From: Janosch Frank <frankja@linux.ibm.com>
Date: Mon, 10 Feb 2020 04:27:47 -0500
Subject: KVM: s390: protvirt: Do only reset registers that are accessible
Git-commit: 0f3035047140b3dc18fc5a028ed5f273f24b5539
Patch-mainline: v5.7-rc1
References: jsc#SLE-7512 bsc#1165545

For protected VMs the hypervisor can not access guest breaking event
address, program parameter, bpbc and todpr. Do not reset those fields
as the control block does not provide access to these fields.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/kvm/kvm-s390.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3512,7 +3512,6 @@ static void kvm_arch_vcpu_ioctl_initial_
 	kvm_s390_set_prefix(vcpu, 0);
 	kvm_s390_set_cpu_timer(vcpu, 0);
 	vcpu->arch.sie_block->ckc = 0;
-	vcpu->arch.sie_block->todpr = 0;
 	memset(vcpu->arch.sie_block->gcr, 0, sizeof(vcpu->arch.sie_block->gcr));
 	vcpu->arch.sie_block->gcr[0] = CR0_INITIAL_MASK;
 	vcpu->arch.sie_block->gcr[14] = CR14_INITIAL_MASK;
@@ -3530,9 +3529,17 @@ static void kvm_arch_vcpu_ioctl_initial_
 	vcpu->run->s.regs.pp = 0;
 	vcpu->run->s.regs.gbea = 1;
 	vcpu->run->s.regs.fpc = 0;
-	vcpu->arch.sie_block->gbea = 1;
-	vcpu->arch.sie_block->pp = 0;
-	vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
+	/*
+	 * Do not reset these registers in the protected case, as some of
+	 * them are overlayed and they are not accessible in this case
+	 * anyway.
+	 */
+	if (!kvm_s390_pv_cpu_is_protected(vcpu)) {
+		vcpu->arch.sie_block->gbea = 1;
+		vcpu->arch.sie_block->pp = 0;
+		vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
+		vcpu->arch.sie_block->todpr = 0;
+	}
 }
 
 static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu)