Messages in this thread | | | Date | Tue, 7 Dec 2021 17:09:56 +0800 | Subject | Re: [RFC PATCH] virtio: make sure legacy pci device gain 32bit-pfn vq | From | 王贇 <> |
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在 2021/12/7 下午4:13, Michael S. Tsirkin 写道: > On Tue, Dec 07, 2021 at 03:51:45PM +0800, 王贇 wrote: >> We observed issues like: >> virtio-pci 0000:14:00.0: platform bug: legacy virtio-mmio must >> not be used with RAM above 0x4000GB >> >> when we have a legacy pci device which desired 32bit-pfn vq >> but gain 64bit-pfn instead, lead into the failure of probe. >> >> vring_use_dma_api() is playing the key role in here, to help the >> allocation process understand which kind of vq it should alloc, >> however, it failed to take care the legacy pci device, which only >> have 32bit feature flag and can never have VIRTIO_F_ACCESS_PLATFORM >> setted. >> >> This patch introduce force_dma flag to help vring_use_dma_api() >> understanding the requirement better, to avoid the failing. >> >> Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com> > > This will break configs where the device appears behind > a virtual iommu, so this won't fly. > Just make your device support 1.0, eh?
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
> >> --- >> 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
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