Re: [Qemu-devel] [PATCH v6 6/6] the stand-alone shared memory server for inter-VM shared memory

[Cam Macdonell]

On Mon, Jun 14, 2010 at 9:53 AM, Anthony Liguori <address@hidden> wrote:
> On 06/04/2010 04:45 PM, Cam Macdonell wrote:
>>
>> 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 |  353
>> +++++++++++++++++++++++++++++++
>>  contrib/ivshmem-server/send_scm.c       |  208 ++++++++++++++++++
>>  contrib/ivshmem-server/send_scm.h       |   19 ++
>>  5 files changed, 626 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..e0a7b98
>> --- /dev/null
>> +++ b/contrib/ivshmem-server/ivshmem_server.c
>>
>
> There's no licensing here.  I don't think this belongs in the qemu tree
> either to be honest.  If it were to be included, it ought to use all of the
> existing qemu infrastructure like the other qemu-* tools.

For the time being, I'm willing to leave it out and host it externally.

>
> Regards,
>
> Anthony Liguori
>
>> @@ -0,0 +1,353 @@
>> +/*
>> + * 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': {
>> +                    uint64_t value;
>> +                    char *ptr;
>> +
>> +                    value = strtoul(optarg,&ptr, 10);
>> +                    switch (*ptr) {
>> +                    case 0: case 'M': case 'm':
>> +                        value<<= 20;
>> +                        break;
>> +                    case 'G': case 'g':
>> +                        value<<= 30;
>> +                        break;
>> +                    default:
>> +                        fprintf(stderr, "qemu: invalid ram size: %s\n",
>> optarg);
>> +                        exit(1);
>> +                    }
>> +                    s->shm_size = value;
>> +                    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 (bytes)\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
>>
>
>