From a3aa96af197942ce2c6dc043d29c3fd27575a765 Mon Sep 17 00:00:00 2001
From: Balazs Gerofi <bgerofi@riken.jp>
Date: Wed, 25 Apr 2018 16:15:26 +0900
Subject: [PATCH] MM: introduction of ihk_mc_pt_lookup_fault_pte()

---
 arch/x86_64/kernel/memory.c | 24 +++++++++++++++++++++++-
 lib/include/ihk/mm.h        |  5 ++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86_64/kernel/memory.c b/arch/x86_64/kernel/memory.c
index 2835463a..d23d15c1 100644
--- a/arch/x86_64/kernel/memory.c
+++ b/arch/x86_64/kernel/memory.c
@@ -1987,6 +1987,28 @@ out:
 	return ptep;
 }
 
+pte_t *ihk_mc_pt_lookup_fault_pte(struct process_vm *vm, void *virt,
+		int pgshift, void **basep, size_t *sizep, int *p2alignp)
+{
+	int faulted = 0;
+	pte_t *ptep;
+
+retry:
+	ptep = ihk_mc_pt_lookup_pte(vm->address_space->page_table,
+			virt, pgshift, basep, sizep, p2alignp);
+	if (!faulted && (!ptep || !pte_is_present(ptep))) {
+		page_fault_process_vm(vm, virt, PF_POPULATE | PF_USER);
+		faulted = 1;
+		goto retry;
+	}
+
+	if (faulted && ptep && pte_is_present(ptep)) {
+		kprintf("%s: successfully faulted 0x%lx\n", __FUNCTION__, virt);
+	}
+
+	return ptep;
+}
+
 pte_t *ihk_mc_pt_lookup_pte(page_table_t pt, void *virt, int pgshift,
 		void **basep, size_t *sizep, int *p2alignp)
 {
@@ -2286,7 +2308,7 @@ out:
 
 int ihk_mc_pt_set_range(page_table_t pt, struct process_vm *vm, void *start, 
 		void *end, uintptr_t phys, enum ihk_mc_pt_attribute attr,
-						int pgshift, struct vm_range *range)
+		int pgshift, struct vm_range *range)
 {
 	int error;
 	struct set_range_args args;
diff --git a/lib/include/ihk/mm.h b/lib/include/ihk/mm.h
index 3053de49..e380b2c4 100644
--- a/lib/include/ihk/mm.h
+++ b/lib/include/ihk/mm.h
@@ -176,7 +176,10 @@ int ihk_mc_pt_free_range(page_table_t pt, struct process_vm *vm,
 int ihk_mc_pt_change_attr_range(page_table_t pt, void *start, void *end,
 		enum ihk_mc_pt_attribute clrattr,
 		enum ihk_mc_pt_attribute setattr);
-pte_t *ihk_mc_pt_lookup_pte(page_table_t pt, void *virt, int pgshift, void **pgbasep, size_t *pgsizep, int *p2alignp);
+pte_t *ihk_mc_pt_lookup_pte(page_table_t pt, void *virt, int pgshift,
+		void **pgbasep, size_t *pgsizep, int *p2alignp);
+pte_t *ihk_mc_pt_lookup_fault_pte(struct process_vm *vm, void *virt,
+		int pgshift, void **basep, size_t *sizep, int *p2alignp);
 int ihk_mc_pt_set_range(page_table_t pt, struct process_vm *vm, void *start, 
 		void *end, uintptr_t phys, enum ihk_mc_pt_attribute attr,
 						int pgshift, struct vm_range *range);