[kvm-unit-tests PATCH] s390x/intercept: Test invalid prefix argument to SET PREFIX

[Janis Schoetterl-Glausch <scgl@linux.ibm.com>]

According to the architecture, SET PREFIX must try to access the new
prefix area and recognize an addressing exception if the area is not
accessible.
Test that the exception occurs when we try to set a prefix higher
than the available memory.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
 s390x/intercept.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/s390x/intercept.c b/s390x/intercept.c
index 86e57e11..0b90e588 100644
--- a/s390x/intercept.c
+++ b/s390x/intercept.c
@@ -74,6 +74,20 @@ static void test_spx(void)
 	expect_pgm_int();
 	asm volatile(" spx 0(%0) " : : "r"(-8L));
 	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
+
+	new_prefix = get_ram_size() & 0x7fffe000;
+	if (get_ram_size() - new_prefix < 2 * PAGE_SIZE) {
+		expect_pgm_int();
+		asm volatile("spx	%0 " : : "Q"(new_prefix));
+		check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
+
+		/*
+		 * Cannot test inaccessibility of the second page the same way.
+		 * If we try to use the last page as first half of the prefix
+		 * area and our ram size is a multiple of 8k, after SPX aligns
+		 * the address to 8k we have a completely accessible area.
+		 */
+	}
 }
 
 /* Test the STORE CPU ADDRESS instruction */

base-commit: 110c69492b53f0070e1bbce986fb635e72a423b4
-- 
2.36.1