[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2] x86/x2apic: introduce a mixed physical/cluster mode
On 31.10.2023 15:52, Roger Pau Monne wrote: > --- a/xen/arch/x86/genapic/x2apic.c > +++ b/xen/arch/x86/genapic/x2apic.c > @@ -180,6 +180,29 @@ static const struct genapic __initconstrel > apic_x2apic_cluster = { > .send_IPI_self = send_IPI_self_x2apic > }; > > +/* > + * Mixed x2APIC mode: use physical for external (device) interrupts, and > + * cluster for inter processor interrupts. Such mode has the benefits of not > + * sharing the vector space with all CPUs on the cluster, while still > allowing > + * IPIs to be more efficiently delivered by not having to perform an ICR > write > + * for each target CPU. > + */ > +static const struct genapic __initconstrel apic_x2apic_mixed = { > + APIC_INIT("x2apic_mixed", NULL), > + /* > + * NB: IPIs use the send_IPI_{mask,self} hooks only, other fields are > + * exclusively used by external interrupts and hence are set to use > + * Physical destination mode handlers. > + */ > + .int_delivery_mode = dest_Fixed, > + .int_dest_mode = 0 /* physical delivery */, > + .init_apic_ldr = init_apic_ldr_x2apic_cluster, > + .vector_allocation_cpumask = vector_allocation_cpumask_phys, > + .cpu_mask_to_apicid = cpu_mask_to_apicid_phys, > + .send_IPI_mask = send_IPI_mask_x2apic_cluster, > + .send_IPI_self = send_IPI_self_x2apic > +}; I'm afraid the comment is still misleading in one respect: The .init_apic_ldr hook is also set to its Clustered mode handler (and validly so). As before my suggestion would be to leverage that we're using dedicated initializers here and have a Physical mode portion and a Clustered mode one, each clarifying in a brief leading comment where/how the handlers are used. Jan
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