[PATCH 19/36] HMM: handle HMM device page table entry on mirror page table fault and update.

[j . glisse]

From: JÃrÃme Glisse <jglisse@xxxxxxxxxx>

When faulting or updating the device page table properly handle the case of device
memory entry.

Signed-off-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
---
 mm/hmm.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/mm/hmm.c b/mm/hmm.c
index 761905a..e4585b7 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -613,6 +613,13 @@ static void hmm_mirror_update_pte(struct hmm_mirror *mirror,
 		goto out;
 	}
 
+	if (hmm_pte_test_valid_dev(hmm_pte)) {
+		*hmm_pte &= event->pte_mask;
+		if (!hmm_pte_test_valid_dev(hmm_pte))
+			hmm_pt_iter_directory_unref(iter, mirror->pt.llevel);
+		return;
+	}
+
 	if (!hmm_pte_test_valid_dma(hmm_pte))
 		return;
 
@@ -813,6 +820,13 @@ static int hmm_mirror_fault_pmd(pmd_t *pmdp,
 		do {
 			next = hmm_pt_level_next(&mirror->pt, addr, hmm_end,
 						 mirror->pt.llevel);
+
+			if (hmm_pte_test_valid_dev(&hmm_pte[i])) {
+				if (write)
+					hmm_pte_set_write(&hmm_pte[i]);
+				continue;
+			}
+
 			if (!pte_present(*ptep) || (write && !pte_write(*ptep))) {
 				ret = -ENOENT;
 				ptep++;
-- 
1.9.3

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