Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: GICv2: Don't WARN on out-of-range GICV_DIR INTID

vgic_v2_deactivate() passes the INTID a guest wrote to GICV_DIR straight to vgic_get_vcpu_irq(), and treats a failed lookup as a "can't happen" condition with WARN_ON_ONCE().

The guest can make it happen at will, though: for any INTID outside of the implemented SGI, PPI and SPI ranges the lookup returns NULL, since GICv2 has no LPIs. A guest running with EOImode==1 writing such an INTID to GICV_DIR triggers the WARN, and panics hosts running with panic_on_warn.

Drop the WARN and ignore failed lookups.