diff mbox series

[kvm-unit-tests,v2,1/6] lib: s390x: smp: Retry SIGP SENSE on CC2

Message ID 20220311173822.1234617-2-farman@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series s390x SIGP fixes | expand

Commit Message

Eric Farman March 11, 2022, 5:38 p.m. UTC
The routine smp_cpu_stopped() issues a SIGP SENSE, and returns true
if it received a CC1 (STATUS STORED) with the STOPPED or CHECK STOP
bits enabled. Otherwise, it returns false.

This is misleading, because a CC2 (BUSY) merely indicates that the
order code could not be processed, not that the CPU is operating.
It could be operating but in the process of being stopped.

Convert the invocation of the SIGP SENSE to retry when a CC2 is
received, so we get a more definitive answer.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 lib/s390x/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Thomas Huth March 24, 2022, 8:08 a.m. UTC | #1
On 11/03/2022 18.38, Eric Farman wrote:
> The routine smp_cpu_stopped() issues a SIGP SENSE, and returns true
> if it received a CC1 (STATUS STORED) with the STOPPED or CHECK STOP
> bits enabled. Otherwise, it returns false.
> 
> This is misleading, because a CC2 (BUSY) merely indicates that the
> order code could not be processed, not that the CPU is operating.
> It could be operating but in the process of being stopped.
> 
> Convert the invocation of the SIGP SENSE to retry when a CC2 is
> received, so we get a more definitive answer.
> 
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   lib/s390x/smp.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
> index 46e1b022..368d6add 100644
> --- a/lib/s390x/smp.c
> +++ b/lib/s390x/smp.c
> @@ -78,7 +78,7 @@ bool smp_cpu_stopped(uint16_t idx)
>   {
>   	uint32_t status;
>   
> -	if (smp_sigp(idx, SIGP_SENSE, 0, &status) != SIGP_CC_STATUS_STORED)
> +	if (smp_sigp_retry(idx, SIGP_SENSE, 0, &status) != SIGP_CC_STATUS_STORED)
>   		return false;
>   	return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
>   }

Reviewed-by: Thomas Huth <thuth@redhat.com>
diff mbox series

Patch

diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
index 46e1b022..368d6add 100644
--- a/lib/s390x/smp.c
+++ b/lib/s390x/smp.c
@@ -78,7 +78,7 @@  bool smp_cpu_stopped(uint16_t idx)
 {
 	uint32_t status;
 
-	if (smp_sigp(idx, SIGP_SENSE, 0, &status) != SIGP_CC_STATUS_STORED)
+	if (smp_sigp_retry(idx, SIGP_SENSE, 0, &status) != SIGP_CC_STATUS_STORED)
 		return false;
 	return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 }