Expand run_guest_do_rmw() to support checking that data at given pgoff is
not equal to expected_val. This will be used in a later patch that tests
that memory contents are scrambled.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/guest_memfd_conversions_test.c        | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
index c0abc69f15332..277b122ec294c 100644
--- a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
@@ -137,6 +137,7 @@ static void __gmem_conversions_multipage_##test(test_data_t *t, int nr_pages,	\
 struct guest_check_data {
 	void *mem;
 	char expected_val;
+	bool assert_not_equal;
 	char write_val;
 };
 static struct guest_check_data guest_data;
@@ -146,7 +147,13 @@ static void guest_do_rmw(void)
 	for (;;) {
 		char *mem = READ_ONCE(guest_data.mem);
 
-		GUEST_ASSERT_EQ(READ_ONCE(*mem), READ_ONCE(guest_data.expected_val));
+		if (READ_ONCE(guest_data.assert_not_equal)) {
+			GUEST_ASSERT_NE(READ_ONCE(*mem),
+					READ_ONCE(guest_data.expected_val));
+		} else {
+			GUEST_ASSERT_EQ(READ_ONCE(*mem),
+					READ_ONCE(guest_data.expected_val));
+		}
 		WRITE_ONCE(*mem, READ_ONCE(guest_data.write_val));
 
 		GUEST_SYNC(0);
@@ -154,13 +161,15 @@ static void guest_do_rmw(void)
 }
 
 static void run_guest_do_rmw(struct kvm_vcpu *vcpu, loff_t pgoff,
-			     char expected_val, char write_val)
+			     char expected_val, char write_val,
+			     bool assert_not_equal)
 {
 	struct ucall uc;
 	int r;
 
 	guest_data.mem = (void *)GUEST_MEMFD_SHARING_TEST_GVA + pgoff * page_size;
 	guest_data.expected_val = expected_val;
+	guest_data.assert_not_equal = assert_not_equal;
 	guest_data.write_val = write_val;
 	sync_global_to_guest(vcpu->vm, guest_data);
 
@@ -191,7 +200,7 @@ static void test_private(test_data_t *t, loff_t pgoff, char starting_val,
 			 char write_val)
 {
 	TEST_EXPECT_SIGBUS(WRITE_ONCE(t->mem[pgoff * page_size], write_val));
-	run_guest_do_rmw(t->vcpu, pgoff, starting_val, write_val);
+	run_guest_do_rmw(t->vcpu, pgoff, starting_val, write_val, false);
 	TEST_EXPECT_SIGBUS(READ_ONCE(t->mem[pgoff * page_size]));
 }
 
@@ -207,7 +216,7 @@ static void test_shared(test_data_t *t, loff_t pgoff, char starting_val,
 			char host_write_val, char write_val)
 {
 	host_do_rmw(t->mem, pgoff, starting_val, host_write_val);
-	run_guest_do_rmw(t->vcpu, pgoff, host_write_val, write_val);
+	run_guest_do_rmw(t->vcpu, pgoff, host_write_val, write_val, false);
 	TEST_ASSERT_EQ(READ_ONCE(t->mem[pgoff * page_size]), write_val);
 }
 

-- 
2.53.0.1018.g2bb0e51243-goog