KVM: s390: Set guest storage limit and offset to sane values

Some machines do not accept 16EB as guest storage limit. Lets change the
default for the guest storage limit to a sane value. We also should set
the guest_origin to what userspace thinks it is. This allows guests
starting at an address != 0.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/s390/kvm/kvm-s390.c

@@ -247,11 +247,16 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
 	vcpu->arch.sie_block->gbea = 1;
 }
 
+/* The current code can have up to 256 pages for virtio */
+#define VIRTIODESCSPACE (256ul * 4096ul)
+
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
 	atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH);
-	vcpu->arch.sie_block->gmslm = 0xffffffffffUL;
-	vcpu->arch.sie_block->gmsor = 0x000000000000;
+	vcpu->arch.sie_block->gmslm = vcpu->kvm->arch.guest_memsize +
+				      vcpu->kvm->arch.guest_origin +
+				      VIRTIODESCSPACE - 1ul;
+	vcpu->arch.sie_block->gmsor = vcpu->kvm->arch.guest_origin;
 	vcpu->arch.sie_block->ecb   = 2;
 	vcpu->arch.sie_block->eca   = 0xC1002001U;
 	setup_timer(&vcpu->arch.ckc_timer, kvm_s390_idle_wakeup,