this code is a standalone server which will pass file descriptors for the shared
memory region and eventfds to support interrupts between guests using inter-VM
shared memory.
---
contrib/ivshmem-server/Makefile | 16 ++
contrib/ivshmem-server/README | 30 +++
contrib/ivshmem-server/ivshmem_server.c | 339 +++++++++++++++++++++++++++++++
contrib/ivshmem-server/send_scm.c | 208 +++++++++++++++++++
contrib/ivshmem-server/send_scm.h | 19 ++
5 files changed, 612 insertions(+), 0 deletions(-)
create mode 100644 contrib/ivshmem-server/Makefile
create mode 100644 contrib/ivshmem-server/README
create mode 100644 contrib/ivshmem-server/ivshmem_server.c
create mode 100644 contrib/ivshmem-server/send_scm.c
create mode 100644 contrib/ivshmem-server/send_scm.h
diff --git a/contrib/ivshmem-server/Makefile b/contrib/ivshmem-server/Makefile
new file mode 100644
index 0000000..da40ffa
--- /dev/null
+++ b/contrib/ivshmem-server/Makefile
@@ -0,0 +1,16 @@
+CC = gcc
+CFLAGS = -O3 -Wall -Werror
+LIBS = -lrt
+
+# a very simple makefile to build the inter-VM shared memory server
+
+all: ivshmem_server
+
+.c.o:
+ $(CC) $(CFLAGS) -c $^ -o $@
+
+ivshmem_server: ivshmem_server.o send_scm.o
+ $(CC) $(CFLAGS) -o $@ $^ $(LIBS)
+
+clean:
+ rm -f *.o ivshmem_server
diff --git a/contrib/ivshmem-server/README b/contrib/ivshmem-server/README
new file mode 100644
index 0000000..b1fc2a2
--- /dev/null
+++ b/contrib/ivshmem-server/README
@@ -0,0 +1,30 @@
+Using the ivshmem shared memory server
+--------------------------------------
+
+This server is only supported on Linux.
+
+To use the shared memory server, first compile it. Running 'make' should
+accomplish this. An executable named 'ivshmem_server' will be built.
+
+to display the options run:
+
+./ivshmem_server -h
+
+Options
+-------
+
+ -h print help message
+
+ -p <path on host>
+ unix socket to listen on. The qemu-kvm chardev needs to connect on
+ this socket. (default: '/tmp/ivshmem_socket')
+
+ -s <string>
+ POSIX shared object to create that is the shared memory (default: 'ivshmem')
+
+ -m <#>
+ size of the POSIX object in MBs (default: 1)
+
+ -n <#>
+ number of eventfds for each guest. This number must match the
+ 'vectors' argument passed the ivshmem device. (default: 1)
diff --git a/contrib/ivshmem-server/ivshmem_server.c b/contrib/ivshmem-server/ivshmem_server.c
new file mode 100644
index 0000000..2dbf76f
--- /dev/null
+++ b/contrib/ivshmem-server/ivshmem_server.c
@@ -0,0 +1,339 @@
+/*
+ * A stand-alone shared memory server for inter-VM shared memory for KVM
+*/
+
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/eventfd.h>
+#include <sys/mman.h>
+#include <sys/select.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "send_scm.h"
+
+#define DEFAULT_SOCK_PATH "/tmp/ivshmem_socket"
+#define DEFAULT_SHM_OBJ "ivshmem"
+
+#define DEBUG 1
+
+typedef struct server_state {
+ vmguest_t *live_vms;
+ int nr_allocated_vms;
+ int shm_size;
+ long live_count;
+ long total_count;
+ int shm_fd;
+ char * path;
+ char * shmobj;
+ int maxfd, conn_socket;
