On Fri, 02 Jun 2023 16:32:47 -0700, Sean Christopherson wrote: > In Michal's words... > > kvm_recalculate_apic_map() creates the APIC map iterating over the list of > vCPUs twice. First to find the max APIC ID and allocate a max-sized buffer, > then again, calling kvm_recalculate_phys_map() for each vCPU. This opens a > race window: value of max APIC ID can increase _after_ the buffer was > allocated. > > [...] Applied 1 and 3 to kvm-x86 fixes (for 6.4), figuring out how to deal with the dependencies get #2 into 6.5 is a future problem. [1/3] KVM: x86: Bail from kvm_recalculate_phys_map() if x2APIC ID is out-of-bounds https://github.com/kvm-x86/linux/commit/4364b287982b [2/3] ... [3/3] KVM: selftests: Add test for race in kvm_recalculate_apic_map() https://github.com/kvm-x86/linux/commit/47d2804bc99c -- https://github.com/kvm-x86/linux/tree/next https://github.com/kvm-x86/linux/tree/fixes