[Xen-devel] [PATCH] x86/boot: silence MADT table entry logging

["Jan Beulich" <JBeulich@xxxxxxxx>]

Logging disabled LAPIC / x2APIC entries with invalid local APIC IDs
(ones having "broadcast" meaning when used) isn't very useful, and can
be quite noisy on larger systems. Suppress their logging unless
opt_cpu_info is true.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/acpi/boot.c
+++ b/xen/arch/x86/acpi/boot.c
@@ -83,21 +83,26 @@ acpi_parse_x2apic(struct acpi_subtable_h
 {
        struct acpi_madt_local_x2apic *processor =
                container_of(header, struct acpi_madt_local_x2apic, header);
-       bool enabled = false;
+       bool enabled = false, log = false;
 
        if (BAD_MADT_ENTRY(processor, end))
                return -EINVAL;
 
-       acpi_table_print_madt_entry(header);
+       if ((processor->lapic_flags & ACPI_MADT_ENABLED) ||
+           processor->local_apic_id != 0xffffffff || opt_cpu_info) {
+               acpi_table_print_madt_entry(header);
+               log = true;
+       }
 
        /* Record local apic id only when enabled and fitting. */
        if (processor->local_apic_id >= MAX_APICS ||
            processor->uid >= MAX_MADT_ENTRIES) {
-               printk("%sAPIC ID %#x and/or ACPI ID %#x beyond limit"
-                      " - processor ignored\n",
-                      processor->lapic_flags & ACPI_MADT_ENABLED ?
-                               KERN_WARNING "WARNING: " : KERN_INFO,
-                      processor->local_apic_id, processor->uid);
+               if (log)
+                       printk("%sAPIC ID %#x and/or ACPI ID %#x beyond limit"
+                              " - processor ignored\n",
+                              processor->lapic_flags & ACPI_MADT_ENABLED
+                              ? KERN_WARNING "WARNING: " : KERN_INFO,
+                              processor->local_apic_id, processor->uid);
                /*
                 * Must not return an error here, to prevent
                 * acpi_table_parse_entries() from terminating early.
@@ -132,7 +137,9 @@ acpi_parse_lapic(struct acpi_subtable_he
        if (BAD_MADT_ENTRY(processor, end))
                return -EINVAL;
 
-       acpi_table_print_madt_entry(header);
+       if ((processor->lapic_flags & ACPI_MADT_ENABLED) ||
+           processor->id != 0xff || opt_cpu_info)
+               acpi_table_print_madt_entry(header);
 
        /* Record local apic id only when enabled */
        if (processor->lapic_flags & ACPI_MADT_ENABLED) {





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