RDMA/irdma: Add support for dmabuf pin memory regions

This is a followup to the EFA dmabuf[1]. Irdma driver currently does
not support on-demand-paging(ODP). So it uses habanalabs as the
dmabuf exporter, and irdma as the importer to allow for peer2peer
access through libibverbs.

In this commit, the function ib_umem_dmabuf_get_pinned() is used.
This function is introduced in EFA dmabuf[1] which allows the driver
to get a dmabuf umem which is pinned and does not require move_notify
callback implementation. The returned umem is pinned and DMA mapped
like standard cpu umems, and is released through ib_umem_release().

[1]https://lore.kernel.org/lkml/20211007114018.GD2688930@ziepe.ca/t/

Link: https://lore.kernel.org/r/20230217011425.498847-1-yanjun.zhu@intel.com
Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/irdma/verbs.c b/drivers/infiniband/hw/irdma/verbs.c
index 6982f38596c8..1b2e3e800c9a 100644
--- a/drivers/infiniband/hw/irdma/verbs.c
+++ b/drivers/infiniband/hw/irdma/verbs.c
@@ -2977,6 +2977,47 @@ error:
 	return ERR_PTR(err);
 }
 
+static struct ib_mr *irdma_reg_user_mr_dmabuf(struct ib_pd *pd, u64 start,
+					      u64 len, u64 virt,
+					      int fd, int access,
+					      struct ib_udata *udata)
+{
+	struct irdma_device *iwdev = to_iwdev(pd->device);
+	struct ib_umem_dmabuf *umem_dmabuf;
+	struct irdma_mr *iwmr;
+	int err;
+
+	if (len > iwdev->rf->sc_dev.hw_attrs.max_mr_size)
+		return ERR_PTR(-EINVAL);
+
+	umem_dmabuf = ib_umem_dmabuf_get_pinned(pd->device, start, len, fd, access);
+	if (IS_ERR(umem_dmabuf)) {
+		err = PTR_ERR(umem_dmabuf);
+		ibdev_dbg(&iwdev->ibdev, "Failed to get dmabuf umem[%d]\n", err);
+		return ERR_PTR(err);
+	}
+
+	iwmr = irdma_alloc_iwmr(&umem_dmabuf->umem, pd, virt, IRDMA_MEMREG_TYPE_MEM);
+	if (IS_ERR(iwmr)) {
+		err = PTR_ERR(iwmr);
+		goto err_release;
+	}
+
+	err = irdma_reg_user_mr_type_mem(iwmr, access);
+	if (err)
+		goto err_iwmr;
+
+	return &iwmr->ibmr;
+
+err_iwmr:
+	irdma_free_iwmr(iwmr);
+
+err_release:
+	ib_umem_release(&umem_dmabuf->umem);
+
+	return ERR_PTR(err);
+}
+
 /**
  * irdma_reg_phys_mr - register kernel physical memory
  * @pd: ibpd pointer
@@ -4483,6 +4524,7 @@ static const struct ib_device_ops irdma_dev_ops = {
 	.query_port = irdma_query_port,
 	.query_qp = irdma_query_qp,
 	.reg_user_mr = irdma_reg_user_mr,
+	.reg_user_mr_dmabuf = irdma_reg_user_mr_dmabuf,
 	.req_notify_cq = irdma_req_notify_cq,
 	.resize_cq = irdma_resize_cq,
 	INIT_RDMA_OBJ_SIZE(ib_pd, irdma_pd, ibpd),