+ long msi_vectors;
+} server_state_t;
+
+void usage(char const *prg);
+int find_set(fd_set * readset, int max);
+void print_vec(server_state_t * s, const char * c);
+
+void add_new_guest(server_state_t * s);
+void parse_args(int argc, char **argv, server_state_t * s);
+int create_listening_socket(char * path);
+
+int main(int argc, char ** argv)
+{
+ fd_set readset;
+ server_state_t * s;
+
+ s = (server_state_t *)calloc(1, sizeof(server_state_t));
+
+ s->live_count = 0;
+ s->total_count = 0;
+ parse_args(argc, argv, s);
+
+ /* open shared memory file */
+ if ((s->shm_fd = shm_open(s->shmobj, O_CREAT|O_RDWR, S_IRWXU)) < 0)
+ {
+ fprintf(stderr, "kvm_ivshmem: could not open shared file\n");
+ exit(-1);
+ }
+
+ ftruncate(s->shm_fd, s->shm_size);
+
+ s->conn_socket = create_listening_socket(s->path);
+
+ s->maxfd = s->conn_socket;
+
+ for(;;) {
+ int ret, handle, i;
+ char buf[1024];
+
+ print_vec(s, "vm_sockets");
+
+ FD_ZERO(&readset);
+ /* conn socket is in Live_vms at posn 0 */
+ FD_SET(s->conn_socket, &readset);
+ for (i = 0; i < s->total_count; i++) {
+ if (s->live_vms[i].alive != 0) {
+ FD_SET(s->live_vms[i].sockfd, &readset);
+ }
+ }
+
+ printf("\nWaiting (maxfd = %d)\n", s->maxfd);
+
+ ret = select(s->maxfd + 1, &readset, NULL, NULL, NULL);
+
+ if (ret == -1) {
+ perror("select()");
+ }
+
+ handle = find_set(&readset, s->maxfd + 1);
+ if (handle == -1) continue;
+
+ if (handle == s->conn_socket) {
+
+ printf("[NC] new connection\n");
+ FD_CLR(s->conn_socket, &readset);
+
+ /* The Total_count is equal to the new guests VM ID */
+ add_new_guest(s);
+
+ /* update our the maximum file descriptor number */
+ s->maxfd = s->live_vms[s->total_count - 1].sockfd > s->maxfd ?
+ s->live_vms[s->total_count - 1].sockfd : s->maxfd;
+
+ s->live_count++;
+ printf("Live_count is %ld\n", s->live_count);
+
+ } else {
+ /* then we have received a disconnection */
+ int recv_ret;
+ long i, j;
+ long deadposn = -1;
+
+ recv_ret = recv(handle, buf, 1, 0);
+
+ printf("[DC] recv returned %d\n", recv_ret);
+
+ /* find the dead VM in our list and move it do the dead list. */
+ for (i = 0; i < s->total_count; i++) {
+ if (s->live_vms[i].sockfd == handle) {
+ deadposn = i;
+ s->live_vms[i].alive = 0;
+ close(s->live_vms[i].sockfd);
+
+ for (j = 0; j < s->msi_vectors; j++) {
+ close(s->live_vms[i].efd[j]);
+ }
+
+ free(s->live_vms[i].efd);
+ s->live_vms[i].sockfd = -1;
+ break;
+ }
+ }
+
+ for (j = 0; j < s->total_count; j++) {
+ /* update remaining clients that one client has left/died */
+ if (s->live_vms[j].alive) {
+ printf("[UD] sending kill of fd[%ld] to %ld\n",
+ deadposn, j);
+ sendKill(s->live_vms[j].sockfd, deadposn, sizeof(deadposn));
+ }
+ }
+
+ s->live_count--;
+
+ /* close the socket for the departed VM */
+ close(handle);
+ }
+
+ }
+
+ return 0;
+}
+
+void add_new_guest(server_state_t * s) {
+
+ struct sockaddr_un remote;
+ socklen_t t = sizeof(remote);
+ long i, j;
+ int vm_sock;
+ long new_posn;
+ long neg1 = -1;
+
+ vm_sock = accept(s->conn_socket, (struct sockaddr *)&remote, &t);
