Re: [PATCH v4 18/19] vdpa: Add device migration blocker

[Jason Wang <jasowang@redhat.com>]

在 2022/7/18 18:29, Eugenio Pérez 写道:
> Since the vhost-vdpa device is exposing _F_LOG, adding a migration blocker if
> it uses CVQ.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>   include/hw/virtio/vhost-vdpa.h |  1 +
>   hw/virtio/vhost-vdpa.c         | 14 ++++++++++++++
>   2 files changed, 15 insertions(+)
>
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index 1111d85643..d10a89303e 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -35,6 +35,7 @@ typedef struct vhost_vdpa {
>       bool shadow_vqs_enabled;
>       /* IOVA mapping used by the Shadow Virtqueue */
>       VhostIOVATree *iova_tree;
> +    Error *migration_blocker;
>       GPtrArray *shadow_vqs;
>       const VhostShadowVirtqueueOps *shadow_vq_ops;
>       void *shadow_vq_ops_opaque;
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index beaaa7049a..795ed5a049 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -20,6 +20,7 @@
>   #include "hw/virtio/vhost-shadow-virtqueue.h"
>   #include "hw/virtio/vhost-vdpa.h"
>   #include "exec/address-spaces.h"
> +#include "migration/blocker.h"
>   #include "qemu/cutils.h"
>   #include "qemu/main-loop.h"
>   #include "cpu.h"
> @@ -1022,6 +1023,13 @@ static bool vhost_vdpa_svqs_start(struct vhost_dev *dev)
>           return true;
>       }
>   
> +    if (v->migration_blocker) {
> +        int r = migrate_add_blocker(v->migration_blocker, &err);
> +        if (unlikely(r < 0)) {
> +            goto err_migration_blocker;
> +        }
> +    }
> +
>       for (i = 0; i < v->shadow_vqs->len; ++i) {
>           VirtQueue *vq = virtio_get_queue(dev->vdev, dev->vq_index + i);
>           VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
> @@ -1064,6 +1072,9 @@ err:
>           vhost_svq_stop(svq);
>       }
>   
> +err_migration_blocker:
> +    error_reportf_err(err, "Cannot setup SVQ %u: ", i);


So I got this:

FAILED: libqemu-x86_64-softmmu.fa.p/hw_virtio_vhost-vdpa.c.o
cc -m64 -mcx16 -Ilibqemu-x86_64-softmmu.fa.p -I. -I.. -Itarget/i386 
-I../target/i386 -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/pixman-1 
-I/usr/include/capstone -I/usr/include/glib-2.0 
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include -fdiagnostics-color=auto 
-Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -isystem 
/home/devel/git/qemu/linux-headers -isystem linux-headers -iquote . 
-iquote /home/devel/git/qemu -iquote /home/devel/git/qemu/include 
-iquote /home/devel/git/qemu/tcg/i386 -pthread -U_FORTIFY_SOURCE 
-D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 
-D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef 
-Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common 
-fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits 
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers 
-Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined 
-Wimplicit-fallthrough=2 -Wno-missing-include-dirs 
-Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -fPIE 
-isystem../linux-headers -isystemlinux-headers -DNEED_CPU_H 
'-DCONFIG_TARGET="x86_64-softmmu-config-target.h"' 
'-DCONFIG_DEVICES="x86_64-softmmu-config-devices.h"' -MD -MQ 
libqemu-x86_64-softmmu.fa.p/hw_virtio_vhost-vdpa.c.o -MF 
libqemu-x86_64-softmmu.fa.p/hw_virtio_vhost-vdpa.c.o.d -o 
libqemu-x86_64-softmmu.fa.p/hw_virtio_vhost-vdpa.c.o -c 
../hw/virtio/vhost-vdpa.c
../hw/virtio/vhost-vdpa.c: In function ‘vhost_vdpa_dev_start’:
../hw/virtio/vhost-vdpa.c:1076:5: error: ‘i’ may be used uninitialized 
in this function [-Werror=maybe-uninitialized]
  1076 |     error_reportf_err(err, "Cannot setup SVQ %u: ", i);
       |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../hw/virtio/vhost-vdpa.c:1020:14: note: ‘i’ was declared here
  1020 |     unsigned i;
       |              ^
cc1: all warnings being treated as errors

And this error is kind of duplicated with the one that is reported in 
label "err" above.

Thanks


> +
>       return false;
>   }
>   
> @@ -1083,6 +1094,9 @@ static bool vhost_vdpa_svqs_stop(struct vhost_dev *dev)
>           }
>       }
>   
> +    if (v->migration_blocker) {
> +        migrate_del_blocker(v->migration_blocker);
> +    }
>       return true;
>   }
>