[kvm-unit-tests PATCH v1 1/2] s390x: skey.c: rework the interrupt handler

[Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>]

The skey test currently uses a cleanup function to work around the
issues that arise when the lowcore is not mapped, since the interrupt
handler needs to access it.

Instead of a cleanup function, simply disable DAT for the interrupt
handler for the tests that remap page 0. This is needed in preparation
of and upcoming patch that will cause the interrupt handler to read
from lowcore before calling the cleanup function.

Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
 s390x/skey.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/s390x/skey.c b/s390x/skey.c
index 32bf1070..d01c6f79 100644
--- a/s390x/skey.c
+++ b/s390x/skey.c
@@ -15,6 +15,7 @@
 #include <asm/facility.h>
 #include <asm/mem.h>
 
+static struct lowcore *lc;
 
 static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
 
@@ -250,19 +251,6 @@ static void set_prefix_key_1(uint32_t *prefix_ptr)
 	);
 }
 
-/*
- * We remapped page 0, making the lowcore inaccessible, which breaks the normal
- * handler and breaks skipping the faulting instruction.
- * Just disable dynamic address translation to make things work.
- */
-static void dat_fixup_pgm_int(void)
-{
-	uint64_t psw_mask = extract_psw_mask();
-
-	psw_mask &= ~PSW_MASK_DAT;
-	load_psw_mask(psw_mask);
-}
-
 #define PREFIX_AREA_SIZE (PAGE_SIZE * 2)
 static char lowcore_tmp[PREFIX_AREA_SIZE] __attribute__((aligned(PREFIX_AREA_SIZE)));
 
@@ -318,7 +306,13 @@ static void test_set_prefix(void)
 	report(get_prefix() == old_prefix, "did not set prefix");
 	report_prefix_pop();
 
-	register_pgm_cleanup_func(dat_fixup_pgm_int);
+	/*
+	 * Page 0 will be remapped, making the lowcore inaccessible, which
+	 * breaks the normal handler and breaks skipping the faulting
+	 * instruction. Disable dynamic address translation for the
+	 * interrupt handler to make things work.
+	 */
+	lc->pgm_new_psw.mask &= ~PSW_MASK_DAT;
 
 	report_prefix_push("remapped page, fetch protection");
 	set_prefix(old_prefix);
@@ -356,7 +350,7 @@ static void test_set_prefix(void)
 	report_prefix_pop();
 
 	ctl_clear_bit(0, CTL0_FETCH_PROTECTION_OVERRIDE);
-	register_pgm_cleanup_func(NULL);
+	lc->pgm_new_psw.mask |= PSW_MASK_DAT;
 	report_prefix_pop();
 	set_storage_key(pagebuf, 0x00, 0);
 	report_prefix_pop();
-- 
2.36.1