Update Linux to v5.10.109

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz

Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 45634b3..5b8ec1c 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -2,7 +2,7 @@
 /*
  * handling diagnose instructions
  *
- * Copyright IBM Corp. 2008, 2011
+ * Copyright IBM Corp. 2008, 2020
  *
  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  *               Christian Borntraeger <borntraeger@de.ibm.com>
@@ -10,7 +10,6 @@
 
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
-#include <asm/pgalloc.h>
 #include <asm/gmap.h>
 #include <asm/virtio-ccw.h>
 #include "kvm-s390.h"
@@ -158,14 +157,28 @@
 
 	tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
 	vcpu->stat.diagnose_9c++;
-	VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
 
+	/* yield to self */
 	if (tid == vcpu->vcpu_id)
-		return 0;
+		goto no_yield;
 
+	/* yield to invalid */
 	tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid);
-	if (tcpu)
-		kvm_vcpu_yield_to(tcpu);
+	if (!tcpu)
+		goto no_yield;
+
+	/* target already running */
+	if (READ_ONCE(tcpu->cpu) >= 0)
+		goto no_yield;
+
+	if (kvm_vcpu_yield_to(tcpu) <= 0)
+		goto no_yield;
+
+	VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: done", tid);
+	return 0;
+no_yield:
+	VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: ignored", tid);
+	vcpu->stat.diagnose_9c_ignored++;
 	return 0;
 }
 
@@ -187,6 +200,10 @@
 		return -EOPNOTSUPP;
 	}
 
+	/*
+	 * no need to check the return value of vcpu_stop as it can only have
+	 * an error for protvirt, but protvirt means user cpu state
+	 */
 	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
 		kvm_s390_vcpu_stop(vcpu);
 	vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;