From: Nico Boehr <nrb@xxxxxxxxxxxxx> When the SIGP interpretation facility is in use a SIGP external call to a waiting CPU will result in an exit of the calling cpu. For non-pv guests it's a code 56 (partial execution) exit otherwise its a code 108 (secure instruction notification) exit. Those exits are handled differently from a normal SIGP instruction intercept that happens without interpretation and hence need to be tested. Signed-off-by: Nico Boehr <nrb@xxxxxxxxxxxxx> Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220810074616.1223561-4-nrb@xxxxxxxxxxxxx Message-Id: <20220810074616.1223561-4-nrb@xxxxxxxxxxxxx> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx> --- s390x/smp.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) diff --git a/s390x/smp.c b/s390x/smp.c index 5a269087..91f3e3bc 100644 --- a/s390x/smp.c +++ b/s390x/smp.c @@ -356,6 +356,102 @@ static void test_calls(void) } } +static void call_in_wait_ext_int_fixup(struct stack_frame_int *stack) +{ + /* Clear wait bit so we don't immediately wait again after the fixup */ + lowcore.ext_old_psw.mask &= ~PSW_MASK_WAIT; +} + +static void call_in_wait_setup(void) +{ + expect_ext_int(); + ctl_set_bit(0, current_sigp_call_case->cr0_bit); + register_ext_cleanup_func(call_in_wait_ext_int_fixup); + + set_flag(1); +} + +static void call_in_wait_received(void) +{ + report(lowcore.ext_int_code == current_sigp_call_case->ext_int_expected_type, "received"); + + set_flag(1); +} + +static void call_in_wait_cleanup(void) +{ + ctl_clear_bit(0, current_sigp_call_case->cr0_bit); + register_ext_cleanup_func(NULL); + + set_flag(1); +} + +static void test_calls_in_wait(void) +{ + int i; + struct psw psw; + + report_prefix_push("psw wait"); + for (i = 0; i < ARRAY_SIZE(cases_sigp_call); i++) { + current_sigp_call_case = &cases_sigp_call[i]; + + report_prefix_push(current_sigp_call_case->name); + if (!current_sigp_call_case->supports_pv && uv_os_is_guest()) { + report_skip("Not supported under PV"); + report_prefix_pop(); + continue; + } + + /* Let the secondary CPU setup the external mask and the external interrupt cleanup function */ + set_flag(0); + psw.mask = extract_psw_mask(); + psw.addr = (unsigned long)call_in_wait_setup; + smp_cpu_start(1, psw); + + /* Wait until the receiver has finished setup */ + wait_for_flag(); + set_flag(0); + + /* + * To avoid races, we need to know that the secondary CPU has entered wait, + * but the architecture provides no way to check whether the secondary CPU + * is in wait. + * + * But since a waiting CPU is considered operating, simply stop the CPU, set + * up the restart new PSW mask in wait, send the restart interrupt and then + * wait until the CPU becomes operating (done by smp_cpu_start). + */ + smp_cpu_stop(1); + psw.mask = extract_psw_mask() | PSW_MASK_EXT | PSW_MASK_WAIT; + psw.addr = (unsigned long)call_in_wait_received; + smp_cpu_start(1, psw); + + smp_sigp(1, current_sigp_call_case->call, 0, NULL); + + /* Wait until the receiver has handled the call */ + wait_for_flag(); + smp_cpu_stop(1); + set_flag(0); + + /* + * Now clean up the mess we have left behind. If the cleanup + * were part of call_in_wait_received we would not get a chance + * to catch an interrupt that is presented twice since we would + * disable the external call on the first interrupt. + */ + psw.mask = extract_psw_mask(); + psw.addr = (unsigned long)call_in_wait_cleanup; + smp_cpu_start(1, psw); + + /* Wait until the cleanup has been completed */ + wait_for_flag(); + smp_cpu_stop(1); + + report_prefix_pop(); + } + report_prefix_pop(); +} + static void test_sense_running(void) { report_prefix_push("sense_running"); @@ -474,6 +570,7 @@ int main(void) test_store_status(); test_set_prefix(); test_calls(); + test_calls_in_wait(); test_sense_running(); test_reset(); test_reset_initial(); -- 2.34.1
