[PULL,02/31] contrib/rdmacm-mux: Add implementation of RDMA User MAD multiplexer

From: Yuval Shaia <yuval.shaia@oracle.com>

RDMA MAD kernel module (ibcm) disallow more than one MAD-agent for a
given MAD class.
This does not go hand-by-hand with qemu pvrdma device's requirements
where each VM is MAD agent.
Fix it by adding implementation of RDMA MAD multiplexer service which on
one hand register as a sole MAD agent with the kernel module and on the
other hand gives service to more than one VM.

Design Overview:
Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
----------------
A server process is registered to UMAD framework (for this to work the
rdma_cm kernel module needs to be unloaded) and creates a unix socket to
listen to incoming request from clients.
A client process (such as QEMU) connects to this unix socket and
registers with its own GID.

TX:
----
When client needs to send rdma_cm MAD message it construct it the same
way as without this multiplexer, i.e. creates a umad packet but this
time it writes its content to the socket instead of calling umad_send().
The server, upon receiving such a message fetch local_comm_id from it so
a context for this session can be maintain and relay the message to UMAD
layer by calling umad_send().

RX:
----
The server creates a worker thread to process incoming rdma_cm MAD
messages. When an incoming message arrived (umad_recv()) the server,
depending on the message type (attr_id) looks for target client by
either searching in gid->fd table or in local_comm_id->fd table. With
the extracted fd the server relays to incoming message to the client.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>

Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
---
 MAINTAINERS                      |   1 +
 Makefile                         |   3 +
 Makefile.objs                    |   1 +
 contrib/rdmacm-mux/Makefile.objs |   4 +
 contrib/rdmacm-mux/main.c        | 798 +++++++++++++++++++++++++++++++
 contrib/rdmacm-mux/rdmacm-mux.h  |  61 +++
 6 files changed, 868 insertions(+)
 create mode 100644 contrib/rdmacm-mux/Makefile.objs
 create mode 100644 contrib/rdmacm-mux/main.c
 create mode 100644 contrib/rdmacm-mux/rdmacm-mux.h

On Sat, 22 Dec 2018 11:50:07 +0200
Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:

> From: Yuval Shaia <yuval.shaia@oracle.com>
> 
> RDMA MAD kernel module (ibcm) disallow more than one MAD-agent for a
> given MAD class.
> This does not go hand-by-hand with qemu pvrdma device's requirements
> where each VM is MAD agent.
> Fix it by adding implementation of RDMA MAD multiplexer service which on
> one hand register as a sole MAD agent with the kernel module and on the
> other hand gives service to more than one VM.
> 
> Design Overview:
> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
> ----------------
> A server process is registered to UMAD framework (for this to work the
> rdma_cm kernel module needs to be unloaded) and creates a unix socket to
> listen to incoming request from clients.
> A client process (such as QEMU) connects to this unix socket and
> registers with its own GID.
> 
> TX:
> ----
> When client needs to send rdma_cm MAD message it construct it the same
> way as without this multiplexer, i.e. creates a umad packet but this
> time it writes its content to the socket instead of calling umad_send().
> The server, upon receiving such a message fetch local_comm_id from it so
> a context for this session can be maintain and relay the message to UMAD
> layer by calling umad_send().
> 
> RX:
> ----
> The server creates a worker thread to process incoming rdma_cm MAD
> messages. When an incoming message arrived (umad_recv()) the server,
> depending on the message type (attr_id) looks for target client by
> either searching in gid->fd table or in local_comm_id->fd table. With
> the extracted fd the server relays to incoming message to the client.
> 
> Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> 
> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> ---
>  MAINTAINERS                      |   1 +
>  Makefile                         |   3 +
>  Makefile.objs                    |   1 +
>  contrib/rdmacm-mux/Makefile.objs |   4 +
>  contrib/rdmacm-mux/main.c        | 798 +++++++++++++++++++++++++++++++
>  contrib/rdmacm-mux/rdmacm-mux.h  |  61 +++
>  6 files changed, 868 insertions(+)
>  create mode 100644 contrib/rdmacm-mux/Makefile.objs
>  create mode 100644 contrib/rdmacm-mux/main.c
>  create mode 100644 contrib/rdmacm-mux/rdmacm-mux.h

This commit breaks building with clang on Fedora 28 for me; I get a
bunch of

clang-6.0: error: -libumad: 'linker' input unused [-Werror,-Wunused-command-line-argument]

Explicitly passing --disable-pvrdma to configure disables the offending
code.

Let me know if you need more information.

> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3b31e07b26..856d379b0a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2412,6 +2412,7 @@ S: Maintained
>  F: hw/rdma/*
>  F: hw/rdma/vmw/*
>  F: docs/pvrdma.txt
> +F: contrib/rdmacm-mux/*
>  
>  Build and test automation
>  -------------------------
> diff --git a/Makefile b/Makefile
> index 038780c6d0..dd53965f77 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -362,6 +362,7 @@ dummy := $(call unnest-vars,, \
>                  elf2dmp-obj-y \
>                  ivshmem-client-obj-y \
>                  ivshmem-server-obj-y \
> +                rdmacm-mux-obj-y \
>                  libvhost-user-obj-y \
>                  vhost-user-scsi-obj-y \
>                  vhost-user-blk-obj-y \
> @@ -579,6 +580,8 @@ vhost-user-scsi$(EXESUF): $(vhost-user-scsi-obj-y) libvhost-user.a
>  	$(call LINK, $^)
>  vhost-user-blk$(EXESUF): $(vhost-user-blk-obj-y) libvhost-user.a
>  	$(call LINK, $^)
> +rdmacm-mux$(EXESUF): $(rdmacm-mux-obj-y) $(COMMON_LDADDS)
> +	$(call LINK, $^)
>  
>  module_block.h: $(SRC_PATH)/scripts/modules/module_block.py config-host.mak
>  	$(call quiet-command,$(PYTHON) $< $@ \
> diff --git a/Makefile.objs b/Makefile.objs
> index 56af0347d3..319f14d937 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -133,6 +133,7 @@ vhost-user-scsi.o-cflags := $(LIBISCSI_CFLAGS)
>  vhost-user-scsi.o-libs := $(LIBISCSI_LIBS)
>  vhost-user-scsi-obj-y = contrib/vhost-user-scsi/
>  vhost-user-blk-obj-y = contrib/vhost-user-blk/
> +rdmacm-mux-obj-y = contrib/rdmacm-mux/
>  
>  ######################################################################
>  trace-events-subdirs =
> diff --git a/contrib/rdmacm-mux/Makefile.objs b/contrib/rdmacm-mux/Makefile.objs
> new file mode 100644
> index 0000000000..be3eacb6f7
> --- /dev/null
> +++ b/contrib/rdmacm-mux/Makefile.objs
> @@ -0,0 +1,4 @@
> +ifdef CONFIG_PVRDMA
> +CFLAGS += -libumad -Wno-format-truncation
> +rdmacm-mux-obj-y = main.o
> +endif
> diff --git a/contrib/rdmacm-mux/main.c b/contrib/rdmacm-mux/main.c
> new file mode 100644
> index 0000000000..835a7f9214
> --- /dev/null
> +++ b/contrib/rdmacm-mux/main.c
> @@ -0,0 +1,798 @@
> +/*
> + * QEMU paravirtual RDMA - rdmacm-mux implementation
> + *
> + * Copyright (C) 2018 Oracle
> + * Copyright (C) 2018 Red Hat Inc
> + *
> + * Authors:
> + *     Yuval Shaia <yuval.shaia@oracle.com>
> + *     Marcel Apfelbaum <marcel@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "sys/poll.h"
> +#include "sys/ioctl.h"
> +#include "pthread.h"
> +#include "syslog.h"
> +
> +#include "infiniband/verbs.h"
> +#include "infiniband/umad.h"
> +#include "infiniband/umad_types.h"
> +#include "infiniband/umad_sa.h"
> +#include "infiniband/umad_cm.h"
> +
> +#include "rdmacm-mux.h"
> +
> +#define SCALE_US 1000
> +#define COMMID_TTL 2 /* How many SCALE_US a context of MAD session is saved */
> +#define SLEEP_SECS 5 /* This is used both in poll() and thread */
> +#define SERVER_LISTEN_BACKLOG 10
> +#define MAX_CLIENTS 4096
> +#define MAD_RMPP_VERSION 0
> +#define MAD_METHOD_MASK0 0x8
> +
> +#define IB_USER_MAD_LONGS_PER_METHOD_MASK (128 / (8 * sizeof(long)))
> +
> +#define CM_REQ_DGID_POS      80
> +#define CM_SIDR_REQ_DGID_POS 44
> +
> +/* The below can be override by command line parameter */
> +#define UNIX_SOCKET_PATH "/var/run/rdmacm-mux"
> +#define RDMA_PORT_NUM 1
> +
> +typedef struct RdmaCmServerArgs {
> +    char unix_socket_path[PATH_MAX];
> +    char rdma_dev_name[NAME_MAX];
> +    int rdma_port_num;
> +} RdmaCMServerArgs;
> +
> +typedef struct CommId2FdEntry {
> +    int fd;
> +    int ttl; /* Initialized to 2, decrement each timeout, entry delete when 0 */
> +    __be64 gid_ifid;
> +} CommId2FdEntry;
> +
> +typedef struct RdmaCmUMadAgent {
> +    int port_id;
> +    int agent_id;
> +    GHashTable *gid2fd; /* Used to find fd of a given gid */
> +    GHashTable *commid2fd; /* Used to find fd on of a given comm_id */
> +} RdmaCmUMadAgent;
> +
> +typedef struct RdmaCmServer {
> +    bool run;
> +    RdmaCMServerArgs args;
> +    struct pollfd fds[MAX_CLIENTS];
> +    int nfds;
> +    RdmaCmUMadAgent umad_agent;
> +    pthread_t umad_recv_thread;
> +    pthread_rwlock_t lock;
> +} RdmaCMServer;
> +
> +static RdmaCMServer server = {0};
> +
> +static void usage(const char *progname)
> +{
> +    printf("Usage: %s [OPTION]...\n"
> +           "Start a RDMA-CM multiplexer\n"
> +           "\n"
> +           "\t-h                    Show this help\n"
> +           "\t-d rdma-device-name   Name of RDMA device to register with\n"
> +           "\t-s unix-socket-path   Path to unix socket to listen on (default %s)\n"
> +           "\t-p rdma-device-port   Port number of RDMA device to register with (default %d)\n",
> +           progname, UNIX_SOCKET_PATH, RDMA_PORT_NUM);
> +}
> +
> +static void help(const char *progname)
> +{
> +    fprintf(stderr, "Try '%s -h' for more information.\n", progname);
> +}
> +
> +static void parse_args(int argc, char *argv[])
> +{
> +    int c;
> +    char unix_socket_path[PATH_MAX];
> +
> +    strcpy(server.args.rdma_dev_name, "");
> +    strcpy(unix_socket_path, UNIX_SOCKET_PATH);
> +    server.args.rdma_port_num = RDMA_PORT_NUM;
> +
> +    while ((c = getopt(argc, argv, "hs:d:p:")) != -1) {
> +        switch (c) {
> +        case 'h':
> +            usage(argv[0]);
> +            exit(0);
> +
> +        case 'd':
> +            strncpy(server.args.rdma_dev_name, optarg, NAME_MAX - 1);
> +            break;
> +
> +        case 's':
> +            /* This is temporary, final name will build below */
> +            strncpy(unix_socket_path, optarg, PATH_MAX);
> +            break;
> +
> +        case 'p':
> +            server.args.rdma_port_num = atoi(optarg);
> +            break;
> +
> +        default:
> +            help(argv[0]);
> +            exit(1);
> +        }
> +    }
> +
> +    if (!strcmp(server.args.rdma_dev_name, "")) {
> +        fprintf(stderr, "Missing RDMA device name\n");
> +        help(argv[0]);
> +        exit(1);
> +    }
> +
> +    /* Build unique unix-socket file name */
> +    snprintf(server.args.unix_socket_path, PATH_MAX, "%s-%s-%d",
> +             unix_socket_path, server.args.rdma_dev_name,
> +             server.args.rdma_port_num);
> +
> +    syslog(LOG_INFO, "unix_socket_path=%s", server.args.unix_socket_path);
> +    syslog(LOG_INFO, "rdma-device-name=%s", server.args.rdma_dev_name);
> +    syslog(LOG_INFO, "rdma-device-port=%d", server.args.rdma_port_num);
> +}
> +
> +static void hash_tbl_alloc(void)
> +{
> +
> +    server.umad_agent.gid2fd = g_hash_table_new_full(g_int64_hash,
> +                                                     g_int64_equal,
> +                                                     g_free, g_free);
> +    server.umad_agent.commid2fd = g_hash_table_new_full(g_int_hash,
