KVM: s390: take care of clock-comparator sign control

Missed when enabling the Multiple-epoch facility. If the facility is
installed and the control is set, a sign based comaprison has to be
performed.

Right now we would inject wrong interrupts and ignore interrupt
conditions. Also the sleep time is calculated in a wrong way.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180207114647.6220-2-david@redhat.com>
Fixes: 8fa1696ea781 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 19 insertions, 6 deletions

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 3f2c49b1a393..b04616b57a94 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -169,8 +169,15 @@ static int ckc_interrupts_enabled(struct kvm_vcpu *vcpu)
 
 static int ckc_irq_pending(struct kvm_vcpu *vcpu)
 {
-        if (vcpu->arch.sie_block->ckc >= kvm_s390_get_tod_clock_fast(vcpu->kvm))
+        const u64 now = kvm_s390_get_tod_clock_fast(vcpu->kvm);
+        const u64 ckc = vcpu->arch.sie_block->ckc;
+
+        if (vcpu->arch.sie_block->gcr[0] & 0x0020000000000000ul) {
+                if ((s64)ckc >= (s64)now)
+                        return 0;
+        } else if (ckc >= now) {
                 return 0;
+        }
         return ckc_interrupts_enabled(vcpu);
 }
 
@@ -1047,13 +1054,19 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 
 static u64 __calculate_sltime(struct kvm_vcpu *vcpu)
 {
-        u64 now, cputm, sltime = 0;
+        const u64 now = kvm_s390_get_tod_clock_fast(vcpu->kvm);
+        const u64 ckc = vcpu->arch.sie_block->ckc;
+        u64 cputm, sltime = 0;
 
         if (ckc_interrupts_enabled(vcpu)) {
-                now = kvm_s390_get_tod_clock_fast(vcpu->kvm);
-                sltime = tod_to_ns(vcpu->arch.sie_block->ckc - now);
-                /* already expired or overflow? */
-                if (!sltime || vcpu->arch.sie_block->ckc <= now)
+                if (vcpu->arch.sie_block->gcr[0] & 0x0020000000000000ul) {
+                        if ((s64)now < (s64)ckc)
+                                sltime = tod_to_ns((s64)ckc - (s64)now);
+                } else if (now < ckc) {
+                        sltime = tod_to_ns(ckc - now);
+                }
+                /* already expired */
+                if (!sltime)
                         return 0;
                 if (cpu_timer_interrupts_enabled(vcpu)) {
                         cputm = kvm_s390_get_cpu_timer(vcpu);