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Szmigiero" Cc: Alex Williamson , Eric Blake , Peter Xu , Fabiano Rosas , Markus Armbruster , =?UTF-8?Q?Daniel_P_=2E_Berrang=C3=A9?= , Avihai Horon , Joao Martins , qemu-devel@nongnu.org References: <4de9762ebf7e7857103eb276d1a26a092aee325d.1739994627.git.maciej.szmigiero@oracle.com> <6ad969cd-e522-4c8b-9d95-05b4df3be002@redhat.com> Content-Language: en-US, fr From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= Autocrypt: addr=clg@redhat.com; keydata= xsFNBFu8o3UBEADP+oJVJaWm5vzZa/iLgpBAuzxSmNYhURZH+guITvSySk30YWfLYGBWQgeo 8NzNXBY3cH7JX3/a0jzmhDc0U61qFxVgrPqs1PQOjp7yRSFuDAnjtRqNvWkvlnRWLFq4+U5t yzYe4SFMjFb6Oc0xkQmaK2flmiJNnnxPttYwKBPd98WfXMmjwAv7QfwW+OL3VlTPADgzkcqj 53bfZ4VblAQrq6Ctbtu7JuUGAxSIL3XqeQlAwwLTfFGrmpY7MroE7n9Rl+hy/kuIrb/TO8n0 ZxYXvvhT7OmRKvbYuc5Jze6o7op/bJHlufY+AquYQ4dPxjPPVUT/DLiUYJ3oVBWFYNbzfOrV RxEwNuRbycttMiZWxgflsQoHF06q/2l4ttS3zsV4TDZudMq0TbCH/uJFPFsbHUN91qwwaN/+ gy1j7o6aWMz+Ib3O9dK2M/j/O/Ube95mdCqN4N/uSnDlca3YDEWrV9jO1mUS/ndOkjxa34ia 70FjwiSQAsyIwqbRO3CGmiOJqDa9qNvd2TJgAaS2WCw/TlBALjVQ7AyoPEoBPj31K74Wc4GS Rm+FSch32ei61yFu6ACdZ12i5Edt+To+hkElzjt6db/UgRUeKfzlMB7PodK7o8NBD8outJGS tsL2GRX24QvvBuusJdMiLGpNz3uqyqwzC5w0Fd34E6G94806fwARAQABzSJDw6lkcmljIExl IEdvYXRlciA8Y2xnQHJlZGhhdC5jb20+wsGRBBMBCAA7FiEEoPZlSPBIlev+awtgUaNDx8/7 7KEFAmTLlVECGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgkQUaNDx8/77KG0eg// S0zIzTcxkrwJ/9XgdcvVTnXLVF9V4/tZPfB7sCp8rpDCEseU6O0TkOVFoGWM39sEMiQBSvyY lHrP7p7E/JYQNNLh441MfaX8RJ5Ul3btluLapm8oHp/vbHKV2IhLcpNCfAqaQKdfk8yazYhh EdxTBlzxPcu+78uE5fF4wusmtutK0JG0sAgq0mHFZX7qKG6LIbdLdaQalZ8CCFMKUhLptW71 xe+aNrn7hScBoOj2kTDRgf9CE7svmjGToJzUxgeh9mIkxAxTu7XU+8lmL28j2L5uNuDOq9vl hM30OT+pfHmyPLtLK8+GXfFDxjea5hZLF+2yolE/ATQFt9AmOmXC+YayrcO2ZvdnKExZS1o8 VUKpZgRnkwMUUReaF/mTauRQGLuS4lDcI4DrARPyLGNbvYlpmJWnGRWCDguQ/LBPpbG7djoy k3NlvoeA757c4DgCzggViqLm0Bae320qEc6z9o0X0ePqSU2f7vcuWN49Uhox5kM5L86DzjEQ RHXndoJkeL8LmHx8DM+kx4aZt0zVfCHwmKTkSTQoAQakLpLte7tWXIio9ZKhUGPv/eHxXEoS 0rOOAZ6np1U/xNR82QbF9qr9TrTVI3GtVe7Vxmff+qoSAxJiZQCo5kt0YlWwti2fFI4xvkOi V7lyhOA3+/3oRKpZYQ86Frlo61HU3r6d9wzOwU0EW7yjdQEQALyDNNMw/08/fsyWEWjfqVhW pOOrX2h+z4q0lOHkjxi/FRIRLfXeZjFfNQNLSoL8j1y2rQOs1j1g+NV3K5hrZYYcMs0xhmrZ KXAHjjDx7FW3sG3jcGjFW5Xk4olTrZwFsZVUcP8XZlArLmkAX3UyrrXEWPSBJCXxDIW1hzwp bV/nVbo/K9XBptT/wPd+RPiOTIIRptjypGY+S23HYBDND3mtfTz/uY0Jytaio9GETj+fFis6 TxFjjbZNUxKpwftu/4RimZ7qL+uM1rG1lLWc9SPtFxRQ8uLvLOUFB1AqHixBcx7LIXSKZEFU CSLB2AE4wXQkJbApye48qnZ09zc929df5gU6hjgqV9Gk1rIfHxvTsYltA1jWalySEScmr0iS YBZjw8Nbd7SxeomAxzBv2l1Fk8fPzR7M616dtb3Z3HLjyvwAwxtfGD7VnvINPbzyibbe9c6g LxYCr23c2Ry0UfFXh6UKD83d5ybqnXrEJ5n/t1+TLGCYGzF2erVYGkQrReJe8Mld3iGVldB7 JhuAU1+d88NS3aBpNF6TbGXqlXGF6Yua6n1cOY2Yb4lO/mDKgjXd3aviqlwVlodC8AwI0Sdu jWryzL5/AGEU2sIDQCHuv1QgzmKwhE58d475KdVX/3Vt5I9kTXpvEpfW18TjlFkdHGESM/Jx IqVsqvhAJkalABEBAAHCwV8EGAECAAkFAlu8o3UCGwwACgkQUaNDx8/77KEhwg//WqVopd5k 8hQb9VVdk6RQOCTfo6wHhEqgjbXQGlaxKHoXywEQBi8eULbeMQf5l4+tHJWBxswQ93IHBQjK yKyNr4FXseUI5O20XVNYDJZUrhA4yn0e/Af0IX25d94HXQ5sMTWr1qlSK6Zu79lbH3R57w9j hQm9emQEp785ui3A5U2Lqp6nWYWXz0eUZ0Tad2zC71Gg9VazU9MXyWn749s0nXbVLcLS0yop