> +                                                        g_int_equal,
> +                                                        g_free, g_free);
> +}
> +
> +static void hash_tbl_free(void)
> +{
> +    if (server.umad_agent.commid2fd) {
> +        g_hash_table_destroy(server.umad_agent.commid2fd);
> +    }
> +    if (server.umad_agent.gid2fd) {
> +        g_hash_table_destroy(server.umad_agent.gid2fd);
> +    }
> +}
> +
> +
> +static int _hash_tbl_search_fd_by_ifid(__be64 *gid_ifid)
> +{
> +    int *fd;
> +
> +    fd = g_hash_table_lookup(server.umad_agent.gid2fd, gid_ifid);
> +    if (!fd) {
> +        /* Let's try IPv4 */
> +        *gid_ifid |= 0x00000000ffff0000;
> +        fd = g_hash_table_lookup(server.umad_agent.gid2fd, gid_ifid);
> +    }
> +
> +    return fd ? *fd : 0;
> +}
> +
> +static int hash_tbl_search_fd_by_ifid(int *fd, __be64 *gid_ifid)
> +{
> +    pthread_rwlock_rdlock(&server.lock);
> +    *fd = _hash_tbl_search_fd_by_ifid(gid_ifid);
> +    pthread_rwlock_unlock(&server.lock);
> +
> +    if (!fd) {
> +        syslog(LOG_WARNING, "Can't find matching for ifid 0x%llx\n", *gid_ifid);
> +        return -ENOENT;
> +    }
> +
> +    return 0;
> +}
> +
> +static int hash_tbl_search_fd_by_comm_id(uint32_t comm_id, int *fd,
> +                                         __be64 *gid_idid)
> +{
> +    CommId2FdEntry *fde;
> +
> +    pthread_rwlock_rdlock(&server.lock);
> +    fde = g_hash_table_lookup(server.umad_agent.commid2fd, &comm_id);
> +    pthread_rwlock_unlock(&server.lock);
> +
> +    if (!fde) {
> +        syslog(LOG_WARNING, "Can't find matching for comm_id 0x%x\n", comm_id);
> +        return -ENOENT;
> +    }
> +
> +    *fd = fde->fd;
> +    *gid_idid = fde->gid_ifid;
> +
> +    return 0;
> +}
> +
> +static RdmaCmMuxErrCode add_fd_ifid_pair(int fd, __be64 gid_ifid)
> +{
> +    int fd1;
> +
> +    pthread_rwlock_wrlock(&server.lock);
> +
> +    fd1 = _hash_tbl_search_fd_by_ifid(&gid_ifid);
> +    if (fd1) { /* record already exist - an error */
> +        pthread_rwlock_unlock(&server.lock);
> +        return fd == fd1 ? RDMACM_MUX_ERR_CODE_EEXIST :
> +                           RDMACM_MUX_ERR_CODE_EACCES;
> +    }
> +
> +    g_hash_table_insert(server.umad_agent.gid2fd, g_memdup(&gid_ifid,
> +                        sizeof(gid_ifid)), g_memdup(&fd, sizeof(fd)));
> +
> +    pthread_rwlock_unlock(&server.lock);
> +
> +    syslog(LOG_INFO, "0x%lx registered on socket %d",
> +           be64toh((uint64_t)gid_ifid), fd);
> +
> +    return RDMACM_MUX_ERR_CODE_OK;
> +}
> +
> +static RdmaCmMuxErrCode delete_fd_ifid_pair(int fd, __be64 gid_ifid)
> +{
> +    int fd1;
> +
> +    pthread_rwlock_wrlock(&server.lock);
> +
> +    fd1 = _hash_tbl_search_fd_by_ifid(&gid_ifid);
> +    if (!fd1) { /* record not exist - an error */
> +        pthread_rwlock_unlock(&server.lock);
> +        return RDMACM_MUX_ERR_CODE_ENOTFOUND;
> +    }
> +
> +    g_hash_table_remove(server.umad_agent.gid2fd, g_memdup(&gid_ifid,
> +                        sizeof(gid_ifid)));
> +    pthread_rwlock_unlock(&server.lock);
> +
> +    syslog(LOG_INFO, "0x%lx unregistered on socket %d",
> +           be64toh((uint64_t)gid_ifid), fd);
> +
> +    return RDMACM_MUX_ERR_CODE_OK;
> +}
> +
> +static void hash_tbl_save_fd_comm_id_pair(int fd, uint32_t comm_id,
> +                                          uint64_t gid_ifid)
> +{
> +    CommId2FdEntry fde = {fd, COMMID_TTL, gid_ifid};
> +
> +    pthread_rwlock_wrlock(&server.lock);
> +    g_hash_table_insert(server.umad_agent.commid2fd,
> +                        g_memdup(&comm_id, sizeof(comm_id)),
> +                        g_memdup(&fde, sizeof(fde)));
> +    pthread_rwlock_unlock(&server.lock);
> +}
> +
> +static gboolean remove_old_comm_ids(gpointer key, gpointer value,
> +                                    gpointer user_data)
> +{
> +    CommId2FdEntry *fde = (CommId2FdEntry *)value;
> +
> +    return !fde->ttl--;
> +}
> +
> +static gboolean remove_entry_from_gid2fd(gpointer key, gpointer value,
> +                                         gpointer user_data)
> +{
> +    if (*(int *)value == *(int *)user_data) {
> +        syslog(LOG_INFO, "0x%lx unregistered on socket %d",
> +               be64toh(*(uint64_t *)key), *(int *)value);
> +        return true;
> +    }
> +
> +    return false;
> +}
> +
> +static void hash_tbl_remove_fd_ifid_pair(int fd)
> +{
> +    pthread_rwlock_wrlock(&server.lock);
> +    g_hash_table_foreach_remove(server.umad_agent.gid2fd,
> +                                remove_entry_from_gid2fd, (gpointer)&fd);
> +    pthread_rwlock_unlock(&server.lock);
> +}
> +
> +static int get_fd(const char *mad, int *fd, __be64 *gid_ifid)
> +{
> +    struct umad_hdr *hdr = (struct umad_hdr *)mad;
> +    char *data = (char *)hdr + sizeof(*hdr);
> +    int32_t comm_id = 0;
> +    uint16_t attr_id = be16toh(hdr->attr_id);
> +    int rc = 0;
> +
> +    switch (attr_id) {
> +    case UMAD_CM_ATTR_REQ:
> +        memcpy(gid_ifid, data + CM_REQ_DGID_POS, sizeof(*gid_ifid));
> +        rc = hash_tbl_search_fd_by_ifid(fd, gid_ifid);
> +        break;
> +
> +    case UMAD_CM_ATTR_SIDR_REQ:
> +        memcpy(gid_ifid, data + CM_SIDR_REQ_DGID_POS, sizeof(*gid_ifid));
> +        rc = hash_tbl_search_fd_by_ifid(fd, gid_ifid);
> +        break;
> +
> +    case UMAD_CM_ATTR_REP:
> +        /* Fall through */
> +    case UMAD_CM_ATTR_REJ:
> +        /* Fall through */
> +    case UMAD_CM_ATTR_DREQ:
> +        /* Fall through */
> +    case UMAD_CM_ATTR_DREP:
> +        /* Fall through */
> +    case UMAD_CM_ATTR_RTU:
> +        data += sizeof(comm_id);
> +        /* Fall through */
> +    case UMAD_CM_ATTR_SIDR_REP:
> +        memcpy(&comm_id, data, sizeof(comm_id));
> +        if (comm_id) {
> +            rc = hash_tbl_search_fd_by_comm_id(comm_id, fd, gid_ifid);
> +        }
> +        break;
> +
> +    default:
> +        rc = -EINVAL;
> +        syslog(LOG_WARNING, "Unsupported attr_id 0x%x\n", attr_id);
> +    }
> +
> +    syslog(LOG_DEBUG, "mad_to_vm: %d 0x%x 0x%x\n", *fd, attr_id, comm_id);
> +
> +    return rc;
> +}
> +
> +static void *umad_recv_thread_func(void *args)
> +{
> +    int rc;
> +    RdmaCmMuxMsg msg = {0};
> +    int fd = -2;
> +
> +    msg.hdr.msg_type = RDMACM_MUX_MSG_TYPE_REQ;
> +    msg.hdr.op_code = RDMACM_MUX_OP_CODE_MAD;
> +
> +    while (server.run) {
> +        do {
> +            msg.umad_len = sizeof(msg.umad.mad);
> +            rc = umad_recv(server.umad_agent.port_id, &msg.umad, &msg.umad_len,
> +                           SLEEP_SECS * SCALE_US);
> +            if ((rc == -EIO) || (rc == -EINVAL)) {
> +                syslog(LOG_CRIT, "Fatal error while trying to read MAD");
> +            }
> +
> +            if (rc == -ETIMEDOUT) {
> +                g_hash_table_foreach_remove(server.umad_agent.commid2fd,
