FAILED: patch "[PATCH] KVM: arm/arm64: vgic: Avoid injecting reserved IRQ numbers" failed to apply to 4.0-stable tree

The patch below does not apply to the 4.0-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Marc Zyngier <[email protected]>
Date: Wed, 17 Jun 2015 14:43:35 +0100
Subject: [PATCH] KVM: arm/arm64: vgic: Avoid injecting reserved IRQ numbers

Commit fd1d0ddf2ae9 (KVM: arm/arm64: check IRQ number on userland injection) rightly limited the range of interrupts userspace can inject in a guest, but failed to consider the (unlikely) case where a guest is configured with 1024 interrupts.

In this case, interrupts ranging from 1020 to 1023 are unuseable, as they have a special meaning for the GIC CPU interface.

Make sure that these number cannot be used as an IRQ. Also delete a redundant (and similarily buggy) check in kvm_set_irq.

index 78fb8201014f..950064a0942d 100644
@@ -1561,7 +1561,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
 			goto out;
 	}
 
-	if (irq_num >= kvm->arch.vgic.nr_irqs)
+	if (irq_num >= min(kvm->arch.vgic.nr_irqs, 1020))
 		return -EINVAL;
 
 	vcpu_id = vgic_update_irq_pending(kvm, cpuid, irq_num, level);

@@ -2161,10 +2161,7 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id,
 
 	BUG_ON(!vgic_initialized(kvm));
 
-	if (spi > kvm->arch.vgic.nr_irqs)
-		return -EINVAL;
 	return kvm_vgic_inject_irq(kvm, 0, spi, level);
-
 }
 
 /* MSI not implemented yet */