drm/amdgpu: add common HMM get pages function

Move the HMM get pages function from amdgpu_ttm and to amdgpu_mn. This
common function will be used by new svm APIs.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
index 828b5167ff12..997da4237a10 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
@@ -155,3 +155,86 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
 	mmu_interval_notifier_remove(&bo->notifier);
 	bo->notifier.mm = NULL;
 }
+
+int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
+			       struct mm_struct *mm, struct page **pages,
+			       uint64_t start, uint64_t npages,
+			       struct hmm_range **phmm_range, bool readonly,
+			       bool mmap_locked)
+{
+	struct hmm_range *hmm_range;
+	unsigned long timeout;
+	unsigned long i;
+	unsigned long *pfns;
+	int r = 0;
+
+	hmm_range = kzalloc(sizeof(*hmm_range), GFP_KERNEL);
+	if (unlikely(!hmm_range))
+		return -ENOMEM;
+
+	pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL);
+	if (unlikely(!pfns)) {
+		r = -ENOMEM;
+		goto out_free_range;
+	}
+
+	hmm_range->notifier = notifier;
+	hmm_range->default_flags = HMM_PFN_REQ_FAULT;
+	if (!readonly)
+		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
+	hmm_range->hmm_pfns = pfns;
+	hmm_range->start = start;
+	hmm_range->end = start + npages * PAGE_SIZE;
+	timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+
+retry:
+	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
+
+	if (likely(!mmap_locked))
+		mmap_read_lock(mm);
+
+	r = hmm_range_fault(hmm_range);
+
+	if (likely(!mmap_locked))
+		mmap_read_unlock(mm);
+	if (unlikely(r)) {
+		/*
+		 * FIXME: This timeout should encompass the retry from
+		 * mmu_interval_read_retry() as well.
+		 */
+		if (r == -EBUSY && !time_after(jiffies, timeout))
+			goto retry;
+		goto out_free_pfns;
+	}
+
+	/*
+	 * Due to default_flags, all pages are HMM_PFN_VALID or
+	 * hmm_range_fault() fails. FIXME: The pages cannot be touched outside
+	 * the notifier_lock, and mmu_interval_read_retry() must be done first.
+	 */
+	for (i = 0; pages && i < npages; i++)
+		pages[i] = hmm_pfn_to_page(pfns[i]);
+
+	*phmm_range = hmm_range;
+
+	return 0;
+
+out_free_pfns:
+	kvfree(pfns);
+out_free_range:
+	kfree(hmm_range);
+
+	return r;
+}
+
+int amdgpu_hmm_range_get_pages_done(struct hmm_range *hmm_range)
+{
+	int r;
+
+	r = mmu_interval_read_retry(hmm_range->notifier,
+				    hmm_range->notifier_seq);
+	kvfree(hmm_range->hmm_pfns);
+	kfree(hmm_range);
+
+	return r;
+}