[kvm-unit-tests PATCH v1 2/2] lib: s390x: better smp interrupt checks

Claudio Imbrenda
2022-06-03T15:40:48Z

Use per-CPU flags and callbacks for Program, Extern, and I/O interrupts
instead of global variables.

This allows for more accurate error handling; a CPU waiting for an
interrupt will not have it "stolen" by a different CPU that was not
supposed to wait for one, and now two CPUs can wait for interrupts at
the same time.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
lib/s390x/asm/arch_def.h | 7 ++++++-
lib/s390x/interrupt.c | 38 ++++++++++++++++----------------------
2 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 72553819..3a0d9c43 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -124,7 +124,12 @@ struct lowcore {
uint8_t pad_0x0280[0x0308 - 0x0280]; /* 0x0280 */
uint64_t sw_int_crs[16]; /* 0x0308 */
struct psw sw_int_psw; /* 0x0388 */
- uint8_t pad_0x0310[0x11b0 - 0x0398]; /* 0x0398 */
+ uint32_t pgm_int_expected; /* 0x0398 */
+ uint32_t ext_int_expected; /* 0x039c */
+ void (*pgm_cleanup_func)(void); /* 0x03a0 */
+ void (*ext_cleanup_func)(void); /* 0x03a8 */
+ void (*io_int_func)(void); /* 0x03b0 */
+ uint8_t pad_0x03b8[0x11b0 - 0x03b8]; /* 0x03b8 */
uint64_t mcck_ext_sa_addr; /* 0x11b0 */
uint8_t pad_0x11b8[0x1200 - 0x11b8]; /* 0x11b8 */
uint64_t fprs_sa[16]; /* 0x1200 */
diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 27d3b767..e57946f0 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -15,14 +15,11 @@
#include <fault.h>
#include <asm/page.h>

-static bool pgm_int_expected;
-static bool ext_int_expected;
-static void (*pgm_cleanup_func)(void);
static struct lowcore *lc;

void expect_pgm_int(void)
{
- pgm_int_expected = true;
+ lc->pgm_int_expected = 1;
lc->pgm_int_code = 0;
lc->trans_exc_id = 0;
mb();
@@ -30,7 +27,7 @@ void expect_pgm_int(void)

void expect_ext_int(void)
{
- ext_int_expected = true;
+ lc->ext_int_expected = 1;
lc->ext_int_code = 0;
mb();
}
@@ -43,7 +40,7 @@ uint16_t clear_pgm_int(void)
code = lc->pgm_int_code;
lc->pgm_int_code = 0;
lc->trans_exc_id = 0;
- pgm_int_expected = false;
+ lc->pgm_int_expected = 0;
return code;
}

@@ -57,7 +54,7 @@ void check_pgm_int_code(uint16_t code)

void register_pgm_cleanup_func(void (*f)(void))
{
- pgm_cleanup_func = f;
+ lc->pgm_cleanup_func = f;
}

static void fixup_pgm_int(struct stack_frame_int *stack)
@@ -184,24 +181,23 @@ static void print_pgm_info(struct stack_frame_int *stack)

void handle_pgm_int(struct stack_frame_int *stack)
{
- if (!pgm_int_expected) {
+ if (!lc->pgm_int_expected) {
/* Force sclp_busy to false, otherwise we will loop forever */
sclp_handle_ext();
print_pgm_info(stack);
}

- pgm_int_expected = false;
+ lc->pgm_int_expected = 0;

- if (pgm_cleanup_func)
- (*pgm_cleanup_func)();
+ if (lc->pgm_cleanup_func)
+ (*lc->pgm_cleanup_func)();
else
fixup_pgm_int(stack);
}

void handle_ext_int(struct stack_frame_int *stack)
{
- if (!ext_int_expected &&
- lc->ext_int_code != EXT_IRQ_SERVICE_SIG) {
+ if (!lc->ext_int_expected && lc->ext_int_code != EXT_IRQ_SERVICE_SIG) {
report_abort("Unexpected external call interrupt (code %#x): on cpu %d at %#lx",
lc->ext_int_code, stap(), lc->ext_old_psw.addr);
return;
@@ -211,7 +207,7 @@ void handle_ext_int(struct stack_frame_int *stack)
stack->crs[0] &= ~(1UL << 9);
sclp_handle_ext();
} else {
- ext_int_expected = false;
+ lc->ext_int_expected = 0;
}

if (!(stack->crs[0] & CR0_EXTM_MASK))
@@ -224,12 +220,10 @@ void handle_mcck_int(void)
stap(), lc->mcck_old_psw.addr);
}

-static void (*io_int_func)(void);
-
void handle_io_int(void)
{
- if (io_int_func)
- return io_int_func();
+ if (lc->io_int_func)
+ return lc->io_int_func();

report_abort("Unexpected io interrupt: on cpu %d at %#lx",
stap(), lc->io_old_psw.addr);
@@ -237,17 +231,17 @@ void handle_io_int(void)

int register_io_int_func(void (*f)(void))
{
- if (io_int_func)
+ if (lc->io_int_func)
return -1;
- io_int_func = f;
+ lc->io_int_func = f;
return 0;
}

int unregister_io_int_func(void (*f)(void))
{
- if (io_int_func != f)
+ if (lc->io_int_func != f)
return -1;
- io_int_func = NULL;
+ lc->io_int_func = NULL;
return 0;
}

--
2.36.1