KVM: s390: forward most SIGP orders to user space
Most SIGP orders are handled partially in kernel and partially in
user space. In order to:
- Get a correct SIGP SET PREFIX handler that informs user space
- Avoid race conditions between concurrently executed SIGP orders
- Serialize SIGP orders per VCPU
We need to handle all "slow" SIGP orders in user space. The remaining
ones to be handled completely in kernel are:
- SENSE
- SENSE RUNNING
- EXTERNAL CALL
- EMERGENCY SIGNAL
- CONDITIONAL EMERGENCY SIGNAL
According to the PoP, they have to be fast. They can be executed
without conflicting to the actions of other pending/concurrently
executing orders (e.g. STOP vs. START).
This patch introduces a new capability that will - when enabled -
forward all but the mentioned SIGP orders to user space. The
instruction counters in the kernel are still updated.
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index 1524be9..23b1e86 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -371,6 +371,53 @@
return rc;
}
+static int handle_sigp_order_in_user_space(struct kvm_vcpu *vcpu, u8 order_code)
+{
+ if (!vcpu->kvm->arch.user_sigp)
+ return 0;
+
+ switch (order_code) {
+ case SIGP_SENSE:
+ case SIGP_EXTERNAL_CALL:
+ case SIGP_EMERGENCY_SIGNAL:
+ case SIGP_COND_EMERGENCY_SIGNAL:
+ case SIGP_SENSE_RUNNING:
+ return 0;
+ /* update counters as we're directly dropping to user space */
+ case SIGP_STOP:
+ vcpu->stat.instruction_sigp_stop++;
+ break;
+ case SIGP_STOP_AND_STORE_STATUS:
+ vcpu->stat.instruction_sigp_stop_store_status++;
+ break;
+ case SIGP_STORE_STATUS_AT_ADDRESS:
+ vcpu->stat.instruction_sigp_store_status++;
+ break;
+ case SIGP_SET_PREFIX:
+ vcpu->stat.instruction_sigp_prefix++;
+ break;
+ case SIGP_START:
+ vcpu->stat.instruction_sigp_start++;
+ break;
+ case SIGP_RESTART:
+ vcpu->stat.instruction_sigp_restart++;
+ break;
+ case SIGP_INITIAL_CPU_RESET:
+ vcpu->stat.instruction_sigp_init_cpu_reset++;
+ break;
+ case SIGP_CPU_RESET:
+ vcpu->stat.instruction_sigp_cpu_reset++;
+ break;
+ default:
+ vcpu->stat.instruction_sigp_unknown++;
+ }
+
+ VCPU_EVENT(vcpu, 4, "sigp order %u: completely handled in user space",
+ order_code);
+
+ return 1;
+}
+
int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
{
int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
@@ -385,6 +432,8 @@
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
order_code = kvm_s390_get_base_disp_rs(vcpu);
+ if (handle_sigp_order_in_user_space(vcpu, order_code))
+ return -EOPNOTSUPP;
if (r1 % 2)
parameter = vcpu->run->s.regs.gprs[r1];
