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From: Eric Farman <farman@linux.ibm.com>
To: Thomas Huth <thuth@redhat.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>,
	kvm@vger.kernel.org, linux-s390@vger.kernel.org,
	Eric Farman <farman@linux.ibm.com>
Subject: [PATCH kvm-unit-tests v1 6/6] lib: s390x: smp: Convert remaining smp_sigp to _retry
Date: Thu,  3 Mar 2022 22:04:25 +0100	[thread overview]
Message-ID: <20220303210425.1693486-7-farman@linux.ibm.com> (raw)
In-Reply-To: <20220303210425.1693486-1-farman@linux.ibm.com>

A SIGP SENSE is used to determine if a CPU is stopped or operating,
and thus has a vested interest in ensuring it received a CC0 or CC1,
instead of a CC2 (BUSY). But, any order could receive a CC2 response,
and is probably ill-equipped to respond to it.

In practice, the order is likely to only encounter this when racing
with a SIGP STOP (AND STORE STATUS) or SIGP RESTART order, which are
unlikely. But, since it's not impossible, let's convert the library
calls that issue a SIGP to loop on CC2 so the callers do not need
to react to that possible outcome.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 lib/s390x/smp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
index 85b046a5..2e476264 100644
--- a/lib/s390x/smp.c
+++ b/lib/s390x/smp.c
@@ -85,7 +85,7 @@ bool smp_cpu_stopped(uint16_t idx)
 
 bool smp_sense_running_status(uint16_t idx)
 {
-	if (smp_sigp(idx, SIGP_SENSE_RUNNING, 0, NULL) != SIGP_CC_STATUS_STORED)
+	if (smp_sigp_retry(idx, SIGP_SENSE_RUNNING, 0, NULL) != SIGP_CC_STATUS_STORED)
 		return true;
 	/* Status stored condition code is equivalent to cpu not running. */
 	return false;
@@ -169,7 +169,7 @@ static int smp_cpu_restart_nolock(uint16_t idx, struct psw *psw)
 	 * running after the restart.
 	 */
 	smp_cpu_stop_nolock(idx, false);
-	rc = smp_sigp(idx, SIGP_RESTART, 0, NULL);
+	rc = smp_sigp_retry(idx, SIGP_RESTART, 0, NULL);
 	if (rc)
 		return rc;
 	/*
-- 
2.32.0


  parent reply	other threads:[~2022-03-03 21:04 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-03 21:04 [PATCH kvm-unit-tests v1 0/6] s390x: SIGP fixes Eric Farman
2022-03-03 21:04 ` [PATCH kvm-unit-tests v1 1/6] lib: s390x: smp: Retry SIGP SENSE on CC2 Eric Farman
2022-03-07 11:50   ` Nico Boehr
2022-03-07 15:20   ` Claudio Imbrenda
2022-03-03 21:04 ` [PATCH kvm-unit-tests v1 2/6] s390x: smp: Test SIGP RESTART against stopped CPU Eric Farman
2022-03-04 10:43   ` Janosch Frank
2022-03-04 14:20     ` Eric Farman
2022-03-07 12:42   ` Nico Boehr
2022-03-07 15:22   ` Claudio Imbrenda
2022-03-03 21:04 ` [PATCH kvm-unit-tests v1 3/6] s390x: smp: Fix checks for SIGP STOP STORE STATUS Eric Farman
2022-03-04 10:40   ` Janosch Frank
2022-03-04 14:38     ` Eric Farman
2022-03-07 18:30       ` Eric Farman
2022-03-03 21:04 ` [PATCH kvm-unit-tests v1 4/6] s390x: smp: Create and use a non-waiting CPU stop Eric Farman
2022-03-07 13:31   ` Nico Boehr
2022-03-07 19:01     ` Eric Farman
2022-03-07 15:30   ` Claudio Imbrenda
2022-03-07 19:03     ` Eric Farman
2022-03-08 10:31       ` Claudio Imbrenda
2022-03-08 21:18         ` Eric Farman
2022-03-09  9:27           ` Claudio Imbrenda
2022-03-03 21:04 ` [PATCH kvm-unit-tests v1 5/6] s390x: smp: Create and use a non-waiting CPU restart Eric Farman
2022-03-07 15:31   ` Claudio Imbrenda
2022-03-03 21:04 ` Eric Farman [this message]
2022-03-04 10:56   ` [PATCH kvm-unit-tests v1 6/6] lib: s390x: smp: Convert remaining smp_sigp to _retry Janosch Frank
2022-03-04 14:15     ` Eric Farman
2022-03-07 14:42     ` Nico Boehr
2022-03-07 20:15       ` Eric Farman
2022-03-08  9:03         ` Janosch Frank

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