RE: [PATCH] virtio_pci: Wait for legacy device to be reset

[Angus Chen]

> -----Original Message-----
> From: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> Sent: Tuesday, April 11, 2023 10:42 AM
> To: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>
> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> Angus Chen <angus.chen@xxxxxxxxxxxxxxx>; mst@xxxxxxxxxx;
> jasowang@xxxxxxxxxx
> Subject: Re: [PATCH] virtio_pci: Wait for legacy device to be reset
> 
> On Tue, 11 Apr 2023 09:38:32 +0800, Angus Chen
> <angus.chen@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx>
> 
> LGTM

Thank you for you reply.
> 
> Reviewed-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> 
> 
> > ---
> >  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@xxxxxxxxxx>
> >   */
> >
> > +#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
> >