[PATCH 07/44] drm/amdkfd: validate svm range system memory

From: Felix Kuehling <Felix.Kuehling@amd.com>
To: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org
Cc: Philip Yang <Philip.Yang@amd.com>
Subject: [PATCH 07/44] drm/amdkfd: validate svm range system memory
Date: Mon, 22 Mar 2021 06:58:23 -0400	[thread overview]
Message-ID: <20210322105900.14068-8-Felix.Kuehling@amd.com> (raw)
In-Reply-To: <20210322105900.14068-1-Felix.Kuehling@amd.com>

From: Philip Yang <Philip.Yang@amd.com>

Use HMM to get system memory pages address, which will be used to
map to GPUs or migrate to vram.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 103 ++++++++++++++++++++++++++-
 drivers/gpu/drm/amd/amdkfd/kfd_svm.h |   4 ++
 2 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index e57103a9025e..6024caf7373f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -28,6 +28,15 @@
 #include "kfd_priv.h"
 #include "kfd_svm.h"
 
+static bool
+svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
+				    const struct mmu_notifier_range *range,
+				    unsigned long cur_seq);
+
+static const struct mmu_interval_notifier_ops svm_range_mn_ops = {
+	.invalidate = svm_range_cpu_invalidate_pagetables,
+};
+
 /**
  * svm_range_unlink - unlink svm_range from lists and interval tree
  * @prange: svm range structure to be removed
@@ -46,6 +55,18 @@ static void svm_range_unlink(struct svm_range *prange)
 		interval_tree_remove(&prange->it_node, &prange->svms->objects);
 }
 
+static void
+svm_range_add_notifier_locked(struct mm_struct *mm, struct svm_range *prange)
+{
+	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
+		 prange, prange->start, prange->last);
+
+	mmu_interval_notifier_insert_locked(&prange->notifier, mm,
+				     prange->start << PAGE_SHIFT,
+				     prange->npages << PAGE_SHIFT,
+				     &svm_range_mn_ops);
+}
+
 /**
  * svm_range_add_to_svms - add svm range to svms
  * @prange: svm range structure to be added
@@ -65,6 +86,18 @@ static void svm_range_add_to_svms(struct svm_range *prange)
 	interval_tree_insert(&prange->it_node, &prange->svms->objects);
 }
 
+static void svm_range_remove_notifier(struct svm_range *prange)
+{
+	pr_debug("remove notifier svms 0x%p prange 0x%p [0x%lx 0x%lx]\n",
+		 prange->svms, prange,
+		 prange->notifier.interval_tree.start >> PAGE_SHIFT,
+		 prange->notifier.interval_tree.last >> PAGE_SHIFT);
+
+	if (prange->notifier.interval_tree.start != 0 &&
+	    prange->notifier.interval_tree.last != 0)
+		mmu_interval_notifier_remove(&prange->notifier);
+}
+
 static void svm_range_free(struct svm_range *prange)
 {
 	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms, prange,
@@ -112,6 +145,56 @@ svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
 	return prange;
 }
 
+/**
+ * svm_range_validate_ram - get system memory pages of svm range
+ *
+ * @mm: the mm_struct of process
+ * @prange: the range struct
+ *
+ * After mapping system memory to GPU, system memory maybe invalidated anytime
+ * during application running, we use HMM callback to sync GPU with CPU page
+ * table update, so we don't need use lock to prevent CPU invalidation and check
+ * hmm_range_get_pages_done return value.
+ *
+ * Return:
+ * 0 - OK, otherwise error code
+ */
+static int
+svm_range_validate_ram(struct mm_struct *mm, struct svm_range *prange)
+{
+	int r;
+
+	r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL,
+				       prange->start << PAGE_SHIFT,
+				       prange->npages, &prange->hmm_range,
+				       false, true);
+	if (r) {
+		pr_debug("failed %d to get svm range pages\n", r);
+		return r;
+	}
+
+	kvfree(prange->pages_addr);
+	prange->pages_addr = prange->hmm_range->hmm_pfns;
+	prange->hmm_range->hmm_pfns = NULL;
+
+	amdgpu_hmm_range_get_pages_done(prange->hmm_range);
+	prange->hmm_range = NULL;
+
+	return 0;
+}
+
+static int
+svm_range_validate(struct mm_struct *mm, struct svm_range *prange)
+{
+	int r = 0;
+
+	pr_debug("actual loc 0x%x\n", prange->actual_loc);
+
+	r = svm_range_validate_ram(mm, prange);
+
+	return r;
+}
+
 static int
 svm_range_check_attr(struct kfd_process *p,
 		     uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
@@ -581,6 +664,18 @@ svm_range_handle_overlap(struct svm_range_list *svms, struct svm_range *new,
 	return r;
 }
 