> +                                            remove_old_comm_ids, NULL);
> +            }
> +        } while (rc && server.run);
> +
> +        if (server.run) {
> +            rc = get_fd(msg.umad.mad, &fd, &msg.hdr.sgid.global.interface_id);
> +            if (rc) {
> +                continue;
> +            }
> +
> +            send(fd, &msg, sizeof(msg), 0);
> +        }
> +    }
> +
> +    return NULL;
> +}
> +
> +static int read_and_process(int fd)
> +{
> +    int rc;
> +    RdmaCmMuxMsg msg = {0};
> +    struct umad_hdr *hdr;
> +    uint32_t *comm_id = 0;
> +    uint16_t attr_id;
> +
> +    rc = recv(fd, &msg, sizeof(msg), 0);
> +    syslog(LOG_DEBUG, "Socket %d, recv %d\n", fd, rc);
> +
> +    if (rc < 0 && errno != EWOULDBLOCK) {
> +        syslog(LOG_ERR, "Fail to read from socket %d\n", fd);
> +        return -EIO;
> +    }
> +
> +    if (!rc) {
> +        syslog(LOG_ERR, "Fail to read from socket %d\n", fd);
> +        return -EPIPE;
> +    }
> +
> +    if (msg.hdr.msg_type != RDMACM_MUX_MSG_TYPE_REQ) {
> +        syslog(LOG_WARNING, "Got non-request message (%d) from socket %d\n",
> +               msg.hdr.msg_type, fd);
> +        return -EPERM;
> +    }
> +
> +    switch (msg.hdr.op_code) {
> +    case RDMACM_MUX_OP_CODE_REG:
> +        rc = add_fd_ifid_pair(fd, msg.hdr.sgid.global.interface_id);
> +        break;
> +
> +    case RDMACM_MUX_OP_CODE_UNREG:
> +        rc = delete_fd_ifid_pair(fd, msg.hdr.sgid.global.interface_id);
> +        break;
> +
> +    case RDMACM_MUX_OP_CODE_MAD:
> +        /* If this is REQ or REP then store the pair comm_id,fd to be later
> +         * used for other messages where gid is unknown */
> +        hdr = (struct umad_hdr *)msg.umad.mad;
> +        attr_id = be16toh(hdr->attr_id);
> +        if ((attr_id == UMAD_CM_ATTR_REQ) || (attr_id == UMAD_CM_ATTR_DREQ) ||
> +            (attr_id == UMAD_CM_ATTR_SIDR_REQ) ||
> +            (attr_id == UMAD_CM_ATTR_REP) || (attr_id == UMAD_CM_ATTR_DREP)) {
> +            comm_id = (uint32_t *)(msg.umad.mad + sizeof(*hdr));
> +            hash_tbl_save_fd_comm_id_pair(fd, *comm_id,
> +                                          msg.hdr.sgid.global.interface_id);
> +        }
> +
> +        syslog(LOG_DEBUG, "vm_to_mad: %d 0x%x 0x%x\n", fd, attr_id,
> +               comm_id ? *comm_id : 0);
> +        rc = umad_send(server.umad_agent.port_id, server.umad_agent.agent_id,
> +                       &msg.umad, msg.umad_len, 1, 0);
> +        if (rc) {
> +            syslog(LOG_ERR,
> +                  "Fail to send MAD message (0x%x) from socket %d, err=%d",
> +                  attr_id, fd, rc);
> +        }
> +        break;
> +
> +    default:
> +        syslog(LOG_ERR, "Got invalid op_code (%d) from socket %d",
> +               msg.hdr.msg_type, fd);
> +        rc = RDMACM_MUX_ERR_CODE_EINVAL;
> +    }
> +
> +    msg.hdr.msg_type = RDMACM_MUX_MSG_TYPE_RESP;
> +    msg.hdr.err_code = rc;
> +    rc = send(fd, &msg, sizeof(msg), 0);
> +
> +    return rc == sizeof(msg) ? 0 : -EPIPE;
> +}
> +
> +static int accept_all(void)
> +{
> +    int fd, rc = 0;;
> +
> +    pthread_rwlock_wrlock(&server.lock);
> +
> +    do {
> +        if ((server.nfds + 1) > MAX_CLIENTS) {
> +            syslog(LOG_WARNING, "Too many clients (%d)", server.nfds);
> +            rc = -EIO;
> +            goto out;
> +        }
> +
> +        fd = accept(server.fds[0].fd, NULL, NULL);
> +        if (fd < 0) {
> +            if (errno != EWOULDBLOCK) {
> +                syslog(LOG_WARNING, "accept() failed");
> +                rc = -EIO;
> +                goto out;
> +            }
> +            break;
> +        }
> +
> +        syslog(LOG_INFO, "Client connected on socket %d\n", fd);
> +        server.fds[server.nfds].fd = fd;
> +        server.fds[server.nfds].events = POLLIN;
> +        server.nfds++;
> +    } while (fd != -1);
> +
> +out:
> +    pthread_rwlock_unlock(&server.lock);
> +    return rc;
> +}
> +
> +static void compress_fds(void)
> +{
> +    int i, j;
> +    int closed = 0;
> +
> +    pthread_rwlock_wrlock(&server.lock);
> +
> +    for (i = 1; i < server.nfds; i++) {
> +        if (!server.fds[i].fd) {
> +            closed++;
> +            for (j = i; j < server.nfds - 1; j++) {
> +                server.fds[j] = server.fds[j + 1];
> +            }
> +        }
> +    }
> +
> +    server.nfds -= closed;
> +
> +    pthread_rwlock_unlock(&server.lock);
> +}
> +
> +static void close_fd(int idx)
> +{
> +    close(server.fds[idx].fd);
> +    syslog(LOG_INFO, "Socket %d closed\n", server.fds[idx].fd);
> +    hash_tbl_remove_fd_ifid_pair(server.fds[idx].fd);
> +    server.fds[idx].fd = 0;
> +}
> +
> +static void run(void)
> +{
> +    int rc, nfds, i;
> +    bool compress = false;
> +
> +    syslog(LOG_INFO, "Service started");
> +
> +    while (server.run) {
> +        rc = poll(server.fds, server.nfds, SLEEP_SECS * SCALE_US);
> +        if (rc < 0) {
> +            if (errno != EINTR) {
> +                syslog(LOG_WARNING, "poll() failed");
> +            }
> +            continue;
> +        }
> +
> +        if (rc == 0) {
> +            continue;
> +        }
> +
> +        nfds = server.nfds;
> +        for (i = 0; i < nfds; i++) {
> +            syslog(LOG_DEBUG, "pollfd[%d]: revents 0x%x, events 0x%x\n", i,
> +                   server.fds[i].revents, server.fds[i].events);
> +            if (server.fds[i].revents == 0) {
> +                continue;
> +            }
> +
> +            if (server.fds[i].revents != POLLIN) {
> +                if (i == 0) {
> +                    syslog(LOG_NOTICE, "Unexpected poll() event (0x%x)\n",
> +                           server.fds[i].revents);
> +                } else {
> +                    close_fd(i);
> +                    compress = true;
> +                }
> +                continue;
> +            }
> +
> +            if (i == 0) {
> +                rc = accept_all();
> +                if (rc) {
> +                    continue;
> +                }
> +            } else {
> +                rc = read_and_process(server.fds[i].fd);
> +                if (rc) {
> +                    close_fd(i);
> +                    compress = true;
> +                }
> +            }
> +        }
> +
> +        if (compress) {
> +            compress = false;
> +            compress_fds();
> +        }
> +    }
> +}
> +
> +static void fini_listener(void)
> +{
> +    int i;
> +
> +    if (server.fds[0].fd <= 0) {
> +        return;
> +    }
> +
> +    for (i = server.nfds - 1; i >= 0; i--) {
> +        if (server.fds[i].fd) {
> +            close(server.fds[i].fd);
> +        }
> +    }
> +
> +    unlink(server.args.unix_socket_path);
> +}
> +
> +static void fini_umad(void)
> +{
> +    if (server.umad_agent.agent_id) {
> +        umad_unregister(server.umad_agent.port_id, server.umad_agent.agent_id);
