[kvm-unit-tests PATCH v5 2/6] s390x: add function to set DAT mode for all interrupts

Nico Boehr
2023-07-12T11:42:31Z

When toggling DAT or switch address space modes, it is likely that
interrupts should be handled in the same DAT or address space mode.

Add a function which toggles DAT and address space mode for all
interruptions, except restart interrupts.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
lib/s390x/asm/interrupt.h | 4 ++++
lib/s390x/interrupt.c | 36 ++++++++++++++++++++++++++++++++++++
lib/s390x/mmu.c | 5 +++--
3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/lib/s390x/asm/interrupt.h b/lib/s390x/asm/interrupt.h
index 35c1145f0349..55759002dce2 100644
--- a/lib/s390x/asm/interrupt.h
+++ b/lib/s390x/asm/interrupt.h
@@ -83,6 +83,10 @@ void expect_ext_int(void);
uint16_t clear_pgm_int(void);
void check_pgm_int_code(uint16_t code);

+#define IRQ_DAT_ON true
+#define IRQ_DAT_OFF false
+void irq_set_dat_mode(bool dat, uint64_t as);
+
/* Activate low-address protection */
static inline void low_prot_enable(void)
{
diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 3f993a363ae2..9b1bc6ce819d 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -9,6 +9,7 @@
*/
#include <libcflat.h>
#include <asm/barrier.h>
+#include <asm/mem.h>
#include <asm/asm-offsets.h>
#include <sclp.h>
#include <interrupt.h>
@@ -104,6 +105,41 @@ void register_ext_cleanup_func(void (*f)(struct stack_frame_int *))
THIS_CPU->ext_cleanup_func = f;
}

+/**
+ * irq_set_dat_mode - Set the DAT mode of all interrupt handlers, except for
+ * restart.
+ * This will update the DAT mode and address space mode of all interrupt new
+ * PSWs.
+ *
+ * Since enabling DAT needs initalized CRs and the restart new PSW is often used
+ * to initalize CRs, the restart new PSW is never touched to avoid the chicken
+ * and egg situation.
+ *
+ * @dat specifies whether to use DAT or not
+ * @as specifies the address space mode to use - one of AS_PRIM, AS_ACCR,
+ * AS_SECN or AS_HOME.
+ */
+void irq_set_dat_mode(bool dat, uint64_t as)
+{
+ struct psw* irq_psws[] = {
+ OPAQUE_PTR(GEN_LC_EXT_NEW_PSW),
+ OPAQUE_PTR(GEN_LC_SVC_NEW_PSW),
+ OPAQUE_PTR(GEN_LC_PGM_NEW_PSW),
+ OPAQUE_PTR(GEN_LC_MCCK_NEW_PSW),
+ OPAQUE_PTR(GEN_LC_IO_NEW_PSW),
+ };
+ struct psw *psw;
+
+ assert(as == AS_PRIM || as == AS_ACCR || as == AS_SECN || as == AS_HOME);
+
+ for (size_t i = 0; i < ARRAY_SIZE(irq_psws); i++) {
+ psw = irq_psws[i];
+ psw->dat = dat;
+ if (dat)
+ psw->as = as;
+ }
+}
+
static void fixup_pgm_int(struct stack_frame_int *stack)
{
/* If we have an error on SIE we directly move to sie_exit */
diff --git a/lib/s390x/mmu.c b/lib/s390x/mmu.c
index b474d7021d3f..199bd3fbc9c8 100644
--- a/lib/s390x/mmu.c
+++ b/lib/s390x/mmu.c
@@ -12,6 +12,7 @@
#include <asm/pgtable.h>
#include <asm/arch_def.h>
#include <asm/barrier.h>
+#include <asm/interrupt.h>
#include <vmalloc.h>
#include "mmu.h"

@@ -41,8 +42,8 @@ static void mmu_enable(pgd_t *pgtable)
/* enable dat (primary == 0 set as default) */
enable_dat();

- /* we can now also use DAT unconditionally in our PGM handler */
- lowcore.pgm_new_psw.mask |= PSW_MASK_DAT;
+ /* we can now also use DAT in all interrupt handlers */
+ irq_set_dat_mode(IRQ_DAT_ON, AS_PRIM);
}

/*
--
2.40.1