On Mon, Jul 19, 2021 at 05:17:00PM -0400, Michael S. Tsirkin wrote: > On Thu, Jul 15, 2021 at 03:35:05PM -0700, Taylor Stark wrote: > > Update virtio-pmem to allow for the pmem region to be specified in either > > guest absolute terms or as a PCI BAR-relative address. This is required > > to support virtio-pmem in Hyper-V, since Hyper-V only allows PCI devices > > to operate on PCI memory ranges defined via BARs. > > > > Virtio-pmem will check for a shared memory window and use that if found, > > else it will fallback to using the guest absolute addresses in > > virtio_pmem_config. This was chosen over defining a new feature bit, > > since it's similar to how virtio-fs is configured. > > > > Signed-off-by: Taylor Stark <[email protected]> > > This needs to be added to the device spec too. > Can you send a spec patch please? > It's a subscriber-only list [email protected]
Absolutely! I tried looking on the virtio-spec repo on github but I couldn't find a spec for virtio-pmem to update. There is this issue (https://github.com/oasis-tcs/virtio-spec/issues/78) which seems to indicate the virtio-pmem spec hasn't been added yet. Any suggestions for where to send a patch? Thanks, Taylor > > --- > > drivers/nvdimm/virtio_pmem.c | 21 +++++++++++++++++---- > > drivers/nvdimm/virtio_pmem.h | 3 +++ > > 2 files changed, 20 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c > > index 726c7354d465..43c1d835a449 100644 > > --- a/drivers/nvdimm/virtio_pmem.c > > +++ b/drivers/nvdimm/virtio_pmem.c > > @@ -37,6 +37,8 @@ static int virtio_pmem_probe(struct virtio_device *vdev) > > struct virtio_pmem *vpmem; > > struct resource res; > > int err = 0; > > + bool have_shm_region; > > + struct virtio_shm_region pmem_region; > > > > if (!vdev->config->get) { > > dev_err(&vdev->dev, "%s failure: config access disabled\n", > > @@ -58,10 +60,21 @@ static int virtio_pmem_probe(struct virtio_device *vdev) > > goto out_err; > > } > > > > - virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, > > - start, &vpmem->start); > > - virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, > > - size, &vpmem->size); > > + /* Retrieve the pmem device's address and size. It may have been > > supplied > > + * as a PCI BAR-relative shared memory region, or as a guest absolute > > address. > > + */ > > + have_shm_region = virtio_get_shm_region(vpmem->vdev, &pmem_region, > > + > > VIRTIO_PMEM_SHMCAP_ID_PMEM_REGION); > > + > > + if (have_shm_region) { > > + vpmem->start = pmem_region.addr; > > + vpmem->size = pmem_region.len; > > + } else { > > + virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, > > + start, &vpmem->start); > > + virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, > > + size, &vpmem->size); > > + } > > > > res.start = vpmem->start; > > res.end = vpmem->start + vpmem->size - 1; > > diff --git a/drivers/nvdimm/virtio_pmem.h b/drivers/nvdimm/virtio_pmem.h > > index 0dddefe594c4..62bb564e81cb 100644 > > --- a/drivers/nvdimm/virtio_pmem.h > > +++ b/drivers/nvdimm/virtio_pmem.h > > @@ -50,6 +50,9 @@ struct virtio_pmem { > > __u64 size; > > }; > > > > +/* For the id field in virtio_pci_shm_cap */ > > +#define VIRTIO_PMEM_SHMCAP_ID_PMEM_REGION 0 > > + > > void virtio_pmem_host_ack(struct virtqueue *vq); > > int async_pmem_flush(struct nd_region *nd_region, struct bio *bio); > > #endif > > -- > > 2.32.0