> +    }
> +
> +    if (server.umad_agent.port_id) {
> +        umad_close_port(server.umad_agent.port_id);
> +    }
> +
> +    hash_tbl_free();
> +}
> +
> +static void fini(void)
> +{
> +    if (server.umad_recv_thread) {
> +        pthread_join(server.umad_recv_thread, NULL);
> +        server.umad_recv_thread = 0;
> +    }
> +    fini_umad();
> +    fini_listener();
> +    pthread_rwlock_destroy(&server.lock);
> +
> +    syslog(LOG_INFO, "Service going down");
> +}
> +
> +static int init_listener(void)
> +{
> +    struct sockaddr_un sun;
> +    int rc, on = 1;
> +
> +    server.fds[0].fd = socket(AF_UNIX, SOCK_STREAM, 0);
> +    if (server.fds[0].fd < 0) {
> +        syslog(LOG_ALERT, "socket() failed");
> +        return -EIO;
> +    }
> +
> +    rc = setsockopt(server.fds[0].fd, SOL_SOCKET, SO_REUSEADDR, (char *)&on,
> +                    sizeof(on));
> +    if (rc < 0) {
> +        syslog(LOG_ALERT, "setsockopt() failed");
> +        rc = -EIO;
> +        goto err;
> +    }
> +
> +    rc = ioctl(server.fds[0].fd, FIONBIO, (char *)&on);
> +    if (rc < 0) {
> +        syslog(LOG_ALERT, "ioctl() failed");
> +        rc = -EIO;
> +        goto err;
> +    }
> +
> +    if (strlen(server.args.unix_socket_path) >= sizeof(sun.sun_path)) {
> +        syslog(LOG_ALERT,
> +               "Invalid unix_socket_path, size must be less than %ld\n",
> +               sizeof(sun.sun_path));
> +        rc = -EINVAL;
> +        goto err;
> +    }
> +
> +    sun.sun_family = AF_UNIX;
> +    rc = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
> +                  server.args.unix_socket_path);
> +    if (rc < 0 || rc >= sizeof(sun.sun_path)) {
> +        syslog(LOG_ALERT, "Could not copy unix socket path\n");
> +        rc = -EINVAL;
> +        goto err;
> +    }
> +
> +    rc = bind(server.fds[0].fd, (struct sockaddr *)&sun, sizeof(sun));
> +    if (rc < 0) {
> +        syslog(LOG_ALERT, "bind() failed");
> +        rc = -EIO;
> +        goto err;
> +    }
> +
> +    rc = listen(server.fds[0].fd, SERVER_LISTEN_BACKLOG);
> +    if (rc < 0) {
> +        syslog(LOG_ALERT, "listen() failed");
> +        rc = -EIO;
> +        goto err;
> +    }
> +
> +    server.fds[0].events = POLLIN;
> +    server.nfds = 1;
> +    server.run = true;
> +
> +    return 0;
> +
> +err:
> +    close(server.fds[0].fd);
> +    return rc;
> +}
> +
> +static int init_umad(void)
> +{
> +    long method_mask[IB_USER_MAD_LONGS_PER_METHOD_MASK];
> +
> +    server.umad_agent.port_id = umad_open_port(server.args.rdma_dev_name,
> +                                               server.args.rdma_port_num);
> +
> +    if (server.umad_agent.port_id < 0) {
> +        syslog(LOG_WARNING, "umad_open_port() failed");
> +        return -EIO;
> +    }
> +
> +    memset(&method_mask, 0, sizeof(method_mask));
> +    method_mask[0] = MAD_METHOD_MASK0;
> +    server.umad_agent.agent_id = umad_register(server.umad_agent.port_id,
> +                                               UMAD_CLASS_CM,
> +                                               UMAD_SA_CLASS_VERSION,
> +                                               MAD_RMPP_VERSION, method_mask);
> +    if (server.umad_agent.agent_id < 0) {
> +        syslog(LOG_WARNING, "umad_register() failed");
> +        return -EIO;
> +    }
> +
> +    hash_tbl_alloc();
> +
> +    return 0;
> +}
> +
> +static void signal_handler(int sig, siginfo_t *siginfo, void *context)
> +{
> +    static bool warned;
> +
> +    /* Prevent stop if clients are connected */
> +    if (server.nfds != 1) {
> +        if (!warned) {
> +            syslog(LOG_WARNING,
> +                   "Can't stop while active client exist, resend SIGINT to overid");
> +            warned = true;
> +            return;
> +        }
> +    }
> +
> +    if (sig == SIGINT) {
> +        server.run = false;
> +        fini();
> +    }
> +
> +    exit(0);
> +}
> +
> +static int init(void)
> +{
> +    int rc;
> +    struct sigaction sig = {0};
> +
> +    rc = init_listener();
> +    if (rc) {
> +        return rc;
> +    }
> +
> +    rc = init_umad();
> +    if (rc) {
> +        return rc;
> +    }
> +
> +    pthread_rwlock_init(&server.lock, 0);
> +
> +    rc = pthread_create(&server.umad_recv_thread, NULL, umad_recv_thread_func,
> +                        NULL);
> +    if (rc) {
> +        syslog(LOG_ERR, "Fail to create UMAD receiver thread (%d)\n", rc);
> +        return rc;
> +    }
> +
> +    sig.sa_sigaction = &signal_handler;
> +    sig.sa_flags = SA_SIGINFO;
> +    rc = sigaction(SIGINT, &sig, NULL);
> +    if (rc < 0) {
> +        syslog(LOG_ERR, "Fail to install SIGINT handler (%d)\n", errno);
> +        return rc;
> +    }
> +
> +    return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +    int rc;
> +
> +    memset(&server, 0, sizeof(server));
> +
> +    parse_args(argc, argv);
> +
> +    rc = init();
> +    if (rc) {
> +        syslog(LOG_ERR, "Fail to initialize server (%d)\n", rc);
> +        rc = -EAGAIN;
> +        goto out;
> +    }
> +
> +    run();
> +
> +out:
> +    fini();
> +
> +    return rc;
> +}
> diff --git a/contrib/rdmacm-mux/rdmacm-mux.h b/contrib/rdmacm-mux/rdmacm-mux.h
> new file mode 100644
> index 0000000000..942a802c47
> --- /dev/null
> +++ b/contrib/rdmacm-mux/rdmacm-mux.h
> @@ -0,0 +1,61 @@
> +/*
> + * QEMU paravirtual RDMA - rdmacm-mux declarations
> + *
> + * Copyright (C) 2018 Oracle
> + * Copyright (C) 2018 Red Hat Inc
> + *
> + * Authors:
> + *     Yuval Shaia <yuval.shaia@oracle.com>
> + *     Marcel Apfelbaum <marcel@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#ifndef RDMACM_MUX_H
> +#define RDMACM_MUX_H
> +
> +#include "linux/if.h"
> +#include "infiniband/verbs.h"
> +#include "infiniband/umad.h"
> +#include "rdma/rdma_user_cm.h"
> +
> +typedef enum RdmaCmMuxMsgType {
> +    RDMACM_MUX_MSG_TYPE_REQ   = 0,
> +    RDMACM_MUX_MSG_TYPE_RESP  = 1,
> +} RdmaCmMuxMsgType;
> +
> +typedef enum RdmaCmMuxOpCode {
> +    RDMACM_MUX_OP_CODE_REG   = 0,
> +    RDMACM_MUX_OP_CODE_UNREG = 1,
> +    RDMACM_MUX_OP_CODE_MAD   = 2,
> +} RdmaCmMuxOpCode;
> +
> +typedef enum RdmaCmMuxErrCode {
> +    RDMACM_MUX_ERR_CODE_OK        = 0,
> +    RDMACM_MUX_ERR_CODE_EINVAL    = 1,
> +    RDMACM_MUX_ERR_CODE_EEXIST    = 2,
> +    RDMACM_MUX_ERR_CODE_EACCES    = 3,
> +    RDMACM_MUX_ERR_CODE_ENOTFOUND = 4,
> +} RdmaCmMuxErrCode;
> +
> +typedef struct RdmaCmMuxHdr {
> +    RdmaCmMuxMsgType msg_type;
> +    RdmaCmMuxOpCode op_code;
> +    union ibv_gid sgid;
> +    RdmaCmMuxErrCode err_code;
> +} RdmaCmUHdr;
> +
> +typedef struct RdmaCmUMad {
> +    struct ib_user_mad hdr;
> +    char mad[RDMA_MAX_PRIVATE_DATA];
> +} RdmaCmUMad;
> +
> +typedef struct RdmaCmMuxMsg {
> +    RdmaCmUHdr hdr;
> +    int umad_len;
> +    RdmaCmUMad umad;
> +} RdmaCmMuxMsg;
> +
> +#endif

