Re: [PATCH RESEND 3/4] migration/rdma: destination: create the return patch after the first accept

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* lizhijian@fujitsu.com (lizhijian@fujitsu.com) wrote:
> should make some changes for this patch like below:

Can you resend a version with this flattned into it please.

Dave

> # git diff
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 3b228c46ebf..067ea272276 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -316,7 +316,7 @@ typedef struct RDMALocalBlocks {
>   typedef struct RDMAContext {
>       char *host;
>       int port;
> -    const char *host_port;
> +    char *host_port;
> 
>       RDMAWorkRequestData wr_data[RDMA_WRID_MAX];
> 
> @@ -2393,7 +2393,9 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
>           rdma->channel = NULL;
>       }
>       g_free(rdma->host);
> +    g_free(rdma->host_port);
>       rdma->host = NULL;
> +    rdma->host_port = NULL;
>   }
> 
> 
> @@ -2649,7 +2651,7 @@ static void *qemu_rdma_data_init(const char *host_port, Error **errp)
>           if (!inet_parse(addr, host_port, NULL)) {
>               rdma->port = atoi(addr->port);
>               rdma->host = g_strdup(addr->host);
> -            rdma->host_port = host_port;
> +            rdma->host_port = g_strdup(host_port);
>           } else {
>               ERROR(errp, "bad RDMA migration address '%s'", host_port);
>               g_free(rdma);
> @@ -4076,6 +4078,7 @@ err:
>       error_propagate(errp, local_err);
>       if (rdma) {
>           g_free(rdma->host);
> +        g_free(rdma->host_port);
>       }
>       g_free(rdma);
>       g_free(rdma_return_path);
> 
> 
> On 20/05/2021 16.11, Li Zhijian wrote:
> > destination side:
> > $ build/qemu-system-x86_64 -enable-kvm -netdev tap,id=hn0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown -device e1000,netdev=hn0,mac=50:52:54:00:11:22 -boot c -drive if=none,file=./Fedora-rdma-server-migration.qcow2,id=drive-virtio-disk0 -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0 -m 2048 -smp 2 -device piix3-usb-uhci -device usb-tablet -monitor stdio -vga qxl -spice streaming-video=filter,port=5902,disable-ticketing -incoming rdma:192.168.1.10:8888
> > (qemu) migrate_set_capability postcopy-ram on
> > (qemu)
> > dest_init RDMA Device opened: kernel name rocep1s0f0 uverbs device name uverbs0, infiniband_verbs class device path /sys/class/infiniband_verbs/uverbs0, infiniband class device path /sys/class/infiniband/rocep1s0f0, transport: (2) Ethernet
> > Segmentation fault (core dumped)
> >
> >   (gdb) bt
> >   #0  qemu_rdma_accept (rdma=0x0) at ../migration/rdma.c:3272
> >   #1  rdma_accept_incoming_migration (opaque=0x0) at     ../migration/rdma.c:3986
> >   #2  0x0000563c9e51f02a in aio_dispatch_handler
> >       (ctx=ctx@entry=0x563ca0606010, node=0x563ca12b2150) at ../util/aio-posix.c:329
> >   #3  0x0000563c9e51f752 in aio_dispatch_handlers (ctx=0x563ca0606010) at      ../util/aio-posix.c:372
> >   #4  aio_dispatch (ctx=0x563ca0606010) at ../util/aio-posix.c:382
> >   #5  0x0000563c9e4f4d9e in aio_ctx_dispatch (source=<optimized out>,      callback=<optimized out>, user_data=<optimized out>)    at ../util/async.c:306
> >   #6  0x00007fe96ef3fa9f in g_main_context_dispatch () at      /lib64/libglib-2.0.so.0
> >   #7  0x0000563c9e4ffeb8 in glib_pollfds_poll () at     ../util/main-loop.c:231
> >   #8  os_host_main_loop_wait (timeout=12188789) at     ../util/main-loop.c:254
> >   #9  main_loop_wait (nonblocking=nonblocking@entry=0) at     ../util/main-loop.c:530
