CVE-2026-64287

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

KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU

flush_hyp_vcpu() copies the host vGIC state into the hyp's private vCPU

on every run. The vGIC list register save and restore use used_lrs as

their loop bound and expect it to stay within the number of implemented

list registers. While this is generally the case, flush_hyp_vcpu()

copies vgic_v3 verbatim and does not enforce this, so a value provided

by the host is used at EL2 to index vgic_lr[] and access ICH_LR<n>_EL2

(host -> EL2).

Fix by clamping used_lrs to the number of implemented list registers

after the copy, as the trusted path already does in

vgic_flush_lr_state(). The number of implemented list registers is

constant after init, so it is replicated once from

kvm_vgic_global_state.nr_lr into hyp_gicv3_nr_lr rather than read on

every entry.