On 1/3/19 12:34 PM, Cornelia Huck wrote:
> On Sat, 22 Dec 2018 11:50:07 +0200
> Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
>
>> From: Yuval Shaia <yuval.shaia@oracle.com>
>>
>> RDMA MAD kernel module (ibcm) disallow more than one MAD-agent for a
>> given MAD class.
>> This does not go hand-by-hand with qemu pvrdma device's requirements
>> where each VM is MAD agent.
>> Fix it by adding implementation of RDMA MAD multiplexer service which on
>> one hand register as a sole MAD agent with the kernel module and on the
>> other hand gives service to more than one VM.
>>
>> Design Overview:
>> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
>> ----------------
>> A server process is registered to UMAD framework (for this to work the
>> rdma_cm kernel module needs to be unloaded) and creates a unix socket to
>> listen to incoming request from clients.
>> A client process (such as QEMU) connects to this unix socket and
>> registers with its own GID.
>>
>> TX:
>> ----
>> When client needs to send rdma_cm MAD message it construct it the same
>> way as without this multiplexer, i.e. creates a umad packet but this
>> time it writes its content to the socket instead of calling umad_send().
>> The server, upon receiving such a message fetch local_comm_id from it so
>> a context for this session can be maintain and relay the message to UMAD
>> layer by calling umad_send().
>>
>> RX:
>> ----
>> The server creates a worker thread to process incoming rdma_cm MAD
>> messages. When an incoming message arrived (umad_recv()) the server,
>> depending on the message type (attr_id) looks for target client by
>> either searching in gid->fd table or in local_comm_id->fd table. With
>> the extracted fd the server relays to incoming message to the client.
>>
>> Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
>> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
>> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
>>
>> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
>> ---
>>   MAINTAINERS                      |   1 +
>>   Makefile                         |   3 +
>>   Makefile.objs                    |   1 +
>>   contrib/rdmacm-mux/Makefile.objs |   4 +
>>   contrib/rdmacm-mux/main.c        | 798 +++++++++++++++++++++++++++++++
>>   contrib/rdmacm-mux/rdmacm-mux.h  |  61 +++
>>   6 files changed, 868 insertions(+)
>>   create mode 100644 contrib/rdmacm-mux/Makefile.objs
>>   create mode 100644 contrib/rdmacm-mux/main.c
>>   create mode 100644 contrib/rdmacm-mux/rdmacm-mux.h
> This commit breaks building with clang on Fedora 28 for me; I get a
> bunch of
>

