Messages in this thread | | | Subject | Re: [PATCH v1 03/11] KVM: x86: dynamic kvm_apic_map | From | Paolo Bonzini <> | Date | Fri, 1 Jul 2016 10:42:00 +0200 |
| |
On 01/07/2016 00:15, Andrew Honig wrote: >> > + /* kvm_apic_map_get_logical_dest() expects multiples of 16 */ >> > + size = round_up(max_id + 1, 16); > Now that you're using the full range of apic_id values, could this > calculation overflow? Perhaps max_id could be u64?
Good point, but I wonder if it's a good idea to let userspace allocate 32 GB of memory. :)
Let's put a limit on the maximum supported APIC ID, and report it through KVM_CHECK_EXTENSION on the new KVM_CAP_X2APIC_API capability. If 767 is enough for Knights Landing, the allocation below fits in two pages. If you need to make it higher, please change the allocation to use kvm_kvzalloc and kvfree.
Last but not least...
>> > + new = kzalloc(sizeof(struct kvm_apic_map) + >> > + sizeof(struct kvm_lapic) * size, GFP_KERNEL); ^^^^^^^^^^^^^^^^^^^^^^^^ ... the sizeof here must be sizeof(struct kvm_lapic *).
Thanks,
Paolo
| |