KVM: s390: Unlink vcpu on destroy - v2
This patch makes sure we do unlink a vcpu's sie control block
from the system control area in kvm_arch_vcpu_destroy. This
prevents illegal accesses to the sie control block from other
virtual cpus after free.
Reported-by: Mijo Safradin <mijo@linux.vnet.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 36c654d..628494a 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -196,6 +196,10 @@
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
VCPU_EVENT(vcpu, 3, "%s", "free cpu");
+ if (vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sda ==
+ (__u64) vcpu->arch.sie_block)
+ vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sda = 0;
+ smp_mb();
free_page((unsigned long)(vcpu->arch.sie_block));
kvm_vcpu_uninit(vcpu);
kfree(vcpu);
@@ -310,8 +314,10 @@
vcpu->arch.sie_block->icpua = id;
BUG_ON(!kvm->arch.sca);
- BUG_ON(kvm->arch.sca->cpu[id].sda);
- kvm->arch.sca->cpu[id].sda = (__u64) vcpu->arch.sie_block;
+ if (!kvm->arch.sca->cpu[id].sda)
+ kvm->arch.sca->cpu[id].sda = (__u64) vcpu->arch.sie_block;
+ else
+ BUG_ON(!kvm->vcpus[id]); /* vcpu does already exist */
vcpu->arch.sie_block->scaoh = (__u32)(((__u64)kvm->arch.sca) >> 32);
vcpu->arch.sie_block->scaol = (__u32)(__u64)kvm->arch.sca;