On Tue, Apr 11, 2023 at 07:17:14AM +0000, Angus Chen wrote: > > > > -----Original Message----- > > From: Michael S. Tsirkin <[email protected]> > > Sent: Tuesday, April 11, 2023 2:56 PM > > To: Angus Chen <[email protected]> > > Cc: Jason Wang <[email protected]>; > > [email protected]; [email protected] > > Subject: Re: [PATCH] virtio_pci: Wait for legacy device to be reset > > > > On Tue, Apr 11, 2023 at 06:49:03AM +0000, Angus Chen wrote: > > > > > > > > > > -----Original Message----- > > > > From: Michael S. Tsirkin <[email protected]> > > > > Sent: Tuesday, April 11, 2023 2:47 PM > > > > To: Angus Chen <[email protected]> > > > > Cc: Jason Wang <[email protected]>; > > > > [email protected]; [email protected] > > > > Subject: Re: [PATCH] virtio_pci: Wait for legacy device to be reset > > > > > > > > On Tue, Apr 11, 2023 at 06:36:39AM +0000, Angus Chen wrote: > > > > > Hi. > > > > > > > > > > > -----Original Message----- > > > > > > From: Jason Wang <[email protected]> > > > > > > Sent: Tuesday, April 11, 2023 1:24 PM > > > > > > To: Angus Chen <[email protected]> > > > > > > Cc: [email protected]; [email protected]; > > > > > > [email protected] > > > > > > Subject: Re: [PATCH] virtio_pci: Wait for legacy device to be reset > > > > > > > > > > > > On Tue, Apr 11, 2023 at 9:39 AM Angus Chen > > > > <[email protected]> > > > > > > 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. > > > > > > > > > > > > The only concern is if it's too late to do this. > > > > > > > > > > > > Btw, any reason you want to have a legacy hardware implementation. > > > > > > It > > > > > > will be very tricky to work correctly. > > > > > En,I found this in the real production environment some times about > > one > > > > year ago. > > > > > and I fix this out of tree.our virtio card had been sold about > > > > > thousands . > > > > > > > > > > Now,we created a new card, it support virtio 0.95,1.0,1.1 etc. > > > > > > > > I am not 100% sure what does this mean. > > > > So it's a transitional device then? > > > Hi mst,it is a real card in the In cloud computing ,not transitional > > > device. > > > > yes, a real card. But you said it supports 0.95, 1.0 and 1.1 guests, > > so this is what the virtio spec calls a transitional device, right? > > > > To simplify transition from these earlier draft interfaces, > > a device MAY implement: > > > > \begin{description} > > \item[Transitional Device] > > a device supporting both drivers conforming to this > > specification, and allowing legacy drivers. > > \end{description} > > > > or did I misunderstand? > > > Yes, I'm not sure whether I make myself clear. > We support the vritio spec 0.95, 1.0 and 1.1 in the same card. > And the numer of devices is 1k per one card. > > Btw, thanks a lot for the work of redhat, we just Implement the virtio > protocol by hardware.
Yes, not very clear still. What are the device and vendor ID of the card? Does it have the virtio capabilities? Thanks > > > > > > > > > > > > > > > And we use this host vdpa+ legacy virtio in vm to hot migration,we > > found > > > > that the > > > > > Legacy model often get the middle state value after reset and probe > > again. > > > > > The Soc is Simulated by fpga which is run slower than the host,so > > > > > the > > same > > > > bug > > > > > Is found more frequently when the host use the other kernel like > > ubuntu or > > > > centos8. > > > > > > > > > > So we hope we can fix this by upstream . > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > > > > Signed-off-by: Angus Chen <[email protected]> > > > > > > > --- > > > > > > > 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 <[email protected]> > > > > > > > */ > > > > > > > > > > > > > > +#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 > > > > > > > > > > > > > > > > _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
