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author | Dominik Dingel <dingel@linux.vnet.ibm.com> | 2014-12-01 17:24:42 +0100 |
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committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-12-15 17:08:21 +0100 |
commit | a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2 (patch) | |
tree | 1e8fd0810ebeb5331a8cb3ec700b023a17162aaa /arch/s390/kvm | |
parent | 8335713ad08caf2c3dfcb5bc2c93d7e0276142d4 (diff) | |
download | linux-a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2.tar.gz linux-a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2.tar.bz2 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 'arch/s390/kvm')
-rw-r--r-- | arch/s390/kvm/kvm-s390.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index c14845c3a6f8..8aa5e55a8ecd 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -378,8 +378,8 @@ static int kvm_s390_get_mem_control(struct kvm *kvm, struct kvm_device_attr *att case KVM_S390_VM_MEM_LIMIT_SIZE: ret = 0; VM_EVENT(kvm, 3, "QUERY: max guest memory: %lu bytes", - kvm->arch.gmap->asce_end); - if (put_user(kvm->arch.gmap->asce_end, (u64 __user *)attr->addr)) + kvm->arch.mem_limit); + if (put_user(kvm->arch.mem_limit, (u64 __user *)attr->addr)) ret = -EFAULT; break; default: @@ -431,9 +431,17 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att if (get_user(new_limit, (u64 __user *)attr->addr)) return -EFAULT; - if (new_limit > kvm->arch.gmap->asce_end) + if (kvm->arch.mem_limit != KVM_S390_NO_MEM_LIMIT && + new_limit > kvm->arch.mem_limit) return -E2BIG; + if (!new_limit) + return -EINVAL; + + /* gmap_alloc takes last usable address */ + if (new_limit != KVM_S390_NO_MEM_LIMIT) + new_limit -= 1; + ret = -EBUSY; mutex_lock(&kvm->lock); if (atomic_read(&kvm->online_vcpus) == 0) { @@ -450,7 +458,9 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att } } mutex_unlock(&kvm->lock); - VM_EVENT(kvm, 3, "SET: max guest memory: %lu bytes", new_limit); + VM_EVENT(kvm, 3, "SET: max guest address: %lu", new_limit); + VM_EVENT(kvm, 3, "New guest asce: 0x%pK", + (void *) kvm->arch.gmap->asce); break; } default: @@ -1172,8 +1182,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) if (type & KVM_VM_S390_UCONTROL) { kvm->arch.gmap = NULL; + kvm->arch.mem_limit = KVM_S390_NO_MEM_LIMIT; } else { - kvm->arch.gmap = gmap_alloc(current->mm, (1UL << 44) - 1); + kvm->arch.mem_limit = TASK_MAX_SIZE; + kvm->arch.gmap = gmap_alloc(current->mm, kvm->arch.mem_limit - 1); if (!kvm->arch.gmap) goto out_err; kvm->arch.gmap->private = kvm; @@ -2829,6 +2841,9 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if (mem->memory_size & 0xffffful) return -EINVAL; + if (mem->guest_phys_addr + mem->memory_size > kvm->arch.mem_limit) + return -EINVAL; + return 0; } |