s302Gf3ZmtgfXTX/W+M25hiVRRKCH88yr6it+OMJBUndQVAA/fE9hYom6t/zqA248j0QAV/p LHH3hSirE1mv+7jpQnhMvatrwUpeXrOiEw1nHzWCqOJUZ4SY+HmGFW0YirWV2mYKoaGO2YBU wYF7O9TI3GEEgRMBIRT98fHa0NPwtlTktVISl73LpgVscdW8yg9Gc82oe8FzU1uHjU8b10lU XOMHpqDDEV9//r4ZhkKZ9C4O+YZcTFu+mvAY3GlqivBNkmYsHYSlFsbxc37E1HpTEaSWsGfA HQoPn9qrDJgsgcbBVc1gkUT6hnxShKPp4PlsZVMNjvPAnr5TEBgHkk54HQRhhwcYv1T2QumQ izDiU6iOrUzBThaMhZO3i927SG2DwWDVzZltKrCMD1aMPvb3NU8FOYRhNmIFR3fcalYr+9gD uVKe8BVz4atMOoktmt0GWTOC8P4= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.438, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 2/26/25 22:04, Maciej S. Szmigiero wrote: > On 26.02.2025 11:43, Cédric Le Goater wrote: >> On 2/19/25 21:34, Maciej S. Szmigiero wrote: >>> From: "Maciej S. Szmigiero" >>> >>> The multifd received data needs to be reassembled since device state >>> packets sent via different multifd channels can arrive out-of-order. >>> >>> Therefore, each VFIO device state packet carries a header indicating its >>> position in the stream. >>> The raw device state data is saved into a VFIOStateBuffer for later >>> in-order loading into the device. >>> >>> The last such VFIO device state packet should have >>> VFIO_DEVICE_STATE_CONFIG_STATE flag set and carry the device config state. >>> >>> Signed-off-by: Maciej S. Szmigiero >>> --- >>>   hw/vfio/migration-multifd.c | 103 ++++++++++++++++++++++++++++++++++++ >>>   hw/vfio/migration-multifd.h |   3 ++ >>>   hw/vfio/migration.c         |   1 + >>>   hw/vfio/trace-events        |   1 + >>>   4 files changed, 108 insertions(+) >>> >>> diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c >>> index c2defc0efef0..5d5ee1393674 100644 >>> --- a/hw/vfio/migration-multifd.c >>> +++ b/hw/vfio/migration-multifd.c >>> @@ -42,6 +42,11 @@ typedef struct VFIOStateBuffer { >>>   } VFIOStateBuffer; >>>   typedef struct VFIOMultifd { >>> +    VFIOStateBuffers load_bufs; >>> +    QemuCond load_bufs_buffer_ready_cond; >>> +    QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ >>> +    uint32_t load_buf_idx; >>> +    uint32_t load_buf_idx_last; >>>   } VFIOMultifd; >>>   static void vfio_state_buffer_clear(gpointer data) >>> @@ -87,15 +92,113 @@ static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, guint idx) >>>       return &g_array_index(bufs->array, VFIOStateBuffer, idx); >>>   } >> >> this routine expects load_bufs_mutex to be locked ? May be say so. > > I guess the comment above pertains to the vfio_load_state_buffer_insert() > below. > > Do you mean it should have a comment that it expects to be called > under load_bufs_mutex? Just a one liner like : /* called with load_bufs_mutex locked */ ? It's good to have for the future generations. > >>> +static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, >> >> could you pass VFIOMultifd* instead  ? > > No, it needs vbasedev->migration_max_queued_buffers too (introduced > in later patch). > > Also, most of VFIO routines (besides very small helpers/wrappers) > take VFIODevice *. OK. It's minor but I prefer when parameters are limited to the minimum. Having 'VFIODevice *' opens doors to