KVM: s390: pv: make use of ultravisor AIV support

This patch enables the ultravisor adapter interruption vitualization
support indicated by UV feature BIT_UV_FEAT_AIV. This allows ISC
interruption injection directly into the GISA IPM for PV kvm guests.

Hardware that does not support this feature will continue to use the
UV interruption interception method to deliver ISC interruptions to
PV kvm guests. For this purpose, the ECA_AIV bit for all guest cpus
will be cleared and the GISA will be disabled during PV CPU setup.

In addition a check in __inject_io() has been removed. That reduces the
required instructions for interruption handling for PV and traditional
kvm guests.

Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20220209152217.1793281-2-mimu@linux.ibm.com
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

1 files changed, 48 insertions, 6 deletions

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index db933c252dbc..9b30beac904d 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1901,13 +1901,12 @@ static int __inject_io(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
 	isc = int_word_to_isc(inti->io.io_int_word);
 
 	/*
-	 * Do not make use of gisa in protected mode. We do not use the lock
-	 * checking variant as this is just a performance optimization and we
-	 * do not hold the lock here. This is ok as the code will pick
-	 * interrupts from both "lists" for delivery.
+	 * We do not use the lock checking variant as this is just a
+	 * performance optimization and we do not hold the lock here.
+	 * This is ok as the code will pick interrupts from both "lists"
+	 * for delivery.
 	 */
-	if (!kvm_s390_pv_get_handle(kvm) &&
-	    gi->origin && inti->type & KVM_S390_INT_IO_AI_MASK) {
+	if (gi->origin && inti->type & KVM_S390_INT_IO_AI_MASK) {
 		VM_EVENT(kvm, 4, "%s isc %1u", "inject: I/O (AI/gisa)", isc);
 		gisa_set_ipm_gisc(gi->origin, isc);
 		kfree(inti);
@@ -3171,9 +3170,33 @@ void kvm_s390_gisa_init(struct kvm *kvm)
 	VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin);
 }
 
+void kvm_s390_gisa_enable(struct kvm *kvm)
+{
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+	struct kvm_vcpu *vcpu;
+	unsigned long i;
+	u32 gisa_desc;
+
+	if (gi->origin)
+		return;
+	kvm_s390_gisa_init(kvm);
+	gisa_desc = kvm_s390_get_gisa_desc(kvm);
+	if (!gisa_desc)
+		return;
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		mutex_lock(&vcpu->mutex);
+		vcpu->arch.sie_block->gd = gisa_desc;
+		vcpu->arch.sie_block->eca |= ECA_AIV;
+		VCPU_EVENT(vcpu, 3, "AIV gisa format-%u enabled for cpu %03u",
+			   vcpu->arch.sie_block->gd & 0x3, vcpu->vcpu_id);
+		mutex_unlock(&vcpu->mutex);
+	}
+}
+
 void kvm_s390_gisa_destroy(struct kvm *kvm)
 {
 	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+	struct kvm_s390_gisa *gisa = gi->origin;
 
 	if (!gi->origin)
 		return;
@@ -3184,6 +3207,25 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
 		cpu_relax();
 	hrtimer_cancel(&gi->timer);
 	gi->origin = NULL;
+	VM_EVENT(kvm, 3, "gisa 0x%pK destroyed", gisa);
+}
+
+void kvm_s390_gisa_disable(struct kvm *kvm)
+{
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+	struct kvm_vcpu *vcpu;
+	unsigned long i;
+
+	if (!gi->origin)
+		return;
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		mutex_lock(&vcpu->mutex);
+		vcpu->arch.sie_block->eca &= ~ECA_AIV;
+		vcpu->arch.sie_block->gd = 0U;
+		mutex_unlock(&vcpu->mutex);
+		VCPU_EVENT(vcpu, 3, "AIV disabled for cpu %03u", vcpu->vcpu_id);
+	}
+	kvm_s390_gisa_destroy(kvm);
 }
 
 /**