On Thu, Dec 09, 2021 at 11:21:36AM +0800, 王贇 wrote:
>
>
> 在 2021/12/8 下午7:08, Michael S. Tsirkin 写道:
> [snip]
> > > > >
> > > > > Hi, Michael
> > > > >
> > > > > Thanks for the comment, unfortunately modify device is not an option for us
> > > > > :-(
> > > > >
> > > > > Is there any idea on how to solve this issue properly?
> > > > >
> > > > > Regards,
> > > > > Michael Wang
> > > >
> > > > By the way, there is a bug in the error message. Want to fix that?
> > >
> > > Could you please provide more detail about the bug? We'd like to help fixing
> > > it :-)
> >
> > virtio-pci 0000:14:00.0: platform bug: legacy virtio-mmio must ...
> >
> > should be virtio-pci not virtio-mmio
>
> Patch on the way~
>
> >
> >
> >
> > > Besides, I've checked that patch but it can't address our issue, we actually
> > > have this legacy pci device on arm platform, and the memory layout is
> > > unfriendly since allocation rarely providing page-address below 44bit, we
> > > understand the virtio-iommu case should not do force dma, while we don't
> > > have that so it's just working fine.
> > >
> > > Regards,
> > > Michael Wang
> >
> > Hmm wait a sec is it a physical device or a hypervisor?
> > If a physical one then doesn't it need VIRTIO_F_ORDER_PLATFORM
> > on ARM?
>
> The PCI device is virtual, I can't see how VIRTIO_F_ORDER_PLATFORM help
> address this issue, legacy pci config is 32bit but it's 36, seems like will
> never be included?
>
> Regards,
> Michael Wang
Oh, if the device is virtual then I think you should just update it please.
virtio 0.X is architecturally limited to small VMs,
if your hypervisor supports more it should emulate virtio 1.0.
> >
> >
> >
> > > >
> > > >
> > > > > >
> > > > > > > ---
> > > > > > > drivers/virtio/virtio_pci_legacy.c | 10 ++++++++++
> > > > > > > drivers/virtio/virtio_ring.c | 3 +++
> > > > > > > include/linux/virtio.h | 1 +
> > > > > > > 3 files changed, 14 insertions(+)
> > > > > > >
> > > > > > > diff --git a/drivers/virtio/virtio_pci_legacy.c
> > > > > > > b/drivers/virtio/virtio_pci_legacy.c
> > > > > > > index d62e983..11f2ebf 100644
> > > > > > > --- a/drivers/virtio/virtio_pci_legacy.c
> > > > > > > +++ b/drivers/virtio/virtio_pci_legacy.c
> > > > > > > @@ -263,6 +263,16 @@ int virtio_pci_legacy_probe(struct virtio_pci_device
> > > > > > > *vp_dev)
> > > > > > > vp_dev->setup_vq = setup_vq;
> > > > > > > vp_dev->del_vq = del_vq;
> > > > > > >
> > > > > > > + /*
> > > > > > > + * The legacy pci device requre 32bit-pfn vq,
> > > > > > > + * or setup_vq() will failed.
> > > > > > > + *
> > > > > > > + * Thus we make sure vring_use_dma_api() will
> > > > > > > + * return true during the allocation by marking
> > > > > > > + * force_dma here.
> > > > > > > + */
> > > > > > > + vp_dev->vdev.force_dma = true;
> > > > > > > +
> > > > > > > return 0;
> > > > > > >
> > > > > > > err_iomap:
> > > > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > > > > > index 3035bb6..6562e01 100644
> > > > > > > --- a/drivers/virtio/virtio_ring.c
> > > > > > > +++ b/drivers/virtio/virtio_ring.c
> > > > > > > @@ -245,6 +245,9 @@ static inline bool virtqueue_use_indirect(struct
> > > > > > > virtqueue *_vq,
> > > > > > >
> > > > > > > static bool vring_use_dma_api(struct virtio_device *vdev)
> > > > > > > {
> > > > > > > + if (vdev->force_dma)
> > > > > > > + return true;
> > > > > > > +
> > > > > > > if (!virtio_has_dma_quirk(vdev))
> > > > > > > return true;
> > > > > > >
> > > > > > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> > > > > > > index 41edbc0..a4eb29d 100644
> > > > > > > --- a/include/linux/virtio.h
> > > > > > > +++ b/include/linux/virtio.h
> > > > > > > @@ -109,6 +109,7 @@ struct virtio_device {
> > > > > > > bool failed;
> > > > > > > bool config_enabled;
> > > > > > > bool config_change_pending;
> > > > > > > + bool force_dma;
> > > > > > > spinlock_t config_lock;
> > > > > > > spinlock_t vqs_list_lock; /* Protects VQs list access */
> > > > > > > struct device dev;
> > > > > > > --
> > > > > > > 1.8.3.1
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