a lot of state. Thanks, C. > >>> +                                          VFIODeviceStatePacket *packet, >>> +                                          size_t packet_total_size, >>> +                                          Error **errp) >>> +{ >>> +    VFIOMigration *migration = vbasedev->migration; >>> +    VFIOMultifd *multifd = migration->multifd; >>> +    VFIOStateBuffer *lb; >>> + >>> +    vfio_state_buffers_assert_init(&multifd->load_bufs); >>> +    if (packet->idx >= vfio_state_buffers_size_get(&multifd->load_bufs)) { >>> +        vfio_state_buffers_size_set(&multifd->load_bufs, packet->idx + 1); >>> +    } >>> + >>> +    lb = vfio_state_buffers_at(&multifd->load_bufs, packet->idx); >>> +    if (lb->is_present) { >>> +        error_setg(errp, "state buffer %" PRIu32 " already filled", >>> +                   packet->idx); >>> +        return false; >>> +    } >>> + >>> +    assert(packet->idx >= multifd->load_buf_idx); >>> + >>> +    lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet)); >>> +    lb->len = packet_total_size - sizeof(*packet); >>> +    lb->is_present = true; >>> + >>> +    return true; >>> +} >>> + >>> +bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, >>> +                            Error **errp) >> >> >> AFAICS, the only users of the .load_state_buffer() handlers is >> multifd_device_state_recv(). >> >> Please rename to vfio_multifd_load_state_buffer(). > > Renamed it accordingly. > >>> +{ >>> +    VFIODevice *vbasedev = opaque; >>> +    VFIOMigration *migration = vbasedev->migration; >>> +    VFIOMultifd *multifd = migration->multifd; >>> +    VFIODeviceStatePacket *packet = (VFIODeviceStatePacket *)data; >>> + >>> +    /* >>> +     * Holding BQL here would violate the lock order and can cause >>> +     * a deadlock once we attempt to lock load_bufs_mutex below. >>> +     */ >>> +    assert(!bql_locked()); >>> + >>> +    if (!vfio_multifd_transfer_enabled(vbasedev)) { >>> +        error_setg(errp, >>> +                   "got device state packet but not doing multifd transfer"); >>> +        return false; >>> +    } >>> + >>> +    assert(multifd); >>> + >>> +    if (data_size < sizeof(*packet)) { >>> +        error_setg(errp, "packet too short at %zu (min is %zu)", >>> +                   data_size, sizeof(*packet)); >>> +        return false; >>> +    } >>> + >>> +    if (packet->version != VFIO_DEVICE_STATE_PACKET_VER_CURRENT) { >>> +        error_setg(errp, "packet has unknown version %" PRIu32, >>> +                   packet->version); >>> +        return false; >>> +    } >>> + >>> +    if (packet->idx == UINT32_MAX) { >>> +        error_setg(errp, "packet has too high idx"); >> >> or "packet index is invalid" ? > > Changed the error message. > >>> +        return false; >>> +    } >>> + >>> +    trace_vfio_load_state_device_buffer_incoming(vbasedev->name, packet->idx); >>> + >>> +    QEMU_LOCK_GUARD(&multifd->load_bufs_mutex); >> >> Using WITH_QEMU_LOCK_GUARD() would be cleaner I think. > > Changed into a WITH_QEMU_LOCK_GUARD() block. > >> >> >> Thanks, >> >> C. > > Thanks, > Maciej >