KVM: s390: interprocessor communication via sigp

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: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 5a17176fb64..c632180739e 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -57,6 +57,12 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "instruction_chsc", VCPU_STAT(instruction_chsc) },
 	{ "instruction_stsi", VCPU_STAT(instruction_stsi) },
 	{ "instruction_stfl", VCPU_STAT(instruction_stfl) },
+	{ "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },
+	{ "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },
+	{ "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },
+	{ "instruction_sigp_set_arch", VCPU_STAT(instruction_sigp_arch) },
+	{ "instruction_sigp_set_prefix", VCPU_STAT(instruction_sigp_prefix) },
+	{ "instruction_sigp_restart", VCPU_STAT(instruction_sigp_restart) },
 	{ NULL }
 };
 
@@ -287,6 +293,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 	spin_lock_bh(&kvm->arch.float_int.lock);
 	kvm->arch.float_int.local_int[id] = &vcpu->arch.local_int;
 	init_waitqueue_head(&vcpu->arch.local_int.wq);
+	vcpu->arch.local_int.cpuflags = &vcpu->arch.sie_block->cpuflags;
 	spin_unlock_bh(&kvm->arch.float_int.lock);
 
 	rc = kvm_vcpu_init(vcpu, kvm, id);