+
+ if ( vm_sock == -1 ) {
+ perror("accept");
+ exit(1);
+ }
+
+ new_posn = s->total_count;
+
+ if (new_posn == s->nr_allocated_vms) {
+ printf("increasing vm slots\n");
+ s->nr_allocated_vms = s->nr_allocated_vms * 2;
+ if (s->nr_allocated_vms < 16)
+ s->nr_allocated_vms = 16;
+ s->live_vms = realloc(s->live_vms,
+ s->nr_allocated_vms * sizeof(vmguest_t));
+
+ if (s->live_vms == NULL) {
+ fprintf(stderr, "realloc failed - quitting\n");
+ exit(-1);
+ }
+ }
+
+ s->live_vms[new_posn].posn = new_posn;
+ printf("[NC] Live_vms[%ld]\n", new_posn);
+ s->live_vms[new_posn].efd = (int *) malloc(sizeof(int));
+ for (i = 0; i < s->msi_vectors; i++) {
+ s->live_vms[new_posn].efd[i] = eventfd(0, 0);
+ printf("\tefd[%ld] = %d\n", i, s->live_vms[new_posn].efd[i]);
+ }
+ s->live_vms[new_posn].sockfd = vm_sock;
+ s->live_vms[new_posn].alive = 1;
+
+
+ sendPosition(vm_sock, new_posn);
+ sendUpdate(vm_sock, neg1, sizeof(long), s->shm_fd);
+ printf("[NC] trying to send fds to new connection\n");
+ sendRights(vm_sock, new_posn, sizeof(new_posn), s->live_vms, s->msi_vectors);
+
+ printf("[NC] Connected (count = %ld).\n", new_posn);
+ for (i = 0; i < new_posn; i++) {
+ if (s->live_vms[i].alive) {
+ // ping all clients that a new client has joined
+ printf("[UD] sending fd[%ld] to %ld\n", new_posn, i);
+ for (j = 0; j < s->msi_vectors; j++) {
+ printf("\tefd[%ld] = [%d]", j, s->live_vms[new_posn].efd[j]);
+ sendUpdate(s->live_vms[i].sockfd, new_posn,
+ sizeof(new_posn), s->live_vms[new_posn].efd[j]);
+ }
+ printf("\n");
+ }
+ }
+
+ s->total_count++;
+}
+
+int create_listening_socket(char * path) {
+
+ struct sockaddr_un local;
+ int len, conn_socket;
+
+ if ((conn_socket = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
+ perror("socket");
+ exit(1);
+ }
+
+ local.sun_family = AF_UNIX;
+ strcpy(local.sun_path, path);
+ unlink(local.sun_path);
+ len = strlen(local.sun_path) + sizeof(local.sun_family);
+ if (bind(conn_socket, (struct sockaddr *)&local, len) == -1) {
+ perror("bind");
+ exit(1);
+ }
+
+ if (listen(conn_socket, 5) == -1) {
+ perror("listen");
+ exit(1);
+ }
+
+ return conn_socket;
+
+}
+
+void parse_args(int argc, char **argv, server_state_t * s) {
+
+ int c;
+
+ s->shm_size = 1024 * 1024; // default shm_size
+ s->path = NULL;
+ s->shmobj = NULL;
+ s->msi_vectors = 1;
+
+ while ((c = getopt(argc, argv, "hp:s:m:n:")) != -1) {
+
+ switch (c) {
+ // path to listening socket
+ case 'p':
+ s->path = optarg;
+ break;
+ // name of shared memory object
+ case 's':
+ s->shmobj = optarg;
+ break;
+ // size of shared memory object
+ case 'm':
+ s->shm_size = atol(optarg)*1024*1024;
+ break;
+ case 'n':
+ s->msi_vectors = atol(optarg);
+ break;
+ case 'h':
+ default:
+ usage(argv[0]);
+ exit(1);
+ }
+ }
+
+ if (s->path == NULL) {
+ s->path = strdup(DEFAULT_SOCK_PATH);
+ }
+
+ printf("listening socket: %s\n", s->path);
+
+ if (s->shmobj == NULL) {
+ s->shmobj = strdup(DEFAULT_SHM_OBJ);
+ }
+
+ printf("shared object: %s\n", s->shmobj);
+ printf("shared object size: %d MB\n", s->shm_size);
