From ddadbae79c32e5aea63ca8dc8d8ae28354e5401c Mon Sep 17 00:00:00 2001 From: Janosch Frank Date: Thu, 2 Feb 2017 16:39:31 +0100 Subject: [PATCH] KVM: s390: Disable dirty log retrieval for UCONTROL guests commit e1e8a9624f7ba8ead4f056ff558ed070e86fa747 upstream. User controlled KVM guests do not support the dirty log, as they have no single gmap that we can check for changes. As they have no single gmap, kvm->arch.gmap is NULL and all further referencing to it for dirty checking will result in a NULL dereference. Let's return -EINVAL if a caller tries to sync dirty logs for a UCONTROL guest. Fixes: 15f36eb ("KVM: s390: Add proper dirty bitmap support to S390 kvm.") Signed-off-by: Janosch Frank Reported-by: Martin Schwidefsky Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger Signed-off-by: Ben Hutchings --- arch/s390/kvm/kvm-s390.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index fd8a8373c275..dcf75dfd4583 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -216,6 +216,9 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot; int is_dirty = 0; + if (kvm_is_ucontrol(kvm)) + return -EINVAL; + mutex_lock(&kvm->slots_lock); r = -EINVAL;