From: Yishai Hadas <yishaih@nvidia.com>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: <kvm@vger.kernel.org>
Subject: Re: [bug report] vfio/mlx5: Let firmware knows upon leaving PRE_COPY back to RUNNING
Date: Thu, 9 May 2024 17:04:43 +0300 [thread overview]
Message-ID: <cff7ba09-2437-45f5-93ee-e5d941e550f7@nvidia.com> (raw)
In-Reply-To: <3412835f-4927-4c9a-830d-4029fa0dc7e0@moroto.mountain>
On 09/05/2024 16:36, Dan Carpenter wrote:
> Hello Yishai Hadas,
>
> Commit 6de042240b0f ("vfio/mlx5: Let firmware knows upon leaving
> PRE_COPY back to RUNNING") from Feb 5, 2024 (linux-next), leads to
> the following Smatch static checker warning:
>
> drivers/vfio/pci/mlx5/main.c:1164 mlx5vf_pci_step_device_state_locked()
> error: uninitialized symbol 'state'.
>
> drivers/vfio/pci/mlx5/main.c
> 1142 if ((cur == VFIO_DEVICE_STATE_PRE_COPY && new == VFIO_DEVICE_STATE_RUNNING) ||
> 1143 (cur == VFIO_DEVICE_STATE_PRE_COPY_P2P &&
> 1144 new == VFIO_DEVICE_STATE_RUNNING_P2P)) {
> 1145 struct mlx5_vf_migration_file *migf = mvdev->saving_migf;
> 1146 struct mlx5_vhca_data_buffer *buf;
> 1147 enum mlx5_vf_migf_state state;
> ^^^^^
> 1148 size_t size;
> 1149
> 1150 ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &size, NULL,
> 1151 MLX5VF_QUERY_INC | MLX5VF_QUERY_CLEANUP);
> 1152 if (ret)
> 1153 return ERR_PTR(ret);
> 1154 buf = mlx5vf_get_data_buffer(migf, size, DMA_FROM_DEVICE);
> 1155 if (IS_ERR(buf))
> 1156 return ERR_CAST(buf);
> 1157 /* pre_copy cleanup */
> 1158 ret = mlx5vf_cmd_save_vhca_state(mvdev, migf, buf, false, false);
> 1159 if (ret) {
> 1160 mlx5vf_put_data_buffer(buf);
> 1161 return ERR_PTR(ret);
> 1162 }
> 1163 mlx5vf_disable_fds(mvdev, &state);
> ^^^^^^
> state is only set some of the time.
The 'state' will *always* be set in the above flow.
As we are in the source side of the migration we have a valid
saving_migf (see line 1145 above), as we pass in a non NULL pointer for
the state, it will be always filled inside.
We not just make mlx5vf_disable_fds()
> return an error code?
mlx5vf_disable_fd() is a cleanup function that can't fail.
It just holds/sets the state of the migf following the completion of the
asynchronous SAVE command that was issued in line 1158.
So, it's a false alarm.
Thanks,
Yishai
>
> --> 1164 return (state != MLX5_MIGF_STATE_ERROR) ? NULL : ERR_PTR(-EIO);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Uninitialized.
>
> 1165 }
>
> regards,
> dan carpenter
next prev parent reply other threads:[~2024-05-09 14:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 13:36 [bug report] vfio/mlx5: Let firmware knows upon leaving PRE_COPY back to RUNNING Dan Carpenter
2024-05-09 14:04 ` Yishai Hadas [this message]
2024-05-09 14:43 ` Dan Carpenter
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