KVM: s390: Support Configuration z/Architecture Mode

kvm has always supported the concept of starting in z/Arch mode so let's
reflect the feature bit to the guest.

Also, we change sigp set architecture to reject any request to change
architecture modes.

Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

2 files changed, 18 insertions, 19 deletions

diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index 1a252f537081..9d592ef4104b 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -155,29 +155,26 @@ static int __sigp_stop_and_store_status(struct kvm_vcpu *vcpu,
         return rc;
 }
 
-static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
+static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter,
+                           u64 *status_reg)
 {
-        int rc;
         unsigned int i;
         struct kvm_vcpu *v;
+        bool all_stopped = true;
 
-        switch (parameter & 0xff) {
-        case 0:
-                rc = SIGP_CC_NOT_OPERATIONAL;
-                break;
-        case 1:
-        case 2:
-                kvm_for_each_vcpu(i, v, vcpu->kvm) {
-                        v->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
-                        kvm_clear_async_pf_completion_queue(v);
-                }
-
-                rc = SIGP_CC_ORDER_CODE_ACCEPTED;
-                break;
-        default:
-                rc = -EOPNOTSUPP;
+        kvm_for_each_vcpu(i, v, vcpu->kvm) {
+                if (v == vcpu)
+                        continue;
+                if (!is_vcpu_stopped(v))
+                        all_stopped = false;
         }
-        return rc;
+
+        *status_reg &= 0xffffffff00000000UL;
+
+        /* Reject set arch order, with czam we're always in z/Arch mode. */
+        *status_reg |= (all_stopped ? SIGP_STATUS_INVALID_PARAMETER :
+                                        SIGP_STATUS_INCORRECT_STATE);
+        return SIGP_CC_STATUS_STORED;
 }
 
 static int __sigp_set_prefix(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
@@ -446,7 +443,8 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
         switch (order_code) {
         case SIGP_SET_ARCHITECTURE:
                 vcpu->stat.instruction_sigp_arch++;
-                rc = __sigp_set_arch(vcpu, parameter);
+                rc = __sigp_set_arch(vcpu, parameter,
+                                     &vcpu->run->s.regs.gprs[r1]);
                 break;
         default:
                 rc = handle_sigp_dst(vcpu, order_code, cpu_addr,
diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c
index 025ea20fc4b4..181db5b8f8b3 100644
--- a/arch/s390/tools/gen_facilities.c
+++ b/arch/s390/tools/gen_facilities.c
@@ -80,6 +80,7 @@ static struct facility_def facility_defs[] = {
                         78, /* enhanced-DAT 2 */
                         130, /* instruction-execution-protection */
                         131, /* enhanced-SOP 2 and side-effect */
+                        138, /* configuration z/architecture mode (czam) */
                         146, /* msa extension 8 */
                         -1  /* END */
                 }