KVM: PPC: Book3S HV: XIVE: Clear escalation interrupt pointers on device close

This adds code to ensure that after a XIVE or XICS-on-XIVE KVM device
is closed, KVM will not try to enable or disable any of the escalation
interrupts for the VCPUs.  We don't have to worry about races between
clearing the pointers and use of the pointers by the XIVE context
push/pull code, because the callers hold the vcpu->mutex, which is
also taken by the KVM_RUN code.  Therefore the vcpu cannot be entering
or exiting the guest concurrently.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_xive.c

@@ -1096,6 +1096,21 @@ void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu)
 			arch_spin_unlock(&sb->lock);
 		}
 	}
+
+	/* Disable vcpu's escalation interrupt */
+	if (vcpu->arch.xive_esc_on) {
+		__raw_readq((void __iomem *)(vcpu->arch.xive_esc_vaddr +
+					     XIVE_ESB_SET_PQ_01));
+		vcpu->arch.xive_esc_on = false;
+	}
+
+	/*
+	 * Clear pointers to escalation interrupt ESB.
+	 * This is safe because the vcpu->mutex is held, preventing
+	 * any other CPU from concurrently executing a KVM_RUN ioctl.
+	 */
+	vcpu->arch.xive_esc_vaddr = 0;
+	vcpu->arch.xive_esc_raddr = 0;
 }
 
 void kvmppc_xive_cleanup_vcpu(struct kvm_vcpu *vcpu)