+
+}
+
+void print_vec(server_state_t * s, const char * c) {
+
+ int i, j;
+
+#if DEBUG
+ printf("%s (%ld) = ", c, s->total_count);
+ for (i = 0; i < s->total_count; i++) {
+ if (s->live_vms[i].alive) {
+ for (j = 0; j < s->msi_vectors; j++) {
+ printf("[%d|%d] ", s->live_vms[i].sockfd, s->live_vms[i].efd[j]);
+ }
+ }
+ }
+ printf("\n");
+#endif
+
+}
+
+int find_set(fd_set * readset, int max) {
+
+ int i;
+
+ for (i = 1; i < max; i++) {
+ if (FD_ISSET(i, readset)) {
+ return i;
+ }
+ }
+
+ printf("nothing set\n");
+ return -1;
+
+}
+
+void usage(char const *prg) {
+ fprintf(stderr, "use: %s [-h] [-p <unix socket>] [-s <shm obj>]
+ [-m <size in MB>] [-n <# of MSI vectors>]\n", prg);
+}
+
+
diff --git a/contrib/ivshmem-server/send_scm.c b/contrib/ivshmem-server/send_scm.c
new file mode 100644
index 0000000..b1bb4a3
--- /dev/null
+++ b/contrib/ivshmem-server/send_scm.c
@@ -0,0 +1,208 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <sys/un.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <poll.h>
+#include "send_scm.h"
+
+#ifndef POLLRDHUP
+#define POLLRDHUP 0x2000
+#endif
+
+int readUpdate(int fd, long * posn, int * newfd)
+{
+ struct msghdr msg;
+ struct iovec iov[1];
+ struct cmsghdr *cmptr;
+ size_t len;
+ size_t msg_size = sizeof(int);
+ char control[CMSG_SPACE(msg_size)];
+
+ msg.msg_name = 0;
+ msg.msg_namelen = 0;
+ msg.msg_control = control;
+ msg.msg_controllen = sizeof(control);
+ msg.msg_flags = 0;
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ iov[0].iov_base = &posn;
+ iov[0].iov_len = sizeof(posn);
+
+ do {
+ len = recvmsg(fd, &msg, 0);
+ } while (len == (size_t) (-1) && (errno == EINTR || errno == EAGAIN));
+
+ printf("iov[0].buf is %ld\n", *((long *)iov[0].iov_base));
+ printf("len is %ld\n", len);
+ // TODO: Logging
+ if (len == (size_t) (-1)) {
+ perror("recvmsg()");
+ return -1;
+ }
+
+ if (msg.msg_controllen < sizeof(struct cmsghdr))
+ return *posn;
+
+ for (cmptr = CMSG_FIRSTHDR(&msg); cmptr != NULL;
+ cmptr = CMSG_NXTHDR(&msg, cmptr)) {
+ if (cmptr->cmsg_level != SOL_SOCKET ||
+ cmptr->cmsg_type != SCM_RIGHTS){
+ printf("continuing %ld\n", sizeof(size_t));
+ printf("read msg_size = %ld\n", msg_size);
+ if (cmptr->cmsg_len != sizeof(control))
+ printf("not equal (%ld != %ld)\n",cmptr->cmsg_len,sizeof(control));
+ continue;
+ }
+
+ memcpy(newfd, CMSG_DATA(cmptr), sizeof(int));
+ printf("posn is %ld (fd = %d)\n", *posn, *newfd);
+ return 0;
+ }
+
+ fprintf(stderr, "bad data in packet\n");
+ return -1;
+}
+
+int readRights(int fd, long count, size_t count_len, int **fds, int msi_vectors)
+{
+ int j, newfd;
+
+ for (; ;){
+ long posn = 0;
+
+ readUpdate(fd, &posn, &newfd);
+ printf("reading posn %ld ", posn);
+ fds[posn] = (int *)malloc (msi_vectors * sizeof(int));
+ fds[posn][0] = newfd;
+ for (j = 1; j < msi_vectors; j++) {
+ readUpdate(fd, &posn, &newfd);
+ fds[posn][j] = newfd;
+ printf("%d.", fds[posn][j]);
+ }
+ printf("\n");
+
+ /* stop reading once i've read my own eventfds */
+ if (posn == count)
+ break;
+ }
