KVM: s390: Limit guest size to 16TB

Currently we fill up a full 5 level page table to hold the guest mapping. Since commit "support gmap page tables with less than 5 levels" we can do better. Having more than 4 TB might be useful for some testing scenarios, so let's just limit ourselves to 16TB guest size. Having more than that is totally untested as I do not have enough swap space/memory. We continue to allow ucontrol the full size. Signed-off-by: Christian Borntraeger <[email protected]> Acked-by: Cornelia Huck <[email protected]> Cc: Martin Schwidefsky <[email protected]>
tdeneau · Sep 10, 2014 · 0349985 · 0349985
1 parent 614aeab
commit 0349985
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
@@ -458,7 +458,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (type & KVM_VM_S390_UCONTROL) {
 		kvm->arch.gmap = NULL;
 	} else {
-		kvm->arch.gmap = gmap_alloc(current->mm, -1UL);
+		kvm->arch.gmap = gmap_alloc(current->mm, (1UL << 44) - 1);
 		if (!kvm->arch.gmap)
 			goto out_nogmap;
 		kvm->arch.gmap->private = kvm;