Michael S. Tsirkin
2023-Apr-11 06:29 UTC
[PATCH] virtio_pci: Wait for legacy device to be reset
On Tue, Apr 11, 2023 at 09:38:32AM +0800, Angus Chen wrote:> We read the status of device after reset, > It is not guaranteed that the device be reseted successfully.Sorry not guaranteed by what? I am guessing you have a legacy device that does not reset fully on write, and you need to wait?> 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 at jaguarmicro.com>Generally I don't much like touching legacy, no telling what that will do. Case in point, is your device a pure legacy device or a transitional device?> --- > 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 at 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);The problem with this is that it will break surprise removal even worse than it's already broken.> /* Flush pending VQ/configuration callbacks. */ > vp_synchronize_vectors(vdev); > } > -- > 2.25.1