[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH] x86/Xen: streamline (and fix) PV CPU enumeration
This started out with me noticing that "dom0_max_vcpus=<N>" with <N> larger than the number of physical CPUs reported through ACPI tables would not bring up the "excess" vCPU-s. Addressing this is the primary purpose of the change; CPU maps handling is being tidied only as far as is necessary for the change here (with the effect of also avoiding the setting up of too much per-CPU infrastructure, i.e. for CPUs which can never come online). Noticing that xen_fill_possible_map() is called way too early, whereas xen_filter_cpu_maps() is called too late (after per-CPU areas were already set up), and further observing that each of the functions serves only one of Dom0 or DomU, it looked like it was better to simplify this. Use the .get_smp_config hook instead, uniformly for Dom0 and DomU. xen_fill_possible_map() can be dropped altogether, while xen_filter_cpu_maps() is re-purposed but not otherwise changed. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> --- v2: Extend description. --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1341,10 +1341,6 @@ asmlinkage __visible void __init xen_sta xen_acpi_sleep_register(); - /* Avoid searching for BIOS MP tables */ - x86_init.mpparse.find_smp_config = x86_init_noop; - x86_init.mpparse.get_smp_config = x86_init_uint_noop; - xen_boot_params_init_edd(); #ifdef CONFIG_ACPI --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -148,28 +148,12 @@ int xen_smp_intr_init_pv(unsigned int cp return rc; } -static void __init xen_fill_possible_map(void) -{ - int i, rc; - - if (xen_initial_domain()) - return; - - for (i = 0; i < nr_cpu_ids; i++) { - rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); - if (rc >= 0) { - num_processors++; - set_cpu_possible(i, true); - } - } -} - -static void __init xen_filter_cpu_maps(void) +static void __init _get_smp_config(unsigned int early) { int i, rc; unsigned int subtract = 0; - if (!xen_initial_domain()) + if (early) return; num_processors = 0; @@ -210,7 +194,6 @@ static void __init xen_pv_smp_prepare_bo * sure the old memory can be recycled. */ make_lowmem_page_readwrite(xen_initial_gdt); - xen_filter_cpu_maps(); xen_setup_vcpu_info_placement(); /* @@ -476,5 +459,8 @@ static const struct smp_ops xen_smp_ops void __init xen_smp_init(void) { smp_ops = xen_smp_ops; - xen_fill_possible_map(); + + /* Avoid searching for BIOS MP tables */ + x86_init.mpparse.find_smp_config = x86_init_noop; + x86_init.mpparse.get_smp_config = _get_smp_config; }
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