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Subject[PATCH 4.14 086/110] KVM: s390: take care of clock-comparator sign control
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Hildenbrand <david@redhat.com>

commit 5fe01793dd953ab947fababe8abaf5ed5258c8df upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/s390/kvm/interrupt.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)

--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -173,8 +173,15 @@ static int ckc_interrupts_enabled(struct

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);
}

@@ -1004,13 +1011,19 @@ int kvm_cpu_has_pending_timer(struct kvm

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);

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