[PATCH v4 0/1] KVM: s390: diag9c (directed yield) forwarding

[Pierre Morel <pmorel@linux.ibm.com>]

This patch will forward the yield_to hypercall (diag9c) if in the host
the target CPU is also not running. As we do not yet have performance
data (and recommendations) the default is turned off, but this can
be changed during runtime.

The documentation notation for the titles is kept coherent with
the other DIAGNOSE entries using the zVM notation DIAGNOSE 'X'9C,
While in the explanation part we use the standard Linux notation
DIAGNOSE 0x9c.

Regards,
Pierre


Pierre Morel (1):
  KVM: s390: diag9c (directed yield) forwarding

 Documentation/virt/kvm/s390-diag.rst | 33 ++++++++++++++++++++++++++++
 arch/s390/include/asm/kvm_host.h     |  1 +
 arch/s390/include/asm/smp.h          |  1 +
 arch/s390/kernel/smp.c               |  1 +
 arch/s390/kvm/diag.c                 | 31 +++++++++++++++++++++++---
 arch/s390/kvm/kvm-s390.c             |  6 +++++
 arch/s390/kvm/kvm-s390.h             |  8 +++++++
 7 files changed, 78 insertions(+), 3 deletions(-)

-- 
2.17.1

Changelog:

From v3:

- rewording of the commit message
  (Connie)

- great rewording of the documentation
  (Connie)

- Keep smp_yield_cpu symbol GPL
  (Connie)

- More explicit diag9c_forwarding_hz parameter description
  (Connie)

From v2:

- update overrun comparison, avoid comparison on unsigned
  (Pierre)

From v1:

- more precise comments
  (Connie)

- Documentation
  (Janosch)