We currently do not notify all gmaps when using gmap_pmdp_xchg(), due
to locking constraints. This makes ucontrol vms, which is the only vm
type that creates multiple gmaps, incompatible with huge pages.
ucontrol vms are rather exotic and creating a new locking concept is
no easy task. Hence we return EINVAL when trying to active
KVM_CAP_S390_HPAGE_1M and report it as being not available when
checking for it.
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
arch/s390/kvm/kvm-s390.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index f9d90337e64a..549f38d1baa1 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -481,7 +481,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
break;
case KVM_CAP_S390_HPAGE_1M:
r = 0;
- if (hpage)
+ if (hpage && !kvm_is_ucontrol(kvm))
r = 1;
break;
case KVM_CAP_S390_MEM_OP:
@@ -691,7 +691,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
mutex_lock(&kvm->lock);
if (kvm->created_vcpus)
r = -EBUSY;
- else if (!hpage || kvm->arch.use_cmma)
+ else if (!hpage || kvm->arch.use_cmma || kvm_is_ucontrol(kvm))
r = -EINVAL;
else {
r = 0;
--
2.14.3