Hi Cornelia,
Thanks for spotting the issue.

> clang-6.0: error: -libumad: 'linker' input unused [-Werror,-Wunused-command-line-argument]

Is really strange, the rdma-mux is part of the contrib directory
and is not even compiled by default.

> Explicitly passing --disable-pvrdma to configure disables the offending
> code.
>
> Let me know if you need more information.

Can you please send the exact steps you are using to configure and 
compile QEMU,
are you compiling on a x86 machine?

Thanks,
Marcel

On Mon, 7 Jan 2019 19:28:10 +0200
Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:

> On 1/3/19 12:34 PM, Cornelia Huck wrote:
> > On Sat, 22 Dec 2018 11:50:07 +0200
> > Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
> >  
> >> From: Yuval Shaia <yuval.shaia@oracle.com>
> >>
> >> RDMA MAD kernel module (ibcm) disallow more than one MAD-agent for a
> >> given MAD class.
> >> This does not go hand-by-hand with qemu pvrdma device's requirements
> >> where each VM is MAD agent.
> >> Fix it by adding implementation of RDMA MAD multiplexer service which on
> >> one hand register as a sole MAD agent with the kernel module and on the
> >> other hand gives service to more than one VM.
> >>
> >> Design Overview:
> >> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
> >> ----------------
> >> A server process is registered to UMAD framework (for this to work the
> >> rdma_cm kernel module needs to be unloaded) and creates a unix socket to
> >> listen to incoming request from clients.
> >> A client process (such as QEMU) connects to this unix socket and
> >> registers with its own GID.
> >>
> >> TX:
> >> ----
> >> When client needs to send rdma_cm MAD message it construct it the same
> >> way as without this multiplexer, i.e. creates a umad packet but this
> >> time it writes its content to the socket instead of calling umad_send().
> >> The server, upon receiving such a message fetch local_comm_id from it so
> >> a context for this session can be maintain and relay the message to UMAD
> >> layer by calling umad_send().
> >>
> >> RX:
> >> ----
> >> The server creates a worker thread to process incoming rdma_cm MAD
> >> messages. When an incoming message arrived (umad_recv()) the server,
> >> depending on the message type (attr_id) looks for target client by
> >> either searching in gid->fd table or in local_comm_id->fd table. With
> >> the extracted fd the server relays to incoming message to the client.
> >>
> >> Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
> >> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
> >> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> >>
> >> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> >> ---
> >>   MAINTAINERS                      |   1 +
> >>   Makefile                         |   3 +
> >>   Makefile.objs                    |   1 +
> >>   contrib/rdmacm-mux/Makefile.objs |   4 +
> >>   contrib/rdmacm-mux/main.c        | 798 +++++++++++++++++++++++++++++++
> >>   contrib/rdmacm-mux/rdmacm-mux.h  |  61 +++
> >>   6 files changed, 868 insertions(+)
> >>   create mode 100644 contrib/rdmacm-mux/Makefile.objs
> >>   create mode 100644 contrib/rdmacm-mux/main.c
> >>   create mode 100644 contrib/rdmacm-mux/rdmacm-mux.h  
> > This commit breaks building with clang on Fedora 28 for me; I get a
> > bunch of
> >  
> 
> Hi Cornelia,
> Thanks for spotting the issue.
> 
> > clang-6.0: error: -libumad: 'linker' input unused [-Werror,-Wunused-command-line-argument]  
> 
> Is really strange, the rdma-mux is part of the contrib directory
> and is not even compiled by default.
> 
> > Explicitly passing --disable-pvrdma to configure disables the offending
> > code.
> >
> > Let me know if you need more information.  
> 
> Can you please send the exact steps you are using to configure and 
> compile QEMU,
> are you compiling on a x86 machine?

Yes, this is on my laptop (up-to-date F28). I can reproduce on current
master, configured with

../configure --target-list="s390x-softmmu s390x-linux-user i386-softmmu x86_64-softmmu cris-softmmu arm-softmmu ppc64-softmmu" --enable-linux-aio --enable-virtfs --enable-trace-backends=simple --cc=clang --enable-rdma --enable-pvrdma

It compiles if I pass --disable-pvrdma instead. It also compiles if I
drop --cc=clang.

I'm building in a build subdirectory; I have already tried purging it
before rebuilding, without luck.

clang --version says

clang version 6.0.1 (tags/RELEASE_601/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

On 1/7/19 7:54 PM, Cornelia Huck wrote:
> On Mon, 7 Jan 2019 19:28:10 +0200
> Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
>
>> On 1/3/19 12:34 PM, Cornelia Huck wrote:
>>> On Sat, 22 Dec 2018 11:50:07 +0200
>>> Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
>>>   
>>>> From: Yuval Shaia <yuval.shaia@oracle.com>
>>>>
>>>> RDMA MAD kernel module (ibcm) disallow more than one MAD-agent for a
>>>> given MAD class.
>>>> This does not go hand-by-hand with qemu pvrdma device's requirements
>>>> where each VM is MAD agent.
>>>> Fix it by adding implementation of RDMA MAD multiplexer service which on
>>>> one hand register as a sole MAD agent with the kernel module and on the
>>>> other hand gives service to more than one VM.
>>>>
>>>> Design Overview:
>>>> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
>>>> ----------------
>>>> A server process is registered to UMAD framework (for this to work the
>>>> rdma_cm kernel module needs to be unloaded) and creates a unix socket to
>>>> listen to incoming request from clients.
>>>> A client process (such as QEMU) connects to this unix socket and
>>>> registers with its own GID.
>>>>
>>>> TX:
>>>> ----
>>>> When client needs to send rdma_cm MAD message it construct it the same
>>>> way as without this multiplexer, i.e. creates a umad packet but this
>>>> time it writes its content to the socket instead of calling umad_send().
>>>> The server, upon receiving such a message fetch local_comm_id from it so
>>>> a context for this session can be maintain and relay the message to UMAD
>>>> layer by calling umad_send().
>>>>
>>>> RX:
>>>> ----
>>>> The server creates a worker thread to process incoming rdma_cm MAD
>>>> messages. When an incoming message arrived (umad_recv()) the server,
>>>> depending on the message type (attr_id) looks for target client by
>>>> either searching in gid->fd table or in local_comm_id->fd table. With
>>>> the extracted fd the server relays to incoming message to the client.
>>>>
>>>> Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
>>>> Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
>>>> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
>>>>
>>>> Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
>>>> ---
>>>>    MAINTAINERS                      |   1 +
>>>>    Makefile                         |   3 +
>>>>    Makefile.objs                    |   1 +
>>>>    contrib/rdmacm-mux/Makefile.objs |   4 +
>>>>    contrib/rdmacm-mux/main.c        | 798 +++++++++++++++++++++++++++++++
>>>>    contrib/rdmacm-mux/rdmacm-mux.h  |  61 +++
>>>>    6 files changed, 868 insertions(+)
>>>>    create mode 100644 contrib/rdmacm-mux/Makefile.objs
>>>>    create mode 100644 contrib/rdmacm-mux/main.c
>>>>    create mode 100644 contrib/rdmacm-mux/rdmacm-mux.h
>>> This commit breaks building with clang on Fedora 28 for me; I get a
>>> bunch of
>>>   
>> Hi Cornelia,
>> Thanks for spotting the issue.
>>
>>> clang-6.0: error: -libumad: 'linker' input unused [-Werror,-Wunused-command-line-argument]
>> Is really strange, the rdma-mux is part of the contrib directory
>> and is not even compiled by default.
>>
>>> Explicitly passing --disable-pvrdma to configure disables the offending
>>> code.
>>>
>>> Let me know if you need more information.
>> Can you please send the exact steps you are using to configure and
>> compile QEMU,
>> are you compiling on a x86 machine?
> Yes, this is on my laptop (up-to-date F28). I can reproduce on current
> master, configured with
>
> ../configure --target-list="s390x-softmmu s390x-linux-user i386-softmmu x86_64-softmmu cris-softmmu arm-softmmu ppc64-softmmu" --enable-linux-aio --enable-virtfs --enable-trace-backends=simple --cc=clang --enable-rdma --enable-pvrdma
>
> It compiles if I pass --disable-pvrdma instead. It also compiles if I
> drop --cc=clang.
>
> I'm building in a build subdirectory; I have already tried purging it
> before rebuilding, without luck.
>
> clang --version says
>
> clang version 6.0.1 (tags/RELEASE_601/final)
> Target: x86_64-unknown-linux-gnu
> Thread model: posix
> InstalledDir: /usr/bin

