Re: [PATCH v2 2/5] apic: add support for x2APIC mode

[David Woodhouse <dwmw2@infradead.org>]

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On Mon, 2023-03-27 at 22:45 +0700, Bui Quang Minh wrote:
> 
> > Maybe I'm misreading the patch, but to me it looks that
> > if (dest == 0xff) apic_get_broadcast_bitmask() bit applies even in
> > x2apic mode? So delivering to the APIC with physical ID 255 will be
> > misinterpreted as a broadcast?
> 
> In case dest == 0xff the second argument to apic_get_broadcast_bitmask 
> is set to false which means this is xAPIC broadcast

Yeah, but it *isn't* xAPIC broadcast. It's X2APIC unicast to APIC#255.

I think you want (although you don't have 'dev') something like this:


static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,
                                      uint32_t dest, uint8_t dest_mode)
{
    APICCommonState *apic_iter;
    int i;

    memset(deliver_bitmask, 0x00, max_apic_words * sizeof(uint32_t));

    /* x2APIC broadcast id for both physical and logical (cluster) mode */
    if (dest == 0xffffffff) {
        apic_get_broadcast_bitmask(deliver_bitmask, true);
        return;
    }

    if (dest_mode == 0) {
        apic_find_dest(deliver_bitmask, dest);
        /* Broadcast to xAPIC mode apics */
-        if (dest == 0xff) {
+        if (dest == 0xff && is_x2apic_mode(dev)) {
            apic_get_broadcast_bitmask(deliver_bitmask, false);
        }
    } else {


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