Re: [Qemu-devel] [RFC PATCH RDMA support v3: 05/10] RDMA connection establishment (migration-rdma.c).

[Paolo Bonzini]

Il 11/03/2013 05:33, address@hidden ha scritto:
> From: "Michael R. Hines" <address@hidden>
> 
> Use 'migrate rdma:host:port' to begin the migration.
> 
> The TCP control channel has finally been eliminated
> when RDMA is used. Documentation of the use of SEND message
> for transferring device state is covered in docs/rdma.txt
> 
> Signed-off-by: Michael R. Hines <address@hidden>
> ---
>  migration-rdma.c |  198 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 198 insertions(+)
>  create mode 100644 migration-rdma.c
> 
> diff --git a/migration-rdma.c b/migration-rdma.c
> new file mode 100644
> index 0000000..822b17a
> --- /dev/null
> +++ b/migration-rdma.c
> @@ -0,0 +1,198 @@
> +/*
> + *  Copyright (C) 2013 Michael R. Hines <address@hidden>
> + *  Copyright (C) 2013 Jiuxing Liu <address@hidden>
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; under version 2 of the License.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +#include "migration/rdma.h"
> +#include "qemu-common.h"
> +#include "migration/migration.h"
> +#include "migration/qemu-file.h"
> +#include <stdio.h>
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +#include <netdb.h>
> +#include <arpa/inet.h>
> +#include <string.h>
> +
> +//#define DEBUG_MIGRATION_RDMA
> +
> +#ifdef DEBUG_MIGRATION_RDMA
> +#define DPRINTF(fmt, ...) \
> +    do { printf("migration-rdma: " fmt, ## __VA_ARGS__); } while (0)
> +#else
> +#define DPRINTF(fmt, ...) \
> +    do { } while (0)
> +#endif
> +
> +static int rdma_accept_incoming_migration(RDMAData *rdma, Error **errp)
> +{
> +    int ret;
> +
> +    ret = qemu_rdma_migrate_listen(rdma, rdma->host, rdma->port);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error listening!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_alloc_qp(&rdma->rdma_ctx);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error allocating qp!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_migrate_accept(&rdma->rdma_ctx, NULL, NULL, NULL, 0);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error accepting connection!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_post_recv_qemu_file(rdma);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error posting second qemu file 
> recv!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_post_send_remote_info(rdma);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error sending remote info!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_wait_for_wrid(rdma, RDMA_WRID_SEND_REMOTE_INFO);
> +    if (ret < 0) {
> +        qemu_rdma_print("rdma migration: polling remote info error!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    rdma->total_bytes = 0;
> +    rdma->enabled = 1;
> +    qemu_rdma_dump_gid("server_connect", rdma->rdma_ctx.cm_id);
> +    return 0;
> +
> +err_rdma_server_wait:
> +    qemu_rdma_cleanup(rdma);
> +    return -1;
> +
> +}
> +
> +int rdma_start_incoming_migration(const char * host_port, Error **errp)
> +{
> +    QEMUFile *f;
> +    int ret;
> +    RDMAData rdma;
> +
> +    if ((ret = qemu_rdma_data_init(&rdma, host_port, errp)) < 0)
> +        return ret; 
> +
> +    ret = qemu_rdma_server_init(&rdma, NULL);
> +
> +    DPRINTF("Starting RDMA-based incoming migration\n");
> +
> +    if (!ret) {
> +        DPRINTF("qemu_rdma_server_init success\n");
> +        ret = qemu_rdma_server_prepare(&rdma, NULL);
> +
> +        if (!ret) {
> +            DPRINTF("qemu_rdma_server_prepare success\n");
> +
> +            ret = rdma_accept_incoming_migration(&rdma, NULL);
> +            if(!ret)
> +                DPRINTF("qemu_rdma_accept_incoming_migration success\n");
> +            f = qemu_fopen_rdma(&rdma);
> +            if (f == NULL) {
> +                fprintf(stderr, "could not qemu_fopen RDMA\n");
> +                ret = -EIO;
> +            }
> +
> +            process_incoming_migration(f);
> +        }
> +    }
> +
> +    return ret;
> +}
> +
> +/*
> + * Not sure what this is for yet...
> + */
> +static int qemu_rdma_errno(MigrationState *s)
> +{
> +    return 0;
> +}
> +
> +/*
> + * SEND messages for device state only.
> + * pc.ram is handled elsewhere...
> + */
> +static int qemu_rdma_send(MigrationState *s, const void * buf, size_t size)
> +{
> +    size_t len, remaining = size;
> +    uint8_t * data = (void *) buf;
> +
> +    if (qemu_rdma_write_flush(&s->rdma) < 0) {
> +        qemu_file_set_error(s->file, -EIO);
> +        return -EIO;
> +    }
> +
> +    while(remaining) {
> +        len = MIN(remaining, RDMA_SEND_INCREMENT);
> +        remaining -= len;
> +        DPRINTF("iter Sending %" PRId64 "-byte SEND\n", len); 
> +
> +        if(qemu_rdma_exchange_send(&s->rdma, data, len) < 0)
> +                return -EINVAL;
> +
> +        data += len;
> +    }
> +
> +    return size;
> +}
> +
> +static int qemu_rdma_close(MigrationState *s)
> +{
> +    DPRINTF("qemu_rdma_close\n");
> +    qemu_rdma_cleanup(&s->rdma);
> +    return 0;
> +}
> +
> +void rdma_start_outgoing_migration(MigrationState *s, const char *host_port, 
> Error **errp)
> +{
> +    int ret;
> +
> +#ifndef CONFIG_RDMA
> +    error_set(errp, QERR_FEATURE_DISABLED, "rdma migration");
> +    return;
> +#endif
> +
> +    if (qemu_rdma_data_init(&s->rdma, host_port, errp) < 0)
> +        return; 
> +
> +    ret = qemu_rdma_client_init(&s->rdma, NULL);
> +    if(!ret) {
> +        DPRINTF("qemu_rdma_client_init success\n");
> +        ret = qemu_rdma_client_connect(&s->rdma, NULL);
> +
> +        if(!ret) {
> +            s->get_error = qemu_rdma_errno;
> +            s->write = qemu_rdma_send;
> +            s->close = qemu_rdma_close;
> +            s->fd = -2;
> +            DPRINTF("qemu_rdma_client_connect success\n");
> +            migrate_fd_connect(s);
> +            return;
> +        }
> +    }
> +
> +    s->fd = -1;
> +    migrate_fd_error(s);
> +}
> 

Note that as soon as the pending migration patches hit upstream, almost
all of this code will move to QEMUFileRDMA (in particular qemu_rdma_send
and qemu_rdma_close).  It should become simpler.

Paolo