CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's KVM component, specifically in the handling of VNCR TLB invalidations during concurrent operations on virtual CPUs (vCPUs). If not properly managed, this can lead to inconsistent memory translations, potentially allowing one vCPU to operate on invalid memory entries, which could compromise system stability or security. Organizations utilizing Linux-based virtualization environments, particularly those leveraging KVM on arm64 architecture, should prioritize addressing this issue to ensure the integrity and reliability of their virtualized workloads.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry A VNCR TLB invalidation can occur on one vcpu while another vcpu is faulting in this same page. Without correctly handling this, we can end up with the following scenario: - vcpu A walks the PTs to translate VNCR - before vcpu A is able to grab the MMU lock to insert the TLB, vcpu B updates the S1 PTs with an invalid entry, and issues a TLBI S1E2 for this VA - vcpu A inserts the TLB for something that is now invalid This isn't a new problem, and we manage S2 by having the MMU notifier to bump up mmu_invalidate_seq on invalidation so that the fault can be replayed. We can perform something similar here, and extend invalidate_vncr_va() to update the same counter, clearly indicating that the context has changed under our feet. This is safe as the invalidation always happen while holding the MMU lock for write, and that we sample the sequence number before walking S1.