are 3 types of communication:
qemu to vm: e.g. pci registers
qemu to another ivshmem server/client: e.g. domain sockets
vm to vm: using shared memory, interrupts (can be mediated by qemu)
Pls don't mix these up, seperate them in the documentation.
>
> -The device supports three BARs. BAR0 is a 1 Kbyte MMIO region to support
> -registers. BAR1 is used for MSI-X when it is enabled in the device. BAR2 is
> -used to map the shared memory object from the host. The size of BAR2 is
> -specified when the guest is started and must be a power of 2 in size.
> +*ivshmem server*
>
> -*Registers*
> +This server code is available in qemu.git/contrib/ivshmem-server.
>
> -The device currently supports 4 registers of 32-bits each. Registers
> -are used for synchronization between guests sharing the same memory object when
> -interrupts are supported (this requires using the shared memory server).
> +The server must be started on the host before any guest.
> +It creates a shared memory object then waits for clients to connect on a unix
> +socket.
>
> -The server assigns each VM an ID number and sends this ID number to the QEMU
> -process when the guest starts.
> +For each client (QEMU process) that connects to the server:
> +- the server assigns an ID for this client and sends this ID to him as the first
> + message,
> +- the server sends a fd to the shared memory object to this client,
> +- the server creates a new set of host eventfds associated to the new client and
> + sends this set to all already connected clients,
> +- finally, the server sends all the eventfds sets for all clients to the new
> + client.
> +
> +The server signals all clients when one of them disconnects.
> +
> +The client IDs are limited to 16 bits because of the current implementation (see
> +Doorbell register in 'PCI device registers' subsection). Hence only 65536
> +clients are supported.
> +
> +All the file descriptors (fd to the shared memory, eventfds for each client)
> +are passed to clients using SCM_RIGHTS over the server unix socket.
> +
> +Apart from the current ivshmem implementation in QEMU, an ivshmem client has
> +been provided in qemu.git/contrib/ivshmem-client for debug.
> +
> +*QEMU as an ivshmem client*
> +
> +At initialisation, when creating the ivshmem device, QEMU gets its ID from the
> +server then makes it available through BAR0 IVPosition register for the VM to
> +use (see 'PCI device registers' subsection).
> +QEMU then uses the fd to the shared memory to map it to BAR2.
> +eventfds for all other clients received from the server are stored to implement
> +BAR0 Doorbell register (see 'PCI device registers' subsection).
> +Finally, eventfds assigned to this QEMU process are used to send interrupts in
> +this VM.
> +
> +*PCI device registers*
> +
> +From the VM point of view, the ivshmem PCI device supports 4 registers of
> +32-bits each.
>
> enum ivshmem_registers {
> IntrMask = 0,
> @@ -49,8 +122,8 @@ bit to 0 and unmasked by setting the first bit to 1.
> IVPosition Register: The IVPosition register is read-only and reports the
> guest's ID number. The guest IDs are non-negative integers. When using the
> server, since the server is a separate process, the VM ID will only be set when
> -the device is ready (shared memory is received from the server and accessible via
> -the device). If the device is not ready, the IVPosition will return -1.
> +the device is ready (shared memory is received from the server and accessible
> +via the device). If the device is not ready, the IVPosition will return -1.
> Applications should ensure that they have a valid VM ID before accessing the
> shared memory.
>
> @@ -59,8 +132,8 @@ Doorbell register. The doorbell register is 32-bits, logically divided into
> two 16-bit fields. The high 16-bits are the guest ID to interrupt and the low
> 16-bits are the interrupt vector to trigger. The semantics of the value
> written to the doorbell depends on whether the device is using MSI or a regular
> -pin-based interrupt. In short, MSI uses vectors while regular interrupts set the
> -status register.
> +pin-based interrupt. In short, MSI uses vectors while regular interrupts set
> +the status register.
>
> Regular Interrupts
>
> @@ -71,7 +144,7 @@ interrupt in the destination guest.
>
> Message Signalled Interrupts
>
> -A ivshmem device may support multiple MSI vectors. If so, the lower 16-bits
> +An ivshmem device may support multiple MSI vectors. If so, the lower 16-bits
> written to the Doorbell register must be between 0 and the maximum number of
> vectors the guest supports. The lower 16 bits written to the doorbell is the
> MSI vector that will be raised in the destination guest. The number of MSI
> @@ -83,14 +156,3 @@ interrupt itself should be communicated via the shared memory region. Devices
> supporting multiple MSI vectors can use different vectors to indicate different
> events have occurred. The semantics of interrupt vectors are left to the
> user's discretion.
