Re: [PATCH v3 3/9] pc-bios: s390x: Move sleep and yield to helper.h

[Janosch Frank <frankja@linux.ibm.com>]

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On 5/27/20 10:34 AM, Christian Borntraeger wrote:
> 
> 
> On 27.05.20 09:49, Janosch Frank wrote:
>> They are definitely helper functions.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  pc-bios/s390-ccw/helper.h      | 17 +++++++++++++++++
>>  pc-bios/s390-ccw/s390-ccw.h    | 16 ----------------
>>  pc-bios/s390-ccw/virtio-net.c  |  1 +
>>  pc-bios/s390-ccw/virtio-scsi.c |  1 +
>>  4 files changed, 19 insertions(+), 16 deletions(-)
>>
>> diff --git a/pc-bios/s390-ccw/helper.h b/pc-bios/s390-ccw/helper.h
>> index 78d5bc7442..d1b8b14d30 100644
>> --- a/pc-bios/s390-ccw/helper.h
>> +++ b/pc-bios/s390-ccw/helper.h
>> @@ -14,6 +14,7 @@
>>  #define S390_CCW_HELPER_H
>>  
>>  #include "s390-ccw.h"
>> +#include "time.h"
>>  
>>  /* Avoids compiler warnings when casting a pointer to a u32 */
>>  static inline uint32_t ptr2u32(void *ptr)
>> @@ -28,4 +29,20 @@ static inline void *u32toptr(uint32_t n)
>>      return (void *)(uint64_t)n;
>>  }
>>  
>> +static inline void yield(void)
>> +{
>> +    asm volatile ("diag 0,0,0x44"
>> +                  : :
>> +                  : "memory", "cc");
>> +}
>> +
>> +static inline void sleep(unsigned int seconds)
>> +{
>> +    ulong target = get_time_seconds() + seconds;
>> +
>> +    while (get_time_seconds() < target) {
>> +        yield();
>> +    }
> 
> This actually asks for a future cleanup patch to replace the busy wait with a sleeping wait.

Yes, already on my list, same as Pierre's busy wait in the kvm unit tests.
One impossible thing at a time.

> 
> Anyway,
> 
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

Thanks!

> 
>> +}
>> +
>>  #endif
>> diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
>> index 9514b76596..c5820e43ae 100644
>> --- a/pc-bios/s390-ccw/s390-ccw.h
>> +++ b/pc-bios/s390-ccw/s390-ccw.h
>> @@ -142,24 +142,8 @@ static inline void debug_print_addr(const char *desc, void *p)
>>  #define KVM_S390_VIRTIO_SET_STATUS      2
>>  #define KVM_S390_VIRTIO_CCW_NOTIFY      3
>>  
>> -static inline void yield(void)
>> -{
>> -    asm volatile ("diag 0,0,0x44"
>> -                  : :
>> -                  : "memory", "cc");
>> -}
>> -
>>  #define MAX_SECTOR_SIZE 4096
>>  
>> -static inline void sleep(unsigned int seconds)
>> -{
>> -    ulong target = get_second() + seconds;
>> -
>> -    while (get_second() < target) {
>> -        yield();
>> -    }
>> -}
>> -
>>  static inline void IPL_assert(bool term, const char *message)
>>  {
>>      if (!term) {
>> diff --git a/pc-bios/s390-ccw/virtio-net.c b/pc-bios/s390-ccw/virtio-net.c
>> index 4de03728bb..f018d58994 100644
>> --- a/pc-bios/s390-ccw/virtio-net.c
>> +++ b/pc-bios/s390-ccw/virtio-net.c
>> @@ -20,6 +20,7 @@
>>  #include "s390-ccw.h"
>>  #include "virtio.h"
>>  #include "time.h"
>> +#include "helper.h"
>>  
>>  #ifndef DEBUG_VIRTIO_NET
>>  #define DEBUG_VIRTIO_NET 0
>> diff --git a/pc-bios/s390-ccw/virtio-scsi.c b/pc-bios/s390-ccw/virtio-scsi.c
>> index 0620651da8..907f8a08bd 100644
>> --- a/pc-bios/s390-ccw/virtio-scsi.c
>> +++ b/pc-bios/s390-ccw/virtio-scsi.c
>> @@ -15,6 +15,7 @@
>>  #include "scsi.h"
>>  #include "virtio-scsi.h"
>>  #include "time.h"
>> +#include "helper.h"
>>  
>>  static ScsiDevice default_scsi_device;
>>  static VirtioScsiCmdReq req;
>>



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