x86: MSI start irq numbering from nr_irqs_gsi
Impact: sanitize MSI irq number ordering from top-down to bottom-up
Increase new MSI IRQs starting from nr_irqs_gsi (which is somewhere below
256), instead of decreasing from NR_IRQS. (The latter method can result
in confusingly high IRQ numbers - if NR_CPUS is set to a high value and
NR_IRQS scales up to a high value.)
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9d5674f..a3834f1 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1082,7 +1082,7 @@
ioapic_init_mappings();
/* need to wait for io_apic is mapped */
- nr_irqs = probe_nr_irqs();
+ probe_nr_irqs_gsi();
kvm_guest_init();