Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic: Avoid double-deactivate of IRQs in the nested context In the… (CVE-2026-80699)

The vulnerability (CVE-2026-80699) affects the Linux kernel's KVM virtualization on arm64 architectures, specifically the virtual generic interrupt controller (vgic). In nested interrupt contexts, the physical interrupt is already deactivated via the hardware bit in the List Register (LR). An additional deactivation, while normally harmless, triggers an errata on AmpereOne processors. This errata causes the CPU to lose the interrupt pending state and prevents delivery of future interrupts when a non-active but highest priority pending interrupt is deactivated through certain system registers (ICC_DIR_EL1 or ICC_EOIR1_EL1).

On affected systems using AmpereOne CPUs, this vulnerability can cause loss of interrupt pending state and prevent future interrupts from being delivered, potentially impacting system responsiveness or stability in virtualized environments using KVM on arm64. The issue is specific to the hardware errata triggered by the double deactivation of interrupts in nested contexts.

A fix has been implemented in the Linux kernel to avoid the double deactivation of interrupts in the nested context, thereby preventing the errata condition on AmpereOne CPUs. Users should apply the official kernel updates that include this fix. Since this is a kernel-level issue, updating to a patched kernel version is the recommended remediation.