From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-1.mimecast.com ([207.211.31.81]:41663 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726729AbgAWN4f (ORCPT ); Thu, 23 Jan 2020 08:56:35 -0500 Subject: Re: [kvm-unit-tests PATCH v4 2/9] s390x: smp: Only use smp_cpu_setup once References: <20200121134254.4570-1-frankja@linux.ibm.com> <20200121134254.4570-3-frankja@linux.ibm.com> From: David Hildenbrand Message-ID: <9a17ce2d-bfce-0a1f-dfa7-3d798af4d5ab@redhat.com> Date: Thu, 23 Jan 2020 14:56:26 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Janosch Frank , kvm@vger.kernel.org Cc: thuth@redhat.com, borntraeger@de.ibm.com, linux-s390@vger.kernel.org, cohuck@redhat.com On 23.01.20 14:54, Janosch Frank wrote: > On 1/23/20 2:45 PM, David Hildenbrand wrote: >> On 21.01.20 14:42, Janosch Frank wrote: >>> Let's stop and start instead of using setup to run a function on a >>> cpu. >>> >>> Signed-off-by: Janosch Frank >>> Reviewed-by: Thomas Huth >>> Reviewed-by: Cornelia Huck >>> Acked-by: David Hildenbrand >>> --- >>> s390x/smp.c | 21 ++++++++++++++------- >>> 1 file changed, 14 insertions(+), 7 deletions(-) >>> >>> diff --git a/s390x/smp.c b/s390x/smp.c >>> index e37eb56..3e8cf3e 100644 >>> --- a/s390x/smp.c >>> +++ b/s390x/smp.c >>> @@ -53,7 +53,7 @@ static void test_start(void) >>> psw.addr = (unsigned long)test_func; >>> >>> set_flag(0); >>> - smp_cpu_setup(1, psw); >>> + smp_cpu_start(1, psw); >>> wait_for_flag(); >>> report(1, "start"); >>> } >>> @@ -109,6 +109,7 @@ static void test_store_status(void) >>> report(1, "status written"); >>> free_pages(status, PAGE_SIZE * 2); >>> report_prefix_pop(); >>> + smp_cpu_stop(1); >>> >>> report_prefix_pop(); >>> } >>> @@ -137,9 +138,8 @@ static void test_ecall(void) >>> >>> report_prefix_push("ecall"); >>> set_flag(0); >>> - smp_cpu_destroy(1); >>> >>> - smp_cpu_setup(1, psw); >>> + smp_cpu_start(1, psw); >>> wait_for_flag(); >>> set_flag(0); >>> sigp(1, SIGP_EXTERNAL_CALL, 0, NULL); >>> @@ -172,9 +172,8 @@ static void test_emcall(void) >>> >>> report_prefix_push("emcall"); >>> set_flag(0); >>> - smp_cpu_destroy(1); >>> >>> - smp_cpu_setup(1, psw); >>> + smp_cpu_start(1, psw); >>> wait_for_flag(); >>> set_flag(0); >>> sigp(1, SIGP_EMERGENCY_SIGNAL, 0, NULL); >>> @@ -192,7 +191,7 @@ static void test_reset_initial(void) >>> psw.addr = (unsigned long)test_func; >>> >>> report_prefix_push("reset initial"); >>> - smp_cpu_setup(1, psw); >>> + smp_cpu_start(1, psw); >>> >>> sigp_retry(1, SIGP_INITIAL_CPU_RESET, 0, NULL); >>> sigp(1, SIGP_STORE_STATUS_AT_ADDRESS, (uintptr_t)status, NULL); >>> @@ -223,7 +222,7 @@ static void test_reset(void) >>> psw.addr = (unsigned long)test_func; >>> >>> report_prefix_push("cpu reset"); >>> - smp_cpu_setup(1, psw); >>> + smp_cpu_start(1, psw); >>> >>> sigp_retry(1, SIGP_CPU_RESET, 0, NULL); >>> report(smp_cpu_stopped(1), "cpu stopped"); >>> @@ -232,6 +231,7 @@ static void test_reset(void) >>> >>> int main(void) >>> { >>> + struct psw psw; >>> report_prefix_push("smp"); >>> >>> if (smp_query_num_cpus() == 1) { >>> @@ -239,6 +239,12 @@ int main(void) >>> goto done; >>> } >>> >>> + /* Setting up the cpu to give it a stack and lowcore */ >>> + psw.mask = extract_psw_mask(); >>> + psw.addr = (unsigned long)cpu_loop; >>> + smp_cpu_setup(1, psw); >>> + smp_cpu_stop(1); >>> + >>> test_start(); >>> test_stop(); >>> test_stop_store_status(); >>> @@ -247,6 +253,7 @@ int main(void) >>> test_emcall(); >>> test_reset(); >>> test_reset_initial(); >>> + smp_cpu_destroy(1); >>> >>> done: >>> report_prefix_pop(); >>> >> >> With this patch, I get timeouts under TCG. Seems to loop forever. >> > The branch works on lpar and kvm without a problem. Which could mean that either TCG is broken or your test is broken (e.g., a race condition that does not trigger under LPAR because it's faster, or some undocumented/not guaranteed behavior). -- Thanks, David / dhildenb