+/**
+ * svm_range_cpu_invalidate_pagetables - interval notifier callback
+ *
+ */
+static bool
+svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
+				    const struct mmu_notifier_range *range,
+				    unsigned long cur_seq)
+{
+	return true;
+}
+
 void svm_range_list_fini(struct kfd_process *p)
 {
 	pr_debug("pasid 0x%x svms 0x%p\n", p->pasid, &p->svms);
@@ -732,6 +827,7 @@ svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 	/* Apply changes as a transaction */
 	list_for_each_entry_safe(prange, next, &insert_list, insert_list) {
 		svm_range_add_to_svms(prange);
+		svm_range_add_notifier_locked(mm, prange);
 	}
 	list_for_each_entry(prange, &update_list, update_list) {
 		svm_range_apply_attrs(p, prange, nattr, attrs);
@@ -743,6 +839,7 @@ svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 			 prange->svms, prange, prange->start,
 			 prange->last);
 		svm_range_unlink(prange);
+		svm_range_remove_notifier(prange);
 		svm_range_free(prange);
 	}
 
@@ -753,7 +850,11 @@ svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 	 * case because the rollback wouldn't be guaranteed to work either.
 	 */
 	list_for_each_entry(prange, &update_list, update_list) {
-		/* TODO */
+		r = svm_range_validate(mm, prange);
+		if (r) {
+			pr_debug("failed %d to validate svm range\n", r);
+			break;
+		}
 	}
 
 	svm_range_debug_dump(svms);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
index c46cdad9d1a3..f35a178c607f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
@@ -44,6 +44,7 @@
  * @update_list:link list node used to add to update_list
  * @remove_list:link list node used to add to remove list
  * @insert_list:link list node used to add to insert list
+ * @hmm_range:  hmm range structure used by hmm_range_fault to get system pages
  * @npages:     number of pages
  * @pages_addr: list of system memory physical page address
  * @flags:      flags defined as KFD_IOCTL_SVM_FLAG_*
@@ -51,6 +52,7 @@
  * @perfetch_loc: last prefetch location, 0 for CPU, or GPU id
  * @actual_loc: the actual location, 0 for CPU, or GPU id
  * @granularity:migration granularity, log2 num pages
+ * @notifier:   register mmu interval notifier
  * @bitmap_access: index bitmap of GPUs which can access the range
  * @bitmap_aip: index bitmap of GPUs which can access the range in place
  *
@@ -67,6 +69,7 @@ struct svm_range {
 	struct list_head		update_list;
 	struct list_head		remove_list;
 	struct list_head		insert_list;
+	struct hmm_range		*hmm_range;
 	uint64_t			npages;
 	unsigned long			*pages_addr;
 	uint32_t			flags;
@@ -74,6 +77,7 @@ struct svm_range {
 	uint32_t			prefetch_loc;
 	uint32_t			actual_loc;
 	uint8_t				granularity;
+	struct mmu_interval_notifier	notifier;
 	DECLARE_BITMAP(bitmap_access, MAX_GPU_INSTANCE);
 	DECLARE_BITMAP(bitmap_aip, MAX_GPU_INSTANCE);
 };
-- 
2.31.0

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