1 files changed, 326 insertions, 0 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
new file mode 100644
index 000000000000..9f6e2bb2a269
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2022-2023 Fujitsu Ltd. All rights reserved.
+ */
+
+#include <linux/hmm.h>
+
+#include <rdma/ib_umem_odp.h>
+
+#include "rxe.h"
+
+static bool rxe_ib_invalidate_range(struct mmu_interval_notifier *mni,
+				    const struct mmu_notifier_range *range,
+				    unsigned long cur_seq)
+{
+	struct ib_umem_odp *umem_odp =
+		container_of(mni, struct ib_umem_odp, notifier);
+	unsigned long start, end;
+
+	if (!mmu_notifier_range_blockable(range))
+		return false;
+
+	mutex_lock(&umem_odp->umem_mutex);
+	mmu_interval_set_seq(mni, cur_seq);
+
+	start = max_t(u64, ib_umem_start(umem_odp), range->start);
+	end = min_t(u64, ib_umem_end(umem_odp), range->end);
+
+	/* update umem_odp->dma_list */
+	ib_umem_odp_unmap_dma_pages(umem_odp, start, end);
+
+	mutex_unlock(&umem_odp->umem_mutex);
+	return true;
+}
+
+const struct mmu_interval_notifier_ops rxe_mn_ops = {
+	.invalidate = rxe_ib_invalidate_range,
+};
+
+#define RXE_PAGEFAULT_DEFAULT 0
+#define RXE_PAGEFAULT_RDONLY BIT(0)
+#define RXE_PAGEFAULT_SNAPSHOT BIT(1)
+static int rxe_odp_do_pagefault_and_lock(struct rxe_mr *mr, u64 user_va, int bcnt, u32 flags)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	bool fault = !(flags & RXE_PAGEFAULT_SNAPSHOT);
+	u64 access_mask;
+	int np;
+
+	access_mask = ODP_READ_ALLOWED_BIT;
+	if (umem_odp->umem.writable && !(flags & RXE_PAGEFAULT_RDONLY))
+		access_mask |= ODP_WRITE_ALLOWED_BIT;
+
+	/*
+	 * ib_umem_odp_map_dma_and_lock() locks umem_mutex on success.
+	 * Callers must release the lock later to let invalidation handler
+	 * do its work again.
+	 */
+	np = ib_umem_odp_map_dma_and_lock(umem_odp, user_va, bcnt,
+					  access_mask, fault);
+	return np;
+}
+
+static int rxe_odp_init_pages(struct rxe_mr *mr)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	int ret;
+
+	ret = rxe_odp_do_pagefault_and_lock(mr, mr->umem->address,
+					    mr->umem->length,
+					    RXE_PAGEFAULT_SNAPSHOT);
+
+	if (ret >= 0)
+		mutex_unlock(&umem_odp->umem_mutex);
+
+	return ret >= 0 ? 0 : ret;
+}
+
+int rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length,
+			 u64 iova, int access_flags, struct rxe_mr *mr)
+{
+	struct ib_umem_odp *umem_odp;
+	int err;
+
+	if (!IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING))
+		return -EOPNOTSUPP;
+
+	rxe_mr_init(access_flags, mr);
+
+	if (!start && length == U64_MAX) {
+		if (iova != 0)
+			return -EINVAL;
+		if (!(rxe->attr.odp_caps.general_caps & IB_ODP_SUPPORT_IMPLICIT))
+			return -EINVAL;
+
+		/* Never reach here, for implicit ODP is not implemented. */
+	}
+
+	umem_odp = ib_umem_odp_get(&rxe->ib_dev, start, length, access_flags,
+				   &rxe_mn_ops);
+	if (IS_ERR(umem_odp)) {
+		rxe_dbg_mr(mr, "Unable to create umem_odp err = %d\n",
+			   (int)PTR_ERR(umem_odp));
+		return PTR_ERR(umem_odp);
+	}
+
+	umem_odp->private = mr;
+
+	mr->umem = &umem_odp->umem;
+	mr->access = access_flags;
+	mr->ibmr.length = length;
+	mr->ibmr.iova = iova;
+	mr->page_offset = ib_umem_offset(&umem_odp->umem);
+
+	err = rxe_odp_init_pages(mr);
+	if (err) {
+		ib_umem_odp_release(umem_odp);
+		return err;
+	}
+
+	mr->state = RXE_MR_STATE_VALID;
+	mr->ibmr.type = IB_MR_TYPE_USER;
+
+	return err;
+}
+
+static inline bool rxe_check_pagefault(struct ib_umem_odp *umem_odp,
+				       u64 iova, int length, u32 perm)
+{
+	bool need_fault = false;
+	u64 addr;
+	int idx;
+
+	addr = iova & (~(BIT(umem_odp->page_shift) - 1));
+
+	/* Skim through all pages that are to be accessed. */
+	while (addr < iova + length) {
+		idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+
+		if (!(umem_odp->dma_list[idx] & perm)) {
+			need_fault = true;
+			break;
+		}
+
+		addr += BIT(umem_odp->page_shift);
+	}
+	return need_fault;
+}
+
+static int rxe_odp_map_range_and_lock(struct rxe_mr *mr, u64 iova, int length, u32 flags)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	bool need_fault;
+	u64 perm;
+	int err;
+
+	if (unlikely(length < 1))
+		return -EINVAL;
+
+	perm = ODP_READ_ALLOWED_BIT;
+	if (!(flags & RXE_PAGEFAULT_RDONLY))
+		perm |= ODP_WRITE_ALLOWED_BIT;
+
+	mutex_lock(&umem_odp->umem_mutex);
+
+	need_fault = rxe_check_pagefault(umem_odp, iova, length, perm);
+	if (need_fault) {
+		mutex_unlock(&umem_odp->umem_mutex);
+
+		/* umem_mutex is locked on success. */
+		err = rxe_odp_do_pagefault_and_lock(mr, iova, length,
+						    flags);
+		if (err < 0)
+			return err;
+
+		need_fault = rxe_check_pagefault(umem_odp, iova, length, perm);
+		if (need_fault)
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
+			     int length, enum rxe_mr_copy_dir dir)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	struct page *page;
+	int idx, bytes;
+	size_t offset;
+	u8 *user_va;
+
+	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+	offset = iova & (BIT(umem_odp->page_shift) - 1);
+
+	while (length > 0) {
+		u8 *src, *dest;
+
+		page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
+		user_va = kmap_local_page(page);
+		if (!user_va)
+			return -EFAULT;
+
+		src = (dir == RXE_TO_MR_OBJ) ? addr : user_va;
+		dest = (dir == RXE_TO_MR_OBJ) ? user_va : addr;
+
+		bytes = BIT(umem_odp->page_shift) - offset;
+		if (bytes > length)
+			bytes = length;
+
+		memcpy(dest, src, bytes);
+		kunmap_local(user_va);
+
+		length  -= bytes;
+		idx++;
+		offset = 0;
+	}
+
+	return 0;
+}
+
+int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
+		    enum rxe_mr_copy_dir dir)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	u32 flags = RXE_PAGEFAULT_DEFAULT;
+	int err;
+
+	if (length == 0)
+		return 0;
+
+	if (unlikely(!mr->umem->is_odp))
+		return -EOPNOTSUPP;
+
+	switch (dir) {
+	case RXE_TO_MR_OBJ:
+		break;
+
+	case RXE_FROM_MR_OBJ:
+		flags |= RXE_PAGEFAULT_RDONLY;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	err = rxe_odp_map_range_and_lock(mr, iova, length, flags);
+	if (err)
+		return err;
+
+	err =  __rxe_odp_mr_copy(mr, iova, addr, length, dir);
+
+	mutex_unlock(&umem_odp->umem_mutex);
+
+	return err;
+}
+
+static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
+				u64 compare, u64 swap_add, u64 *orig_val)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	unsigned int page_offset;
+	struct page *page;
+	unsigned int idx;
+	u64 value;
+	u64 *va;
+	int err;
+
+	if (unlikely(mr->state != RXE_MR_STATE_VALID)) {
+		rxe_dbg_mr(mr, "mr not in valid state\n");
+		return RESPST_ERR_RKEY_VIOLATION;
+	}
+
+	err = mr_check_range(mr, iova, sizeof(value));
+	if (err) {
+		rxe_dbg_mr(mr, "iova out of range\n");
+		return RESPST_ERR_RKEY_VIOLATION;
+	}
+
+	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+	page_offset = iova & (BIT(umem_odp->page_shift) - 1);
+	page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
+	if (!page)
+		return RESPST_ERR_RKEY_VIOLATION;
+
+	if (unlikely(page_offset & 0x7)) {
+		rxe_dbg_mr(mr, "iova not aligned\n");
+		return RESPST_ERR_MISALIGNED_ATOMIC;
+	}
+
+	va = kmap_local_page(page);
+
+	spin_lock_bh(&atomic_ops_lock);
+	value = *orig_val = va[page_offset >> 3];
+
+	if (opcode == IB_OPCODE_RC_COMPARE_SWAP) {
+		if (value == compare)
+			va[page_offset >> 3] = swap_add;
+	} else {
+		value += swap_add;
+		va[page_offset >> 3] = value;
+	}
+	spin_unlock_bh(&atomic_ops_lock);
+
+	kunmap_local(va);
+
+	return 0;
+}
+
+int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
+			 u64 compare, u64 swap_add, u64 *orig_val)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	int err;
+
+	err = rxe_odp_map_range_and_lock(mr, iova, sizeof(char),
+					 RXE_PAGEFAULT_DEFAULT);
+	if (err < 0)
+		return RESPST_ERR_RKEY_VIOLATION;
+
+	err = rxe_odp_do_atomic_op(mr, iova, opcode, compare, swap_add,
+				   orig_val);
+	mutex_unlock(&umem_odp->umem_mutex);
+
+	return err;
+}