Thanks for the information, I will look into it.
Marcel

On Tue, 8 Jan 2019 10:41:38 +0200
Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:

> On 1/7/19 7:54 PM, Cornelia Huck wrote:
> > On Mon, 7 Jan 2019 19:28:10 +0200
> > Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
> >  
> >> On 1/3/19 12:34 PM, Cornelia Huck wrote:  

> >>> clang-6.0: error: -libumad: 'linker' input unused [-Werror,-Wunused-command-line-argument]  
> >> Is really strange, the rdma-mux is part of the contrib directory
> >> and is not even compiled by default.
> >>  
> >>> Explicitly passing --disable-pvrdma to configure disables the offending
> >>> code.
> >>>
> >>> Let me know if you need more information.  
> >> Can you please send the exact steps you are using to configure and
> >> compile QEMU,
> >> are you compiling on a x86 machine?  
> > Yes, this is on my laptop (up-to-date F28). I can reproduce on current
> > master, configured with
> >
> > ../configure --target-list="s390x-softmmu s390x-linux-user i386-softmmu x86_64-softmmu cris-softmmu arm-softmmu ppc64-softmmu" --enable-linux-aio --enable-virtfs --enable-trace-backends=simple --cc=clang --enable-rdma --enable-pvrdma
> >
> > It compiles if I pass --disable-pvrdma instead. It also compiles if I
> > drop --cc=clang.
> >
> > I'm building in a build subdirectory; I have already tried purging it
> > before rebuilding, without luck.
> >
> > clang --version says
> >
> > clang version 6.0.1 (tags/RELEASE_601/final)
> > Target: x86_64-unknown-linux-gnu
> > Thread model: posix
> > InstalledDir: /usr/bin  
> 
> Thanks for the information, I will look into it.
> Marcel

Thanks.

Another data point: I see the same on a Fedora 29 on s390x, so this
does not seem to be a broken local setup (unless I managed to mess up
both systems in the same way...) clang --version says

clang version 7.0.0 (Fedora 7.0.0-2.fc29)
Target: s390x-ibm-linux
Thread model: posix
InstalledDir: /usr/bin

On 1/8/19 11:18 AM, Cornelia Huck wrote:
> On Tue, 8 Jan 2019 10:41:38 +0200
> Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
>
>> On 1/7/19 7:54 PM, Cornelia Huck wrote:
>>> On Mon, 7 Jan 2019 19:28:10 +0200
>>> Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
>>>   
>>>> On 1/3/19 12:34 PM, Cornelia Huck wrote:
>>>>> clang-6.0: error: -libumad: 'linker' input unused [-Werror,-Wunused-command-line-argument]
>>>> Is really strange, the rdma-mux is part of the contrib directory
>>>> and is not even compiled by default.
>>>>   
>>>>> Explicitly passing --disable-pvrdma to configure disables the offending
>>>>> code.
>>>>>
>>>>> Let me know if you need more information.
>>>> Can you please send the exact steps you are using to configure and
>>>> compile QEMU,
>>>> are you compiling on a x86 machine?
>>> Yes, this is on my laptop (up-to-date F28). I can reproduce on current
>>> master, configured with
>>>
>>> ../configure --target-list="s390x-softmmu s390x-linux-user i386-softmmu x86_64-softmmu cris-softmmu arm-softmmu ppc64-softmmu" --enable-linux-aio --enable-virtfs --enable-trace-backends=simple --cc=clang --enable-rdma --enable-pvrdma
>>>
>>> It compiles if I pass --disable-pvrdma instead. It also compiles if I
>>> drop --cc=clang.
>>>
>>> I'm building in a build subdirectory; I have already tried purging it
>>> before rebuilding, without luck.
>>>
>>> clang --version says
>>>
>>> clang version 6.0.1 (tags/RELEASE_601/final)
>>> Target: x86_64-unknown-linux-gnu
>>> Thread model: posix
>>> InstalledDir: /usr/bin
>> Thanks for the information, I will look into it.
>> Marcel
> Thanks.
>
> Another data point: I see the same on a Fedora 29 on s390x, so this
> does not seem to be a broken local setup (unless I managed to mess up
> both systems in the same way...) clang --version says
>
> clang version 7.0.0 (Fedora 7.0.0-2.fc29)
> Target: s390x-ibm-linux
> Thread model: posix
> InstalledDir: /usr/bin

Hi Cornelia,
I reproduced the issue and found the root cause:
    contrib/rdmacm-mux/Makefile.objs:
        ifdef CONFIG_PVRDMA
        CFLAGS += -libumad -Wno-format-truncation
        rdmacm-mux-obj-y = main.o
        endif

The above file adds libumad dependency for all project targets even if 
not needed.
Gcc allows that while clang forbids it. (is strange it passed patchew tests)

I will come up with a fix soon.

Thanks,
Marcel