KVM: s390: add the GIB and its related life-cyle functions

The Guest Information Block (GIB) links the GISA of all guests
that have adapter interrupts pending. These interrupts cannot be
delivered because all vcpus of these guests are currently in WAIT
state or have masked the respective Interruption Sub Class (ISC).
If enabled, a GIB alert is issued on the host to schedule these
guests to run suitable vcpus to consume the pending interruptions.

This mechanism allows to process adapter interrupts for currently
not running guests.

The GIB is created during host initialization and associated with
the Adapter Interruption Facility in case an Adapter Interruption
Virtualization Facility is available.

The GIB initialization and thus the activation of the related code
will be done in an upcoming patch of this series.
Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <20190131085247.13826-10-mimu@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -784,6 +784,15 @@ struct kvm_s390_gisa {
 	};
 };
 
+struct kvm_s390_gib {
+	u32 alert_list_origin;
+	u32 reserved01;
+	u8:5;
+	u8  nisc:3;
+	u8  reserved03[3];
+	u32 reserved04[5];
+};
+
 /*
  * sie_page2 has to be allocated as DMA because fac_list, crycb and
  * gisa need 31bit addresses in the sie control block.

arch/s390/kvm/interrupt.c

@@ -7,6 +7,9 @@
  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  */
 
+#define KMSG_COMPONENT "kvm-s390"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
 #include <linux/interrupt.h>
 #include <linux/kvm_host.h>
 #include <linux/hrtimer.h>
@@ -31,6 +34,8 @@
 #define PFAULT_DONE 0x0680
 #define VIRTIO_PARAM 0x0d00
 
+static struct kvm_s390_gib *gib;
+
 /* handle external calls via sigp interpretation facility */
 static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
 {
@@ -2914,3 +2919,41 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
 {
 	kvm->arch.gisa_int.origin = NULL;
 }
+
+void kvm_s390_gib_destroy(void)
+{
+	if (!gib)
+		return;
+	chsc_sgib(0);
+	free_page((unsigned long)gib);
+	gib = NULL;
+}
+
+int kvm_s390_gib_init(u8 nisc)
+{
+	int rc = 0;
+
+	if (!css_general_characteristics.aiv) {
+		KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
+		goto out;
+	}
+
+	gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	if (!gib) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	gib->nisc = nisc;
+	if (chsc_sgib((u32)(u64)gib)) {
+		pr_err("Associating the GIB with the AIV facility failed\n");
+		free_page((unsigned long)gib);
+		gib = NULL;
+		rc = -EIO;
+		goto out;
+	}
+
+	KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
+out:
+	return rc;
+}

arch/s390/kvm/kvm-s390.c

@@ -444,6 +444,7 @@ int kvm_arch_init(void *opaque)
 
 void kvm_arch_exit(void)
 {
+	kvm_s390_gib_destroy();
 	debug_unregister(kvm_s390_dbf);
 }
 

arch/s390/kvm/kvm-s390.h

@@ -381,6 +381,8 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu,
 void kvm_s390_gisa_init(struct kvm *kvm);
 void kvm_s390_gisa_clear(struct kvm *kvm);
 void kvm_s390_gisa_destroy(struct kvm *kvm);
+int kvm_s390_gib_init(u8 nisc);
+void kvm_s390_gib_destroy(void);
 
 /* implemented in guestdbg.c */
 void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu);