• Christian Borntraeger's avatar
    KVM: s390: interprocessor communication via sigp · 5288fbf0
    Christian Borntraeger authored
    This patch introduces in-kernel handling of _some_ sigp interprocessor
    signals (similar to ipi).
    kvm_s390_handle_sigp() decodes the sigp instruction and calls individual
    handlers depending on the operation requested:
    - sigp sense tries to retrieve information such as existence or running state
      of the remote cpu
    - sigp emergency sends an external interrupt to the remove cpu
    - sigp stop stops a remove cpu
    - sigp stop store status stops a remote cpu, and stores its entire internal
      state to the cpus lowcore
    - sigp set arch sets the architecture mode of the remote cpu. setting to
      ESAME (s390x 64bit) is accepted, setting to ESA/S390 (s390, 31 or 24 bit) is
      denied, all others are passed to userland
    - sigp set prefix sets the prefix register of a remote cpu
    
    For implementation of this, the stop intercept indication starts to get reused
    on purpose: a set of action bits defines what to do once a cpu gets stopped:
    ACTION_STOP_ON_STOP  really stops the cpu when a stop intercept is recognized
    ACTION_STORE_ON_STOP stores the cpu status to lowcore when a stop intercept is
                         recognized
    Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
    Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
    Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
    Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
    5288fbf0
kvm_host.h 5.51 KB