KVM: s390: Enable up to 248 VCPUs per VM

This patch allows s390 to have more than 64 VCPUs for a guest (up to
248 for memory usage considerations), if supported by the underlaying
hardware (sclp.has_esca).

Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -27,7 +27,7 @@
 
 #define KVM_S390_BSCA_CPU_SLOTS 64
 #define KVM_S390_ESCA_CPU_SLOTS 248
-#define KVM_MAX_VCPUS KVM_S390_BSCA_CPU_SLOTS
+#define KVM_MAX_VCPUS KVM_S390_ESCA_CPU_SLOTS
 #define KVM_USER_MEM_SLOTS 32
 
 /*

arch/s390/kvm/kvm-s390.c

@@ -246,7 +246,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		break;
 	case KVM_CAP_NR_VCPUS:
 	case KVM_CAP_MAX_VCPUS:
-		r = KVM_MAX_VCPUS;
+		r = sclp.has_esca ? KVM_S390_ESCA_CPU_SLOTS
+				  : KVM_S390_BSCA_CPU_SLOTS;
 		break;
 	case KVM_CAP_NR_MEMSLOTS:
 		r = KVM_USER_MEM_SLOTS;