[PATCH v11 4/4] RDMA/mlx5: Support dma-buf based userspace memory region
Jianxin Xiong
jianxin.xiong at intel.com
Mon Nov 23 17:51:59 UTC 2020
Implement the new driver method 'reg_user_mr_dmabuf'. Utilize the core
functions to import dma-buf based memory region and update the mappings.
Add code to handle dma-buf related page fault.
Signed-off-by: Jianxin Xiong <jianxin.xiong at intel.com>
Reviewed-by: Sean Hefty <sean.hefty at intel.com>
Acked-by: Michael J. Ruhl <michael.j.ruhl at intel.com>
Acked-by: Christian Koenig <christian.koenig at amd.com>
Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
drivers/infiniband/hw/mlx5/main.c | 2 +
drivers/infiniband/hw/mlx5/mlx5_ib.h | 18 +++++
drivers/infiniband/hw/mlx5/mr.c | 127 +++++++++++++++++++++++++++++++++--
drivers/infiniband/hw/mlx5/odp.c | 86 ++++++++++++++++++++++--
4 files changed, 224 insertions(+), 9 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 36b15a0..e647ea4 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/*
* Copyright (c) 2013-2020, Mellanox Technologies inc. All rights reserved.
+ * Copyright (c) 2020, Intel Corporation. All rights reserved.
*/
#include <linux/debugfs.h>
@@ -4055,6 +4056,7 @@ static int mlx5_ib_enable_driver(struct ib_device *dev)
.query_srq = mlx5_ib_query_srq,
.query_ucontext = mlx5_ib_query_ucontext,
.reg_user_mr = mlx5_ib_reg_user_mr,
+ .reg_user_mr_dmabuf = mlx5_ib_reg_user_mr_dmabuf,
.req_notify_cq = mlx5_ib_arm_cq,
.rereg_user_mr = mlx5_ib_rereg_user_mr,
.resize_cq = mlx5_ib_resize_cq,
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index bb44080..3ef6872 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
/*
* Copyright (c) 2013-2020, Mellanox Technologies inc. All rights reserved.
+ * Copyright (c) 2020, Intel Corporation. All rights reserved.
*/
#ifndef MLX5_IB_H
@@ -665,6 +666,12 @@ static inline bool is_odp_mr(struct mlx5_ib_mr *mr)
mr->umem->is_odp;
}
+static inline bool is_dmabuf_mr(struct mlx5_ib_mr *mr)
+{
+ return IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING) && mr->umem &&
+ mr->umem->is_dmabuf;
+}
+
struct mlx5_ib_mw {
struct ib_mw ibmw;
struct mlx5_core_mkey mmkey;
@@ -1200,6 +1207,10 @@ int mlx5_ib_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
u64 virt_addr, int access_flags,
struct ib_udata *udata);
+struct ib_mr *mlx5_ib_reg_user_mr_dmabuf(struct ib_pd *pd, u64 start,
+ u64 length, u64 virt_addr,
+ int fd, int access_flags,
+ struct ib_udata *udata);
int mlx5_ib_advise_mr(struct ib_pd *pd,
enum ib_uverbs_advise_mr_advice advice,
u32 flags,
@@ -1210,11 +1221,13 @@ int mlx5_ib_advise_mr(struct ib_pd *pd,
int mlx5_ib_dealloc_mw(struct ib_mw *mw);
int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
int page_shift, int flags);
+int mlx5_ib_update_mr_pas(struct mlx5_ib_mr *mr, unsigned int flags);
struct mlx5_ib_mr *mlx5_ib_alloc_implicit_mr(struct mlx5_ib_pd *pd,
struct ib_udata *udata,
int access_flags);
void mlx5_ib_free_implicit_mr(struct mlx5_ib_mr *mr);
void mlx5_ib_fence_odp_mr(struct mlx5_ib_mr *mr);
+void mlx5_ib_fence_dmabuf_mr(struct mlx5_ib_mr *mr);
int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
u64 length, u64 virt_addr, int access_flags,
struct ib_pd *pd, struct ib_udata *udata);
@@ -1306,6 +1319,7 @@ int mlx5_ib_advise_mr_prefetch(struct ib_pd *pd,
enum ib_uverbs_advise_mr_advice advice,
u32 flags, struct ib_sge *sg_list, u32 num_sge);
