commit 25ed16759660cdfccd4a3cb7d30cce8a797b542a
author David Hildenbrand <dahi@linux.vnet.ibm.com> Tue May 12 09:49:14 2015 +0200
committer Christian Borntraeger <borntraeger@de.ibm.com> Tue Oct 13 15:50:35 2015 +0200
tree 4aafb77404f7fede2ac763509169a0f586b21c9e
parent 5a3d883a59b3fe8dc8775c7a79200a5b11a6761e

KVM: s390: factor out and fix setting of guest TOD clock

Let's move that whole logic into one function. We now always use unsigned
values when calculating the epoch (to avoid over/underflow defined).
Also, we always have to get all VCPUs out of SIE before doing the update
to avoid running differing VCPUs with different TODs.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/kvm/kvm-s390.c

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index a090779..87bd602 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -521,22 +521,12 @@
 
 static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
 {
-	struct kvm_vcpu *cur_vcpu;
-	unsigned int vcpu_idx;
 	u64 gtod;
 
 	if (copy_from_user(&gtod, (void __user *)attr->addr, sizeof(gtod)))
 		return -EFAULT;
 
-	mutex_lock(&kvm->lock);
-	preempt_disable();
-	kvm->arch.epoch = gtod - get_tod_clock();
-	kvm_s390_vcpu_block_all(kvm);
-	kvm_for_each_vcpu(vcpu_idx, cur_vcpu, kvm)
-		cur_vcpu->arch.sie_block->epoch = kvm->arch.epoch;
-	kvm_s390_vcpu_unblock_all(kvm);
-	preempt_enable();
-	mutex_unlock(&kvm->lock);
+	kvm_s390_set_tod_clock(kvm, gtod);
 	VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx\n", gtod);
 	return 0;
 }
@@ -1906,6 +1896,22 @@
 	return 0;
 }
 
+void kvm_s390_set_tod_clock(struct kvm *kvm, u64 tod)
+{
+	struct kvm_vcpu *vcpu;
+	int i;
+
+	mutex_lock(&kvm->lock);
+	preempt_disable();
+	kvm->arch.epoch = tod - get_tod_clock();
+	kvm_s390_vcpu_block_all(kvm);
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		vcpu->arch.sie_block->epoch = kvm->arch.epoch;
+	kvm_s390_vcpu_unblock_all(kvm);
+	preempt_enable();
+	mutex_unlock(&kvm->lock);
+}
+
 /**
  * kvm_arch_fault_in_page - fault-in guest page if necessary
  * @vcpu: The corresponding virtual cpu