+
+ return 0;
+}
+
+int sendKill(int fd, long const posn, size_t posn_len) {
+
+ struct cmsghdr *cmsg;
+ size_t msg_size = sizeof(int);
+ char control[CMSG_SPACE(msg_size)];
+ struct iovec iov[1];
+ size_t len;
+ struct msghdr msg = { 0, 0, iov, 1, control, sizeof control, 0 };
+
+ struct pollfd mypollfd;
+ int rv;
+
+ iov[0].iov_base = (void *) &posn;
+ iov[0].iov_len = posn_len;
+
+ // from cmsg(3)
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_len = 0;
+ msg.msg_controllen = cmsg->cmsg_len;
+
+ printf("Killing posn %ld\n", posn);
+
+ // check if the fd is dead or not
+ mypollfd.fd = fd;
+ mypollfd.events = POLLRDHUP;
+ mypollfd.revents = 0;
+
+ rv = poll(&mypollfd, 1, 0);
+
+ printf("rv is %d\n", rv);
+
+ if (rv == 0) {
+ len = sendmsg(fd, &msg, 0);
+ if (len == (size_t) (-1)) {
+ perror("sendmsg()");
+ return -1;
+ }
+ return (len == posn_len);
+ } else {
+ printf("already dead\n");
+ return 0;
+ }
+}
+
+int sendUpdate(int fd, long posn, size_t posn_len, int sendfd)
+{
+
+ struct cmsghdr *cmsg;
+ size_t msg_size = sizeof(int);
+ char control[CMSG_SPACE(msg_size)];
+ struct iovec iov[1];
+ size_t len;
+ struct msghdr msg = { 0, 0, iov, 1, control, sizeof control, 0 };
+
+ iov[0].iov_base = (void *) (&posn);
+ iov[0].iov_len = posn_len;
+
+ // from cmsg(3)
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(msg_size);
+ msg.msg_controllen = cmsg->cmsg_len;
+
+ memcpy((CMSG_DATA(cmsg)), &sendfd, msg_size);
+
+ len = sendmsg(fd, &msg, 0);
+ if (len == (size_t) (-1)) {
+ perror("sendmsg()");
+ return -1;
+ }
+
+ return (len == posn_len);
+
+}
+
+int sendPosition(int fd, long const posn)
+{
+ int rv;
+
+ rv = send(fd, &posn, sizeof(long), 0);
+ if (rv != sizeof(long)) {
+ fprintf(stderr, "error sending posn\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+int sendRights(int fd, long const count, size_t count_len, vmguest_t * Live_vms,
+ long msi_vectors)
+{
+ /* updates about new guests are sent one at a time */
+
+ long i, j;
+
+ for (i = 0; i <= count; i++) {
+ if (Live_vms[i].alive) {
+ for (j = 0; j < msi_vectors; j++) {
+ sendUpdate(Live_vms[count].sockfd, i, sizeof(long),
+ Live_vms[i].efd[j]);
+ }
+ }
+ }
+
+ return 0;
+
+}
diff --git a/contrib/ivshmem-server/send_scm.h b/contrib/ivshmem-server/send_scm.h
new file mode 100644
index 0000000..48c9a8d
--- /dev/null
+++ b/contrib/ivshmem-server/send_scm.h
@@ -0,0 +1,19 @@
+#ifndef SEND_SCM
+#define SEND_SCM
+
+struct vm_guest_conn {
+ int posn;
+ int sockfd;
+ int * efd;
+ int alive;
+};
+
+typedef struct vm_guest_conn vmguest_t;
+
+int readRights(int fd, long count, size_t count_len, int **fds, int msi_vectors);
+int sendRights(int fd, long const count, size_t count_len, vmguest_t *Live_vms, long msi_vectors);
+int readUpdate(int fd, long * posn, int * newfd);
+int sendUpdate(int fd, long const posn, size_t posn_len, int sendfd);
+int sendPosition(int fd, long const posn);
+int sendKill(int fd, long const posn, size_t posn_len);
+#endif
--
1.6.2.5
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