int mlx5_ib_init_odp_mr(struct mlx5_ib_mr *mr, bool enable);
+int mlx5_ib_init_dmabuf_mr(struct mlx5_ib_mr *mr);
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
static inline void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev)
{
@@ -1331,6 +1345,10 @@ static inline int mlx5_ib_init_odp_mr(struct mlx5_ib_mr *mr, bool enable)
{
return -EOPNOTSUPP;
}
+static inline int mlx5_ib_init_dmabuf_mr(struct mlx5_ib_mr *mr)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
extern const struct mmu_interval_notifier_ops mlx5_mn_ops;
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 9f653b4..b7c869c 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1,5 +1,6 @@
/*
* Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2020, Intel Corporation. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
@@ -36,6 +37,8 @@
#include <linux/debugfs.h>
#include <linux/export.h>
#include <linux/delay.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-resv.h>
#include <rdma/ib_umem.h>
#include <rdma/ib_umem_odp.h>
#include <rdma/ib_verbs.h>
@@ -957,6 +960,16 @@ static struct mlx5_cache_ent *mr_cache_ent_from_order(struct mlx5_ib_dev *dev,
return &cache->ent[order];
}
+static unsigned int mlx5_umem_dmabuf_default_pgsz(struct ib_umem *umem,
+ u64 iova)
+{
+ if ((iova ^ umem->address) & (PAGE_SIZE - 1))
+ return 0;
+
+ umem->iova = iova;
+ return PAGE_SIZE;
+}
+
static struct mlx5_ib_mr *alloc_mr_from_cache(struct ib_pd *pd,
struct ib_umem *umem, u64 iova,
int access_flags)
@@ -966,7 +979,10 @@ static struct mlx5_ib_mr *alloc_mr_from_cache(struct ib_pd *pd,
struct mlx5_ib_mr *mr;
unsigned int page_size;
- page_size = mlx5_umem_find_best_pgsz(umem, mkc, log_page_size, 0, iova);
+ if (umem->is_dmabuf)
+ page_size = mlx5_umem_dmabuf_default_pgsz(umem, iova);
+ else
+ page_size = mlx5_umem_find_best_pgsz(umem, mkc, log_page_size, 0, iova);
if (WARN_ON(!page_size))
return ERR_PTR(-EINVAL);
ent = mr_cache_ent_from_order(
@@ -1212,8 +1228,10 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
/*
* Send the DMA list to the HW for a normal MR using UMR.
+ * Dmabuf MR is handled in a similar way, except that the MLX5_IB_UPD_XLT_ZAP
+ * flag may be used.
*/
-static int mlx5_ib_update_mr_pas(struct mlx5_ib_mr *mr, unsigned int flags)
+int mlx5_ib_update_mr_pas(struct mlx5_ib_mr *mr, unsigned int flags)
{
struct mlx5_ib_dev *dev = mr->dev;
struct device *ddev = dev->ib_dev.dev.parent;
@@ -1255,6 +1273,10 @@ static int mlx5_ib_update_mr_pas(struct mlx5_ib_mr *mr, unsigned int flags)
cur_mtt->ptag =
cpu_to_be64(rdma_block_iter_dma_address(&biter) |
MLX5_IB_MTT_PRESENT);
+
+ if (mr->umem->is_dmabuf && (flags & MLX5_IB_UPD_XLT_ZAP))
+ cur_mtt->ptag = 0;
+
cur_mtt++;
}
@@ -1291,8 +1313,11 @@ static struct mlx5_ib_mr *reg_create(struct ib_mr *ibmr, struct ib_pd *pd,
int err;
bool pg_cap = !!(MLX5_CAP_GEN(dev->mdev, pg));
- page_size =
- mlx5_umem_find_best_pgsz(umem, mkc, log_page_size, 0, iova);
+ if (umem->is_dmabuf)
+ page_size = mlx5_umem_dmabuf_default_pgsz(umem, iova);
+ else
+ page_size = mlx5_umem_find_best_pgsz(umem, mkc, log_page_size,
+ 0, iova);
if (WARN_ON(!page_size))
return ERR_PTR(-EINVAL);
@@ -1581,6 +1606,96 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
return ERR_PTR(err);
}
+static void mlx5_ib_dmabuf_invalidate_cb(struct dma_buf_attachment *attach)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = attach->importer_priv;
