KVM: s390: Add new reset vcpu API

The architecture states that we need to reset local IRQs for all CPU
resets. Because the old reset interface did not support the normal CPU
reset we never did that on a normal reset.

Let's implement an interface for the missing normal and clear resets
and reset all local IRQs, registers and control structures as stated
in the architecture.

Userspace might already reset the registers via the vcpu run struct,
but as we need the interface for the interrupt clearing part anyway,
we implement the resets fully and don't rely on userspace to reset the
rest.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20200131100205.74720-4-frankja@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 57 insertions, 27 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index bb072866bd69..e39f6ef97b09 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_S390_CMMA_MIGRATION:
 	case KVM_CAP_S390_AIS:
 	case KVM_CAP_S390_AIS_MIGRATION:
+	case KVM_CAP_S390_VCPU_RESETS:
 		r = 1;
 		break;
 	case KVM_CAP_S390_HPAGE_1M:
@@ -2844,29 +2845,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 
 }
 
-static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
-{
-	/* this equals initial cpu reset in pop, but we don't switch to ESA */
-	vcpu->arch.sie_block->gpsw.mask = 0;
-	vcpu->arch.sie_block->gpsw.addr = 0;
-	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;
-	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;
-	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
-	kvm_clear_async_pf_completion_queue(vcpu);
-	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
-		kvm_s390_vcpu_stop(vcpu);
-	kvm_s390_clear_local_irqs(vcpu);
-}
-
 void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 {
 	mutex_lock(&vcpu->kvm->lock);
@@ -3281,10 +3259,53 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,
 	return r;
 }
 
-static int kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
+static void kvm_arch_vcpu_ioctl_normal_reset(struct kvm_vcpu *vcpu)
 {
-	kvm_s390_vcpu_initial_reset(vcpu);
-	return 0;
+	vcpu->arch.sie_block->gpsw.mask &= ~PSW_MASK_RI;
+	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
+	memset(vcpu->run->s.regs.riccb, 0, sizeof(vcpu->run->s.regs.riccb));
+
+	kvm_clear_async_pf_completion_queue(vcpu);
+	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
+		kvm_s390_vcpu_stop(vcpu);
+	kvm_s390_clear_local_irqs(vcpu);
+}
+
+static void kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
+{
+	/* Initial reset is a superset of the normal reset */
+	kvm_arch_vcpu_ioctl_normal_reset(vcpu);
+
+	/* this equals initial cpu reset in pop, but we don't switch to ESA */
+	vcpu->arch.sie_block->gpsw.mask = 0;
+	vcpu->arch.sie_block->gpsw.addr = 0;
+	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;
+	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;
+}
+
+static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu)
+{
+	struct kvm_sync_regs *regs = &vcpu->run->s.regs;
+
+	/* Clear reset is a superset of the initial reset */
+	kvm_arch_vcpu_ioctl_initial_reset(vcpu);
+
+	memset(&regs->gprs, 0, sizeof(regs->gprs));
+	memset(&regs->vrs, 0, sizeof(regs->vrs));
+	memset(&regs->acrs, 0, sizeof(regs->acrs));
+	memset(&regs->gscb, 0, sizeof(regs->gscb));
+
+	regs->etoken = 0;
+	regs->etoken_extension = 0;
 }
 
 int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
@@ -4357,8 +4378,17 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		r = kvm_arch_vcpu_ioctl_set_initial_psw(vcpu, psw);
 		break;
 	}
+	case KVM_S390_CLEAR_RESET:
+		r = 0;
+		kvm_arch_vcpu_ioctl_clear_reset(vcpu);
+		break;
 	case KVM_S390_INITIAL_RESET:
-		r = kvm_arch_vcpu_ioctl_initial_reset(vcpu);
+		r = 0;
+		kvm_arch_vcpu_ioctl_initial_reset(vcpu);
+		break;
+	case KVM_S390_NORMAL_RESET:
+		r = 0;
+		kvm_arch_vcpu_ioctl_normal_reset(vcpu);
 		break;
 	case KVM_SET_ONE_REG:
 	case KVM_GET_ONE_REG: {