Re: [PATCH v4 19/32] KVM: x86: Explicitly track all possibilities for APIC map's logical modes

From: Paolo Bonzini
Date: Tue Dec 27 2022 - 06:31:16 EST


On 12/17/22 00:34, Sean Christopherson wrote:
On Fri, Dec 16, 2022, Sean Christopherson wrote:
On Thu, Dec 08, 2022, Maxim Levitsky wrote:

...

@@ -282,7 +291,8 @@ void kvm_recalculate_apic_map(struct kvm *kvm)
if (!apic_x2apic_mode(apic) && !new->phys_map[xapic_id])
new->phys_map[xapic_id] = apic;
- if (!kvm_apic_sw_enabled(apic))
+ if (new->logical_mode == KVM_APIC_MODE_MAP_DISABLED ||
+ !kvm_apic_sw_enabled(apic))
continue;
Very minor nitpick: it feels to me that code that updates the logical mode of the
map, might be better to be in a function, or in 'if', like

An if-statement would be rough due to the indentation. A function works well
though, especially if both the physical and logical chunks are put into helpers.
E.g. the patch at the bottom (with other fixup for this patch) yields:

new->max_apic_id = max_id;
new->logical_mode = KVM_APIC_MODE_SW_DISABLED;

kvm_for_each_vcpu(i, vcpu, kvm) {
if (!kvm_apic_present(vcpu))
continue;

if (kvm_recalculate_phys_map(new, vcpu, &xapic_id_mismatch)) {
kvfree(new);
new = NULL;
goto out;
}

kvm_recalculate_logical_map(new, vcpu);
}

I'll tack that patch on at the end of the series if it looks ok.

Yes, please send as a follow up.

Paolo