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| author | Dominik Dingel <dingel@linux.vnet.ibm.com> | 2014-12-01 17:24:42 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-12-15 17:08:21 +0100 |
| commit | a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2 (patch) | |
| tree | 1e8fd0810ebeb5331a8cb3ec700b023a17162aaa /Documentation/virtual | |
| parent | KVM: s390: obey kptr_restrict in traces (diff) | |
| download | linux-a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2.tar.xz linux-a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2.zip | |
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 <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/devices/vm.txt | 3 |
1 files changed, 2 insertions, 1 deletions
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 |