+ struct mlx5_ib_mr *mr = umem_dmabuf->private;
+
+ dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+ if (!umem_dmabuf->sgt)
+ return;
+
+ mlx5_ib_update_mr_pas(mr, MLX5_IB_UPD_XLT_ZAP);
+ ib_umem_dmabuf_unmap_pages(umem_dmabuf);
+}
+
+static struct dma_buf_attach_ops mlx5_ib_dmabuf_attach_ops = {
+ .allow_peer2peer = 1,
+ .move_notify = mlx5_ib_dmabuf_invalidate_cb,
+};
+
+struct ib_mr *mlx5_ib_reg_user_mr_dmabuf(struct ib_pd *pd, u64 offset,
+ u64 length, u64 virt_addr,
+ int fd, int access_flags,
+ struct ib_udata *udata)
+{
+ struct mlx5_ib_dev *dev = to_mdev(pd->device);
+ struct mlx5_ib_mr *mr = NULL;
+ struct ib_umem *umem;
+ int err;
+
+ if (!IS_ENABLED(CONFIG_INFINIBAND_USER_MEM))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ mlx5_ib_dbg(dev,
+ "offset 0x%llx, virt_addr 0x%llx, length 0x%llx, fd %d, access_flags 0x%x\n",
+ offset, virt_addr, length, fd, access_flags);
+
+ if (!mlx5_ib_can_load_pas_with_umr(dev, length))
+ return ERR_PTR(-EINVAL);
+
+ umem = ib_umem_dmabuf_get(&dev->ib_dev, offset, length, fd, access_flags,
+ &mlx5_ib_dmabuf_attach_ops);
+ if (IS_ERR(umem)) {
+ mlx5_ib_dbg(dev, "umem get failed (%ld)\n", PTR_ERR(umem));
+ return ERR_PTR(PTR_ERR(umem));
+ }
+
+ mr = alloc_mr_from_cache(pd, umem, virt_addr, access_flags);
+ if (IS_ERR(mr))
+ mr = NULL;
+
+ if (!mr) {
+ mutex_lock(&dev->slow_path_mutex);
+ mr = reg_create(NULL, pd, umem, virt_addr, access_flags,
+ false);
+ mutex_unlock(&dev->slow_path_mutex);
+ }
+
+ if (IS_ERR(mr)) {
+ err = PTR_ERR(mr);
+ goto error;
+ }
+
+ mlx5_ib_dbg(dev, "mkey 0x%x\n", mr->mmkey.key);
+
+ mr->umem = umem;
+ atomic_add(ib_umem_num_pages(mr->umem), &dev->mdev->priv.reg_pages);
+ set_mr_fields(dev, mr, length, access_flags);
+
+ to_ib_umem_dmabuf(umem)->private = mr;
+ init_waitqueue_head(&mr->q_deferred_work);
+ atomic_set(&mr->num_deferred_work, 0);
+ err = xa_err(xa_store(&dev->odp_mkeys,
+ mlx5_base_mkey(mr->mmkey.key), &mr->mmkey,
+ GFP_KERNEL));
+ if (err) {
+ dereg_mr(dev, mr);
+ return ERR_PTR(err);
+ }
+
+ err = mlx5_ib_init_dmabuf_mr(mr);
+ if (err) {
+ dereg_mr(dev, mr);
+ return ERR_PTR(err);
+ }
+ return &mr->ibmr;
+error:
+ ib_umem_release(umem);
+ return ERR_PTR(err);
+}
+
/**
* mlx5_mr_cache_invalidate - Fence all DMA on the MR
* @mr: The MR to fence
@@ -1649,7 +1764,7 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
if (!mr->umem)
return -EINVAL;
- if (is_odp_mr(mr))
+ if (is_odp_mr(mr) || is_dmabuf_mr(mr))
return -EOPNOTSUPP;
if (flags & IB_MR_REREG_TRANS) {
@@ -1812,6 +1927,8 @@ static void dereg_mr(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)
/* Stop all DMA */
if (is_odp)
mlx5_ib_fence_odp_mr(mr);
+ else if (is_dmabuf_mr(mr))
+ mlx5_ib_fence_dmabuf_mr(mr);
else
clean_mr(dev, mr);
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 5c853ec..41aeb92 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -33,6 +33,8 @@
#include <rdma/ib_umem.h>
#include <rdma/ib_umem_odp.h>
#include <linux/kernel.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-resv.h>
#include "mlx5_ib.h"
#include "cmd.h"
@@ -664,6 +666,37 @@ void mlx5_ib_fence_odp_mr(struct mlx5_ib_mr *mr)
dma_fence_odp_mr(mr);
}
+/**
+ * mlx5_ib_fence_dmabuf_mr - Stop all access to the dmabuf MR
+ * @mr: to fence
+ *
+ * On return no parallel threads will be touching this MR and no DMA will be
+ * active.
