From df88f3181f10565c6e3a89eb6f0f9e6afaaf15f1 Mon Sep 17 00:00:00 2001 From: Janosch Frank Date: Thu, 30 Aug 2018 16:14:18 +0200 Subject: KVM: s390: Properly lock mm context allow_gmap_hpage_1m setting We have to do down_write on the mm semaphore to set a bitfield in the mm context. Signed-off-by: Janosch Frank Fixes: a4499382 ("KVM: s390: Add huge page enablement control") Reviewed-by: Christian Borntraeger Signed-off-by: Christian Borntraeger --- arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 91ad4a9425c0..f69333fd2fa3 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -695,7 +695,9 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) r = -EINVAL; else { r = 0; + down_write(&kvm->mm->mmap_sem); kvm->mm->context.allow_gmap_hpage_1m = 1; + up_write(&kvm->mm->mmap_sem); /* * We might have to create fake 4k page * tables. To avoid that the hardware works on -- cgit v1.2.3