From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Thu, 30 Jan 2020 11:18:28 -0500
Subject: KVM: s390: protvirt: do not inject interrupts after start
Git-commit: 72f218208fa63806ebcfca7e793b095d346ee0a4
Patch-mainline: v5.7-rc1
References: jsc#SLE-7512 bsc#1165545

As PSW restart is handled by the ultravisor (and we only get a start
notification) we must re-check the PSW after a start before injecting
interrupts.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/kvm/kvm-s390.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4523,6 +4523,13 @@ int kvm_s390_vcpu_start(struct kvm_vcpu
 
 	kvm_s390_clear_cpuflags(vcpu, CPUSTAT_STOPPED);
 	/*
+	 * The real PSW might have changed due to a RESTART interpreted by the
+	 * ultravisor. We block all interrupts and let the next sie exit
+	 * refresh our view.
+	 */
+	if (kvm_s390_pv_cpu_is_protected(vcpu))
+		vcpu->arch.sie_block->gpsw.mask &= ~PSW_INT_MASK;
+	/*
 	 * Another VCPU might have used IBS while we were offline.
 	 * Let's play safe and flush the VCPU at startup.
 	 */