+ */
+void mlx5_ib_fence_dmabuf_mr(struct mlx5_ib_mr *mr)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(mr->umem);
+
+ /* Prevent new page faults and prefetch requests from succeeding */
+ xa_erase(&mr->dev->odp_mkeys, mlx5_base_mkey(mr->mmkey.key));
+
+ /* Wait for all running page-fault handlers to finish. */
+ synchronize_srcu(&mr->dev->odp_srcu);
+
+ wait_event(mr->q_deferred_work, !atomic_read(&mr->num_deferred_work));
+
+ dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+ mlx5_mr_cache_invalidate(mr);
+ umem_dmabuf->private = NULL;
+ ib_umem_dmabuf_unmap_pages(umem_dmabuf);
+ dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+
+ if (!mr->cache_ent) {
+ mlx5_core_destroy_mkey(mr->dev->mdev, &mr->mmkey);
+ WARN_ON(mr->descs);
+ }
+}
+
#define MLX5_PF_FLAGS_DOWNGRADE BIT(1)
#define MLX5_PF_FLAGS_SNAPSHOT BIT(2)
#define MLX5_PF_FLAGS_ENABLE BIT(3)
@@ -797,6 +830,41 @@ static int pagefault_implicit_mr(struct mlx5_ib_mr *imr,
return ret;
}
+static int pagefault_dmabuf_mr(struct mlx5_ib_mr *mr, size_t bcnt,
+ u32 *bytes_mapped, u32 flags)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(mr->umem);
+ u32 xlt_flags = 0;
+ int err;
+ unsigned int page_size;
+
+ if (flags & MLX5_PF_FLAGS_ENABLE)
+ xlt_flags |= MLX5_IB_UPD_XLT_ENABLE;
+
+ dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+ err = ib_umem_dmabuf_map_pages(umem_dmabuf);
+ if (!err) {
+ page_size = mlx5_umem_find_best_pgsz(&umem_dmabuf->umem, mkc,
+ log_page_size, 0,
+ umem_dmabuf->umem.iova);
+ if (unlikely(page_size < PAGE_SIZE)) {
+ ib_umem_dmabuf_unmap_pages(umem_dmabuf);
+ err = -EINVAL;
+ } else {
+ err = mlx5_ib_update_mr_pas(mr, xlt_flags);
+ }
+ }
+ dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+
+ if (err)
+ return err;
+
+ if (bytes_mapped)
+ *bytes_mapped += bcnt;
+
+ return ib_umem_num_pages(mr->umem);
+}
+
/*
* Returns:
* -EFAULT: The io_virt->bcnt is not within the MR, it covers pages that are
@@ -815,6 +883,9 @@ static int pagefault_mr(struct mlx5_ib_mr *mr, u64 io_virt, size_t bcnt,
if (unlikely(io_virt < mr->mmkey.iova))
return -EFAULT;
+ if (is_dmabuf_mr(mr))
+ return pagefault_dmabuf_mr(mr, bcnt, bytes_mapped, flags);
+
if (!odp->is_implicit_odp) {
u64 user_va;
@@ -845,6 +916,16 @@ int mlx5_ib_init_odp_mr(struct mlx5_ib_mr *mr, bool enable)
return ret >= 0 ? 0 : ret;
}
+int mlx5_ib_init_dmabuf_mr(struct mlx5_ib_mr *mr)
+{
+ int ret;
+
+ ret = pagefault_dmabuf_mr(mr, mr->umem->length, NULL,
+ MLX5_PF_FLAGS_ENABLE);
+
+ return ret >= 0 ? 0 : ret;
+}
+
struct pf_frame {
struct pf_frame *next;
u32 key;
@@ -1747,7 +1828,6 @@ static void destroy_prefetch_work(struct prefetch_mr_work *work)
{
struct mlx5_ib_dev *dev = to_mdev(pd->device);
struct mlx5_core_mkey *mmkey;
- struct ib_umem_odp *odp;
struct mlx5_ib_mr *mr;
lockdep_assert_held(&dev->odp_srcu);
@@ -1761,11 +1841,9 @@ static void destroy_prefetch_work(struct prefetch_mr_work *work)
if (mr->ibmr.pd != pd)
return NULL;
- odp = to_ib_umem_odp(mr->umem);
-
/* prefetch with write-access must be supported by the MR */
if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE &&
- !odp->umem.writable)
+ !mr->umem->writable)
return NULL;
return mr;
--
1.8.3.1
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