From a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2 Mon Sep 17 00:00:00 2001 From: Dominik Dingel Date: Mon, 1 Dec 2014 17:24:42 +0100 Subject: KVM: s390: fix mismatch between user and in-kernel guest limit While the userspace interface requests the maximum size the gmap code expects to get a maximum address. This error resulted in bigger page tables than necessary for some guest sizes, e.g. a 2GB guest used 3 levels instead of 2. At the same time we introduce KVM_S390_NO_MEM_LIMIT, which allows in a bright future that a guest spans the complete 64 bit address space. We also switch to TASK_MAX_SIZE for the initial memory size, this is a cosmetic change as the previous size also resulted in a 4 level pagetable creation. Reported-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Dominik Dingel Signed-off-by: Christian Borntraeger --- Documentation/virtual/kvm/devices/vm.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt index 2d09d1ed86d0..f083a168eb35 100644 --- a/Documentation/virtual/kvm/devices/vm.txt +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -37,7 +37,8 @@ Returns: -EFAULT if the given address is not accessible Allows userspace to query the actual limit and set a new limit for the maximum guest memory size. The limit will be rounded up to 2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by -the number of page table levels. +the number of page table levels. In the case that there is no limit we will set +the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX). 2. GROUP: KVM_S390_VM_CPU_MODEL Architectures: s390 -- cgit v1.2.3