> The NVDIMM region could be available before the virtio_device_ready() > that is called by virtio_dev_probe(). This means the driver tries to > use device before DRIVER_OK which violates the spec, fixing this by > set device ready before the nvdimm_pmem_region_create(). > > Note that this means the virtio_pmem_host_ack() could be triggered > before the creation of the nd region, this is safe since the > virtio_pmem_host_ack() since pmem_lock has been initialized and we > check if we've added any buffer before trying to proceed. > > Fixes 6e84200c0a29 ("virtio-pmem: Add virtio pmem driver") > Signed-off-by: Jason Wang <jasow...@redhat.com> > --- > drivers/nvdimm/virtio_pmem.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c > index 48f8327d0431..173f2f5adaea 100644 > --- a/drivers/nvdimm/virtio_pmem.c > +++ b/drivers/nvdimm/virtio_pmem.c > @@ -84,6 +84,17 @@ static int virtio_pmem_probe(struct virtio_device *vdev) > ndr_desc.provider_data = vdev; > set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags); > set_bit(ND_REGION_ASYNC, &ndr_desc.flags); > + /* > + * The NVDIMM region could be available before the > + * virtio_device_ready() that is called by > + * virtio_dev_probe(), so we set device ready here. > + * > + * The callback - virtio_pmem_host_ack() is safe to be called > + * before the nvdimm_pmem_region_create() since the pmem_lock > + * has been initialized and legality of a used buffer is > + * validated before moving forward. > + */ > + virtio_device_ready(vdev); > nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus, &ndr_desc); > if (!nd_region) { > dev_err(&vdev->dev, "failed to create nvdimm region\n"); > @@ -92,6 +103,7 @@ static int virtio_pmem_probe(struct virtio_device *vdev) > } > return 0; > out_nd: > + virtio_reset_device(vdev); > nvdimm_bus_unregister(vpmem->nvdimm_bus); > out_vq: > vdev->config->del_vqs(vdev);
IIRC Similar fix was submitted by msft in the past while proposing support for PCI BAR with virtio pmem and I tested it. Feel free to add. Acked-by: Pankaj Gupta <pankaj.gu...@amd.com>