Commit 4839ddc2 authored Jun 17, 2015 by Marc Zyngier

KVM: arm/arm64: vgic: Avoid injecting reserved IRQ numbers



Commit fd1d0ddf (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.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: <stable@vger.kernel.org> # 4.1, 4.0, 3.19, 3.18
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

parent 4642019d

virt/kvm/arm/vgic.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -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 */

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