[RFC,v1,0/6] Improvements to SIGP handling [KVM]

Message

Eric Farman Oct. 8, 2021, 8:31 p.m. UTC

I'm cleaning up some of the SIGP code in KVM and QEMU,
and would like to propose the following changes.

Patch 1 is interesting and could use some discussion, in that
CZAM cannot be disabled with QEMU (it is present in the earliest
CPU models) but the CPU model interface _could_ allow userspace
to leave it out. On the other (other?) hand, since we are always
in z/Architecture, that wouldn't make much sense as there would
probably be some other interesting side effects.

Patch 6 isn't required, but as I was looking at the intersection
of KVM capabilities S390_USER_SIGP and MP_STATE for this,
I thought some footprints could be useful.

There is no dependency on QEMU code, however another series of
patches for QEMU will follow.

Eric Farman (6):
  KVM: s390: Simplify SIGP Set Arch handling
  KVM: s390: Reject SIGP when destination CPU is busy
  KVM: s390: Simplify SIGP Restart
  KVM: s390: Restart IRQ should also block SIGP
  KVM: s390: Give BUSY to SIGP SENSE during Restart
  KVM: s390: Add a routine for setting userspace CPU state

 arch/s390/include/asm/kvm_host.h |  1 +
 arch/s390/kvm/interrupt.c        |  7 +++
 arch/s390/kvm/kvm-s390.c         |  7 +--
 arch/s390/kvm/kvm-s390.h         | 10 ++++
 arch/s390/kvm/sigp.c             | 86 +++++++++++++++++++++++---------
 5 files changed, 85 insertions(+), 26 deletions(-)