> -
> -
> -Usage in the Guest
> -------------------
> -
> -The shared memory device is intended to be used with the provided UIO driver.
> -Very little configuration is needed. The guest should map BAR0 to access the
> -registers (an array of 32-bit ints allows simple writing) and map BAR2 to
> -access the shared memory region itself. The size of the shared memory region
> -is specified when the guest (or shared memory server) is started. A guest may
> -map the whole shared memory region or only part of it.
> --
> 1.7.10.4
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU
2014-09-08 9:49 ` Michael S. Tsirkin
@ 2014-09-23 15:58 ` Stefan Hajnoczi
2014-09-25 8:38 ` David Marchand
0 siblings, 1 reply; 9+ messages in thread
From: Stefan Hajnoczi @ 2014-09-23 15:58 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: kvm, armbru, claudio.fontana, David Marchand, qemu-devel,
arei.gonglei, mkletzan, pbonzini, jani.kokkonen, cam
[-- Attachment #1: Type: text/plain, Size: 1353 bytes --]
On Mon, Sep 08, 2014 at 12:49:48PM +0300, Michael S. Tsirkin wrote:
> On Mon, Sep 08, 2014 at 11:17:50AM +0200, David Marchand wrote:
> > Send a protocol version as the first message from server, clients must close
> > communication if they don't support this protocol version.
>
> What's the motivation here?
> This is at best a way to break all clients if an incompatible
> change in the server is made.
> Would not it be better to send a bitmap, or a list of supported
> versions, so it's possible to write servers compatible
> with multiple clients?
I'm not sure a full-fledged feature negotiation system is needed. The
ivshmem protocol is local to the host and all participants are under
control of the administrator.
I suggested a protocol version to protect against misconfiguration. For
example, building QEMU from source but talking to an outdated ivhsmem
server that is still running from before.
Remember that ivshmem-server and QEMU are shipped together by the
distro. So in 99% of the cases they will have the same version anyway.
But we want to protect against rare misconfiguration that break things
(user mixing and matching incompatible software).
The only reason I can see for fancy negotiation is to make life easier
for proprietary third-party software, which I don't care about or like.
Stefan
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU
2014-09-23 15:58 ` Stefan Hajnoczi
@ 2014-09-25 8:38 ` David Marchand
0 siblings, 0 replies; 9+ messages in thread
From: David Marchand @ 2014-09-25 8:38 UTC (permalink / raw)
To: Stefan Hajnoczi, Michael S. Tsirkin
Cc: kvm, claudio.fontana, qemu-devel, armbru, arei.gonglei, mkletzan,
pbonzini, jani.kokkonen, cam
On 09/23/2014 05:58 PM, Stefan Hajnoczi wrote:
> I'm not sure a full-fledged feature negotiation system is needed. The
> ivshmem protocol is local to the host and all participants are under
> control of the administrator.
>
> I suggested a protocol version to protect against misconfiguration. For
> example, building QEMU from source but talking to an outdated ivhsmem
> server that is still running from before.
>
> Remember that ivshmem-server and QEMU are shipped together by the
> distro. So in 99% of the cases they will have the same version anyway.
> But we want to protect against rare misconfiguration that break things
> (user mixing and matching incompatible software).
Ok, so how about keeping with this simple mechanism at the moment ?
If this versionning system is too limited in the future, I think we will
need a global rework on the protocol, anyway.
--
David Marchand
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2014-09-25 8:47 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-09-08 9:17 [Qemu-devel] [PATCH v6 0/3] ivshmem: update documentation, add client/server tools David Marchand
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 1/3] contrib: add ivshmem client and server David Marchand
2014-09-08 9:51 ` Michael S. Tsirkin
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 2/3] docs: update ivshmem device spec David Marchand
2014-09-08 10:01 ` Michael S. Tsirkin
2014-09-08 9:17 ` [Qemu-devel] [PATCH v6 3/3] ivshmem: add check on protocol version in QEMU David Marchand
2014-09-08 9:49 ` Michael S. Tsirkin
2014-09-23 15:58 ` Stefan Hajnoczi
2014-09-25 8:38 ` David Marchand
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