> >   #10 0x0000563c9e3c7211 in qemu_main_loop () at     ../softmmu/runstate.c:725
> >   #11 0x0000563c9dfd46fe in main (argc=<optimized out>, argv=<optimized     out>, envp=<optimized out>) at ../softmmu/main.c:50
> >
> > The rdma return path will not be created when qemu incoming is starting
> > since migrate_copy() is false at that moment, then a  NULL return path
> > rdma was referenced if the user enabled postcopy later.
> >
> > Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> > ---
> >   migration/rdma.c | 29 ++++++++++++++++++-----------
> >   1 file changed, 18 insertions(+), 11 deletions(-)
> >
> > diff --git a/migration/rdma.c b/migration/rdma.c
> > index 651534e825..3b228c46eb 100644
> > --- a/migration/rdma.c
> > +++ b/migration/rdma.c
> > @@ -316,6 +316,7 @@ typedef struct RDMALocalBlocks {
> >   typedef struct RDMAContext {
> >       char *host;
> >       int port;
> > +    const char *host_port;
> >   
> >       RDMAWorkRequestData wr_data[RDMA_WRID_MAX];
> >   
> > @@ -2648,6 +2649,7 @@ static void *qemu_rdma_data_init(const char *host_port, Error **errp)
> >           if (!inet_parse(addr, host_port, NULL)) {
> >               rdma->port = atoi(addr->port);
> >               rdma->host = g_strdup(addr->host);
> > +            rdma->host_port = host_port;
> >           } else {
> >               ERROR(errp, "bad RDMA migration address '%s'", host_port);
> >               g_free(rdma);
> > @@ -3276,6 +3278,7 @@ static int qemu_rdma_accept(RDMAContext *rdma)
> >                                               .private_data = &cap,
> >                                               .private_data_len = sizeof(cap),
> >                                            };
> > +    RDMAContext *rdma_return_path = NULL;
> >       struct rdma_cm_event *cm_event;
> >       struct ibv_context *verbs;
> >       int ret = -EINVAL;
> > @@ -3291,6 +3294,20 @@ static int qemu_rdma_accept(RDMAContext *rdma)
> >           goto err_rdma_dest_wait;
> >       }
> >   
> > +    /*
> > +     * initialize the RDMAContext for return path for postcopy after first
> > +     * connection is accepted.
> > +     */
> > +    if (migrate_postcopy() && !rdma->is_return_path) {
> > +        rdma_return_path = qemu_rdma_data_init(rdma->host_port, NULL);
> > +        if (rdma_return_path == NULL) {
> > +            rdma_ack_cm_event(cm_event);
> > +            goto err_rdma_dest_wait;
> > +        }
> > +
> > +        qemu_rdma_return_path_dest_init(rdma_return_path, rdma);
> > +    }
> > +
> >       memcpy(&cap, cm_event->param.conn.private_data, sizeof(cap));
> >   
> >       network_to_caps(&cap);
> > @@ -3406,6 +3423,7 @@ static int qemu_rdma_accept(RDMAContext *rdma)
> >   err_rdma_dest_wait:
> >       rdma->error_state = ret;
> >       qemu_rdma_cleanup(rdma);
> > +    g_free(rdma_return_path);
> >       return ret;
> >   }
> >   
> > @@ -4048,17 +4066,6 @@ void rdma_start_incoming_migration(const char *host_port, Error **errp)
> >   
> >       trace_rdma_start_incoming_migration_after_rdma_listen();
> >   
> > -    /* initialize the RDMAContext for return path */
> > -    if (migrate_postcopy()) {
> > -        rdma_return_path = qemu_rdma_data_init(host_port, &local_err);
> > -
> > -        if (rdma_return_path == NULL) {
> > -            goto cleanup_rdma;
> > -        }
> > -
> > -        qemu_rdma_return_path_dest_init(rdma_return_path, rdma);
> > -    }
> > -
> >       qemu_set_fd_handler(rdma->channel->fd, rdma_accept_incoming_migration,
> >                           NULL, (void *)(intptr_t)rdma);
> >       return;
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK