[RFC PATCH 6/8 v2] IB/mlx5/hmm: add mlx5 HMM device initialization and callback v3.

From: JÃrÃme Glisse
Date: Thu Aug 13 2015 - 15:22:27 EST

This add the core HMM callback for mlx5 device driver and initialize
the HMM device for the mlx5 infiniband device driver.

Changed since v1:
- Adapt to new hmm_mirror lifetime rules.
- HMM_ISDIRTY no longer exist.

Changed since v2:
- Adapt to HMM page table changes.

Signed-off-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
drivers/infiniband/core/umem_odp.c | 10 +-
drivers/infiniband/hw/mlx5/main.c | 5 +
drivers/infiniband/hw/mlx5/mem.c | 38 ++++++++
drivers/infiniband/hw/mlx5/mlx5_ib.h | 17 ++++
drivers/infiniband/hw/mlx5/mr.c | 7 ++
drivers/infiniband/hw/mlx5/odp.c | 174 +++++++++++++++++++++++++++++++++++
include/rdma/ib_umem_odp.h | 17 ++++
7 files changed, 264 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index bcbc2c2..b7dd8228 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -132,7 +132,7 @@ int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem)
return -ENOMEM;
}
kref_init(&ib_mirror->kref);
- init_rwsem(&ib_mirror->hmm_mr_rwsem);
+ init_rwsem(&ib_mirror->umem_rwsem);
ib_mirror->umem_tree = RB_ROOT;
ib_mirror->ib_device = ib_device;

@@ -149,10 +149,11 @@ int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem)
context->ib_mirror = ib_mirror_ref(ib_mirror);
}
mutex_unlock(&ib_device->hmm_mutex);
- umem->odp_data.ib_mirror = ib_mirror;
+ umem->odp_data->ib_mirror = ib_mirror;

down_write(&ib_mirror->umem_rwsem);
- rbt_ib_umem_insert(&umem->odp_data->interval_tree, &mirror->umem_tree);
+ rbt_ib_umem_insert(&umem->odp_data->interval_tree,
+ &ib_mirror->umem_tree);
up_write(&ib_mirror->umem_rwsem);

mmput(mm);
@@ -178,7 +179,8 @@ void ib_umem_odp_release(struct ib_umem *umem)
* range covered by one and only one umem while holding the umem rwsem.
*/
down_write(&ib_mirror->umem_rwsem);
- rbt_ib_umem_remove(&umem->odp_data->interval_tree, &mirror->umem_tree);
+ rbt_ib_umem_remove(&umem->odp_data->interval_tree,
+ &ib_mirror->umem_tree);
up_write(&ib_mirror->umem_rwsem);

ib_mirror_unref(ib_mirror);
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index da31c70..32ed2f1 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1530,6 +1530,9 @@ static void *mlx5_ib_add(struct mlx5_core_dev *mdev)
if (err)
goto err_rsrc;

+ /* If HMM initialization fails we just do not enable odp. */
+ mlx5_dev_init_odp_hmm(&dev->ib_dev, &mdev->pdev->dev);
+
err = ib_register_device(&dev->ib_dev, NULL);
if (err)
goto err_odp;
@@ -1554,6 +1557,7 @@ err_umrc:

err_dev:
ib_unregister_device(&dev->ib_dev);
+ mlx5_dev_fini_odp_hmm(&dev->ib_dev);

err_odp:
mlx5_ib_odp_remove_one(dev);
@@ -1573,6 +1577,7 @@ static void mlx5_ib_remove(struct mlx5_core_dev *mdev, void *context)

ib_unregister_device(&dev->ib_dev);
destroy_umrc_res(dev);
+ mlx5_dev_fini_odp_hmm(&dev->ib_dev);
mlx5_ib_odp_remove_one(dev);
destroy_dev_resources(&dev->devr);
ib_dealloc_device(&dev->ib_dev);
diff --git a/drivers/infiniband/hw/mlx5/mem.c b/drivers/infiniband/hw/mlx5/mem.c
index 19354b6..0d74eac 100644
--- a/drivers/infiniband/hw/mlx5/mem.c
+++ b/drivers/infiniband/hw/mlx5/mem.c
@@ -154,6 +154,8 @@ void __mlx5_ib_populate_pas(struct mlx5_ib_dev *dev, struct ib_umem *umem,
__be64 *pas, int access_flags, void *data)
{
unsigned long umem_page_shift = ilog2(umem->page_size);
+ unsigned long start = ib_umem_start(umem) + (offset << PAGE_SHIFT);
+ unsigned long end = start + (num_pages << PAGE_SHIFT);
int shift = page_shift - umem_page_shift;
int mask = (1 << shift) - 1;
int i, k;
@@ -164,6 +166,42 @@ void __mlx5_ib_populate_pas(struct mlx5_ib_dev *dev, struct ib_umem *umem,
int entry;
#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING)
#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM)
+ if (umem->odp_data) {
+ struct ib_mirror *ib_mirror = umem->odp_data->ib_mirror;
+ struct hmm_mirror *mirror = &ib_mirror->base;
+ struct hmm_pt_iter *iter = data, local_iter;
+ unsigned long addr;
+
+ if (iter == NULL) {
+ iter = &local_iter;
+ hmm_pt_iter_init(iter, &mirror->pt);
+ }
+
+ for (i=0, addr=start; i < num_pages; ++i, addr+=PAGE_SIZE) {
+ unsigned long next = end;
+ dma_addr_t *ptep, pte;
+
+ /* Get and lock pointer to mirror page table. */
+ ptep = hmm_pt_iter_lookup(iter, addr, &next);
+ pte = ptep ? *ptep : 0;
+ /*
+ * HMM will not have any page tables set up, if this
+ * function is called before page faults have happened
+ * on the MR. In that case, we don't have PA's yet, so
+ * just set each one to zero and continue on. The hw
+ * will trigger a page fault.
+ */
+ if (hmm_pte_test_valid_dma(&pte))
+ pas[i] = cpu_to_be64(umem_dma_to_mtt(pte));
+ else
+ pas[i] = (__be64)0;
+ }
+
+ if (iter == &local_iter)
+ hmm_pt_iter_fini(iter);
+
+ return;
+ }
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */
const bool odp = umem->odp_data != NULL;

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 28b500a..ba2d46e 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -635,6 +635,7 @@ int mlx5_ib_check_mr_status(struct ib_mr *ibmr, u32 check_mask,
struct ib_mr_status *mr_status);

#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING)
+
extern struct workqueue_struct *mlx5_ib_page_fault_wq;

void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev);
@@ -649,11 +650,16 @@ void mlx5_ib_qp_disable_pagefaults(struct mlx5_ib_qp *qp);
void mlx5_ib_qp_enable_pagefaults(struct mlx5_ib_qp *qp);

#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM)
+void mlx5_dev_init_odp_hmm(struct ib_device *ib_dev, struct device *dev);
+void mlx5_dev_fini_odp_hmm(struct ib_device *ib_dev);
+int mlx5_ib_umem_invalidate(struct ib_umem *umem, u64 start,
+ u64 end, void *cookie);
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */
void mlx5_ib_invalidate_range(struct ib_umem *umem, unsigned long start,
unsigned long end);
#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */

+
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
static inline void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev)
{
@@ -690,4 +696,15 @@ static inline u8 convert_access(int acc)
#define MLX5_MAX_UMR_SHIFT 16
#define MLX5_MAX_UMR_PAGES (1 << MLX5_MAX_UMR_SHIFT)

+#ifndef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM
+static inline void mlx5_dev_init_odp_hmm(struct ib_device *ib_dev,
+ struct device *dev)
+{
+}
+
+static inline void mlx5_dev_fini_odp_hmm(struct ib_device *ib_dev)
+{
+}
+#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */
+
#endif /* MLX5_IB_H */
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 18893611..ae71b78 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1209,6 +1209,13 @@ int mlx5_ib_dereg_mr(struct ib_mr *ibmr)
/* Wait for all running page-fault handlers to finish. */
synchronize_srcu(&dev->mr_srcu);
#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM)
+ if (mlx5_ib_umem_invalidate(umem, ib_umem_start(umem),
+ ib_umem_end(umem), NULL))
+ /*
+ * FIXME do something to kill all mr and umem
+ * in use by this process.
+ */
+ pr_err("killing all mr with odp due to mtt update failure\n");
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */
/* Destroy all page mappings */
mlx5_ib_invalidate_range(umem, ib_umem_start(umem),
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 7299542..5ef31da 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -53,6 +53,180 @@ static struct mlx5_ib_mr *mlx5_ib_odp_find_mr_lkey(struct mlx5_ib_dev *dev,
}

#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM)
+
+int mlx5_ib_umem_invalidate(struct ib_umem *umem, u64 start,
+ u64 end, void *cookie)
+{
+ const u64 umr_block_mask = (MLX5_UMR_MTT_ALIGNMENT / sizeof(u64)) - 1;
+ u64 idx = 0, blk_start_idx = 0;
+ struct hmm_pt_iter iter;
+ struct mlx5_ib_mr *mlx5_ib_mr;
+ struct hmm_mirror *mirror;
+ unsigned long addr;
+ int in_block = 0;
+ int ret = 0;
+
+ if (!umem || !umem->odp_data) {
+ pr_err("invalidation called on NULL umem or non-ODP umem\n");
+ return -EINVAL;
+ }
+
+ /* Is this ib_mr active and registered yet ? */
+ if (umem->odp_data->private == NULL)
+ return 0;
+
+ mlx5_ib_mr = umem->odp_data->private;
+ if (!mlx5_ib_mr->ibmr.pd)
+ return 0;
+
+ mirror = &umem->odp_data->ib_mirror->base;
+ start = max_t(u64, ib_umem_start(umem), start);
+ end = min_t(u64, ib_umem_end(umem), end);
+ hmm_pt_iter_init(&iter, &mirror->pt);
+
+ /*
+ * Iteration one - zap the HW's MTTs. HMM ensures that while we are
+ * doing the invalidation, no page fault will attempt to overwrite the
+ * same MTTs. Concurent invalidations might race us, but they will
+ * write 0s as well, so no difference in the end result.
+ */
+ for (addr = start; addr < end; addr += (u64)umem->page_size) {
+ unsigned long next = end;
+ dma_addr_t *ptep;
+
+ /* Get and lock pointer to mirror page table. */
+ ptep = hmm_pt_iter_walk(&iter, &addr, &next);
+ for (; ptep && addr < next; addr += PAGE_SIZE, ptep++) {
+ idx = (addr - ib_umem_start(umem)) / PAGE_SIZE;
+ /*
+ * Strive to write the MTTs in chunks, but avoid
+ * overwriting non-existing MTTs. The huristic here can
+ * be improved to estimate the cost of another UMR vs.
+ * the cost of bigger UMR.
+ */
+ if ((*ptep) & (ODP_READ_ALLOWED_BIT |
+ ODP_WRITE_ALLOWED_BIT)) {
+ if ((*ptep) & ODP_WRITE_ALLOWED_BIT)
+ hmm_pte_set_dirty(ptep);
+ /*
+ * Because there can not be concurrent overlapping
+ * munmap, page migrate, page write protect then it
+ * is safe here to clear those bits.
+ */
+ hmm_pte_clear_bit(ptep, ODP_READ_ALLOWED_SHIFT);
+ hmm_pte_clear_bit(ptep, ODP_WRITE_ALLOWED_SHIFT);
+ if (!in_block) {
+ blk_start_idx = idx;
+ in_block = 1;
+ }
+ } else {
+ u64 umr_offset = idx & umr_block_mask;
+
+ if (in_block && umr_offset == 0) {
+ ret = mlx5_ib_update_mtt(mlx5_ib_mr,
+ blk_start_idx,
+ idx - blk_start_idx,
+ 1, &iter) || ret;
+ in_block = 0;
+ }
+ }
+ }
+ }
+ if (in_block)
+ ret = mlx5_ib_update_mtt(mlx5_ib_mr, blk_start_idx,
+ idx - blk_start_idx + 1, 1,
+ &iter) || ret;
+ hmm_pt_iter_fini(&iter);
+ return ret;
+}
+
+static int mlx5_hmm_invalidate_range(struct hmm_mirror *mirror,
+ unsigned long start,
+ unsigned long end)
+{
+ struct ib_mirror *ib_mirror;
+ int ret;
+
+ ib_mirror = container_of(mirror, struct ib_mirror, base);
+
+ /* Go over all memory region and invalidate them. */
+ down_read(&ib_mirror->umem_rwsem);
+ ret = rbt_ib_umem_for_each_in_range(&ib_mirror->umem_tree, start, end,
+ mlx5_ib_umem_invalidate, NULL);
+ up_read(&ib_mirror->umem_rwsem);
+ return ret;
+}
+
+static void mlx5_hmm_release(struct hmm_mirror *mirror)
+{
+ struct ib_mirror *ib_mirror;
+
+ ib_mirror = container_of(mirror, struct ib_mirror, base);
+
+ /* Go over all memory region and invalidate them. */
+ mlx5_hmm_invalidate_range(mirror, 0, ULLONG_MAX);
+}
+
+static void mlx5_hmm_free(struct hmm_mirror *mirror)
+{
+ struct ib_mirror *ib_mirror;
+
+ ib_mirror = container_of(mirror, struct ib_mirror, base);
+ kfree(ib_mirror);
+}
+
+static int mlx5_hmm_update(struct hmm_mirror *mirror,
+ struct hmm_event *event)
+{
+ struct device *device = mirror->device->dev;
+ int ret = 0;
+
+ switch (event->etype) {
+ case HMM_DEVICE_RFAULT:
+ case HMM_DEVICE_WFAULT:
+ /* FIXME implement. */
+ break;
+ case HMM_NONE:
+ default:
+ dev_warn(device, "Warning: unhandled HMM event (%d) defaulting to invalidation\n",
+ event->etype);
+ /* Fallthrough. */
+ /* For write protect and fork we could only invalidate writeable mr. */
+ case HMM_WRITE_PROTECT:
+ case HMM_MIGRATE:
+ case HMM_MUNMAP:
+ case HMM_FORK:
+ ret = mlx5_hmm_invalidate_range(mirror,
+ event->start,
+ event->end);
+ break;
+ }
+
+ return ret;
+}
+
+static const struct hmm_device_ops mlx5_hmm_ops = {
+ .release = &mlx5_hmm_release,
+ .free = &mlx5_hmm_free,
+ .update = &mlx5_hmm_update,
+};
+
+void mlx5_dev_init_odp_hmm(struct ib_device *ib_device, struct device *dev)
+{
+ INIT_LIST_HEAD(&ib_device->ib_mirrors);
+ ib_device->hmm_dev.dev = dev;
+ ib_device->hmm_dev.ops = &mlx5_hmm_ops;
+ ib_device->hmm_ready = !hmm_device_register(&ib_device->hmm_dev);
+ mutex_init(&ib_device->hmm_mutex);
+}
+
+void mlx5_dev_fini_odp_hmm(struct ib_device *ib_device)
+{
+ if (!ib_device->hmm_ready)
+ return;
+ hmm_device_unregister(&ib_device->hmm_dev);
+}
+
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */


diff --git a/include/rdma/ib_umem_odp.h b/include/rdma/ib_umem_odp.h
index 36b72f0..fccbf36 100644
--- a/include/rdma/ib_umem_odp.h
+++ b/include/rdma/ib_umem_odp.h
@@ -133,6 +133,23 @@ struct umem_odp_node *rbt_ib_umem_iter_next(struct umem_odp_node *node,


#if IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM)
+
+/*
+ * HMM have few bits reserved for hardware specific bits inside the mirror page
+ * table. For IB we record the mapping protection per page there.
+ */
+#define ODP_READ_ALLOWED_SHIFT (HMM_PTE_HW_SHIFT + 0)
+#define ODP_WRITE_ALLOWED_SHIFT (HMM_PTE_HW_SHIFT + 1)
+#define ODP_READ_ALLOWED_BIT (1 << ODP_READ_ALLOWED_SHIFT)
+#define ODP_WRITE_ALLOWED_BIT (1 << ODP_WRITE_ALLOWED_SHIFT)
+
+/* Make sure we are not overwritting valid address bit on target arch. */
+#if (HMM_PTE_HW_SHIFT + 2) > PAGE_SHIFT
+#error (HMM_PTE_HW_SHIFT + 2) > PAGE_SHIFT
+#endif
+
+#define ODP_DMA_ADDR_MASK HMM_PTE_DMA_MASK
+
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */


--
1.9.3

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