[PATCH v2 43/46] KVM: selftests: add HugeTLB HGM to KVM demand paging selftest

[James Houghton <jthoughton@google.com>]

This test exercises the GUP paths for HGM. MADV_COLLAPSE is not tested.

Signed-off-by: James Houghton <jthoughton@google.com>

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index b0e1fc4de9e2..e534f9c927bf 100644
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -170,7 +170,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 			uffd_descs[i] = uffd_setup_demand_paging(
 				p->uffd_mode, p->uffd_delay, vcpu_hva,
 				vcpu_args->pages * memstress_args.guest_page_size,
-				&handle_uffd_page_request);
+				p->src_type, &handle_uffd_page_request);
 		}
 	}
 
diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index 80d6416f3012..a2106c19a614 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -103,6 +103,7 @@ enum vm_mem_backing_src_type {
 	VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB,
 	VM_MEM_SRC_SHMEM,
 	VM_MEM_SRC_SHARED_HUGETLB,
+	VM_MEM_SRC_SHARED_HUGETLB_HGM,
 	NUM_SRC_TYPES,
 };
 
@@ -121,6 +122,7 @@ size_t get_def_hugetlb_pagesz(void);
 const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i);
 size_t get_backing_src_pagesz(uint32_t i);
 bool is_backing_src_hugetlb(uint32_t i);
+bool is_backing_src_shared_hugetlb(enum vm_mem_backing_src_type src_type);
 void backing_src_help(const char *flag);
 enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name);
 long get_run_delay(void);
diff --git a/tools/testing/selftests/kvm/include/userfaultfd_util.h b/tools/testing/selftests/kvm/include/userfaultfd_util.h
index 877449c34592..d91528a58245 100644
--- a/tools/testing/selftests/kvm/include/userfaultfd_util.h
+++ b/tools/testing/selftests/kvm/include/userfaultfd_util.h
@@ -26,9 +26,9 @@ struct uffd_desc {
 	pthread_t thread;
 };
 
-struct uffd_desc *uffd_setup_demand_paging(int uffd_mode, useconds_t delay,
-					   void *hva, uint64_t len,
-					   uffd_handler_t handler);
+struct uffd_desc *uffd_setup_demand_paging(
+		int uffd_mode, useconds_t delay, void *hva, uint64_t len,
+		enum vm_mem_backing_src_type src_type, uffd_handler_t handler);
 
 void uffd_stop_demand_paging(struct uffd_desc *uffd);
 
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 56d5ea949cbb..b9c398dc295d 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -981,7 +981,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 	region->fd = -1;
 	if (backing_src_is_shared(src_type))
 		region->fd = kvm_memfd_alloc(region->mmap_size,
-					     src_type == VM_MEM_SRC_SHARED_HUGETLB);
+				is_backing_src_shared_hugetlb(src_type));
 
 	region->mmap_start = mmap(NULL, region->mmap_size,
 				  PROT_READ | PROT_WRITE,
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index 5c22fa4c2825..712a0878932e 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -271,6 +271,13 @@ const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i)
 			 */
 			.flag = MAP_SHARED,
 		},
+		[VM_MEM_SRC_SHARED_HUGETLB_HGM] = {
+			/*
+			 * Identical to shared_hugetlb except for the name.
+			 */
+			.name = "shared_hugetlb_hgm",
+			.flag = MAP_SHARED,
+		},
 	};
 	_Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES,
 		       "Missing new backing src types?");
@@ -289,6 +296,7 @@ size_t get_backing_src_pagesz(uint32_t i)
 	switch (i) {
 	case VM_MEM_SRC_ANONYMOUS:
 	case VM_MEM_SRC_SHMEM:
+	case VM_MEM_SRC_SHARED_HUGETLB_HGM:
 		return getpagesize();
 	case VM_MEM_SRC_ANONYMOUS_THP:
 		return get_trans_hugepagesz();
@@ -305,6 +313,12 @@ bool is_backing_src_hugetlb(uint32_t i)
 	return !!(vm_mem_backing_src_alias(i)->flag & MAP_HUGETLB);
 }
 
+bool is_backing_src_shared_hugetlb(enum vm_mem_backing_src_type src_type)
+{
+	return src_type == VM_MEM_SRC_SHARED_HUGETLB ||
+		src_type == VM_MEM_SRC_SHARED_HUGETLB_HGM;
+}
+
 static void print_available_backing_src_types(const char *prefix)
 {
 	int i;
diff --git a/tools/testing/selftests/kvm/lib/userfaultfd_util.c b/tools/testing/selftests/kvm/lib/userfaultfd_util.c
index 92cef20902f1..3c7178d6c4f4 100644
--- a/tools/testing/selftests/kvm/lib/userfaultfd_util.c
+++ b/tools/testing/selftests/kvm/lib/userfaultfd_util.c
@@ -25,6 +25,10 @@
 
 #ifdef __NR_userfaultfd
 
+#ifndef MADV_SPLIT
+#define MADV_SPLIT 26
+#endif
+
 static void *uffd_handler_thread_fn(void *arg)
 {
 	struct uffd_desc *uffd_desc = (struct uffd_desc *)arg;
@@ -108,9 +112,9 @@ static void *uffd_handler_thread_fn(void *arg)
 	return NULL;
 }
 
-struct uffd_desc *uffd_setup_demand_paging(int uffd_mode, useconds_t delay,
-					   void *hva, uint64_t len,
-					   uffd_handler_t handler)
+struct uffd_desc *uffd_setup_demand_paging(
+		int uffd_mode, useconds_t delay, void *hva, uint64_t len,
+		enum vm_mem_backing_src_type src_type, uffd_handler_t handler)
 {
 	struct uffd_desc *uffd_desc;
 	bool is_minor = (uffd_mode == UFFDIO_REGISTER_MODE_MINOR);
@@ -140,6 +144,10 @@ struct uffd_desc *uffd_setup_demand_paging(int uffd_mode, useconds_t delay,
 		    "ioctl UFFDIO_API failed: %" PRIu64,
 		    (uint64_t)uffdio_api.api);
 
+	if (src_type == VM_MEM_SRC_SHARED_HUGETLB_HGM)
+		TEST_ASSERT(!madvise(hva, len, MADV_SPLIT),
+				"Could not enable HGM");
+
 	uffdio_register.range.start = (uint64_t)hva;
 	uffdio_register.range.len = len;
 	uffdio_register.mode = uffd_mode;
-- 
2.39.2.637.g21b0678d19-goog