Re: [PATCH v3 0/3] KVM: x86: Out-of-bounds access in kvm_recalculate_phys_map()

[Sean Christopherson]

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