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Message-ID: <1681180912.9817035-2-xuanzhuo@linux.alibaba.com>
Subject: Re: [PATCH] virtio_pci: Wait for legacy device to be reset
Date:   Tue, 11 Apr 2023 10:41:52 +0800
From:   Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To:     Angus Chen <angus.chen@jaguarmicro.com>
Cc:     virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org,
        Angus Chen <angus.chen@jaguarmicro.com>, mst@redhat.com,
        jasowang@redhat.com
References: <20230411013833.1305-1-angus.chen@jaguarmicro.com>
In-Reply-To: <20230411013833.1305-1-angus.chen@jaguarmicro.com>
Precedence: bulk

On Tue, 11 Apr 2023 09:38:32 +0800, Angus Chen <angus.chen@jaguarmicro.com> wrote:
> We read the status of device after reset,
> It is not guaranteed that the device be reseted successfully.
> We can use a while loop to make sure that,like the modern device did.
> The spec is not request it ,but it work.
>
> Signed-off-by: Angus Chen <angus.chen@jaguarmicro.com>

LGTM

Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>


> ---
>  drivers/virtio/virtio_pci_legacy.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> index 2257f1b3d8ae..f2d241563e4f 100644
> --- a/drivers/virtio/virtio_pci_legacy.c
> +++ b/drivers/virtio/virtio_pci_legacy.c
> @@ -14,6 +14,7 @@
>   *  Michael S. Tsirkin <mst@redhat.com>
>   */
>
> +#include <linux/delay.h>
>  #include "linux/virtio_pci_legacy.h"
>  #include "virtio_pci_common.h"
>
> @@ -97,7 +98,8 @@ static void vp_reset(struct virtio_device *vdev)
>  	vp_legacy_set_status(&vp_dev->ldev, 0);
>  	/* Flush out the status write, and flush in device writes,
>  	 * including MSi-X interrupts, if any. */
> -	vp_legacy_get_status(&vp_dev->ldev);
> +	while (vp_legacy_get_status(&vp_dev->ldev))
> +		msleep(1);
>  	/* Flush pending VQ/configuration callbacks. */
>  	vp_synchronize_vectors(vdev);
>  }
> --
> 2.25.1
>