From 07806c50bddd2f0493f97584198733946952409c Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Wed, 7 Jan 2015 15:31:34 +0800 Subject: [PATCH] x86/apic: Refine enable_IR_x2apic() and related functions Refine enable_IR_x2apic() and related functions for better readability. [ tglx: Removed the XAPIC mode change and split it out into a seperate patch. Added comments. ] Signed-off-by: Jiang Liu Cc: Tony Luck Cc: iommu@lists.linux-foundation.org Cc: H. Peter Anvin Cc: Joerg Roedel Cc: Benjamin Herrenschmidt Cc: Yinghai Lu Cc: Borislav Petkov Cc: David Rientjes Cc: HATAYAMA Daisuke Cc: Jan Beulich Cc: Richard Weinberger Cc: Oren Twaig Link: http://lkml.kernel.org/r/1420615903-28253-8-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/apic/apic.c | 92 +++++++++++++++++++------------------ 1 file changed, 47 insertions(+), 45 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 11358df3bd08..fa77be8d0b17 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1573,7 +1573,7 @@ void enable_x2apic(void) } #endif /* CONFIG_X86_X2APIC */ -int __init enable_IR(void) +static int __init try_to_enable_IR(void) { #ifdef CONFIG_IRQ_REMAP if (!irq_remapping_supported()) { @@ -1586,17 +1586,51 @@ int __init enable_IR(void) "io-apic setup\n"); return -1; } - +#endif return irq_remapping_enable(); +} + +static __init void try_to_enable_x2apic(int ir_stat) +{ +#ifdef CONFIG_X86_X2APIC + if (!x2apic_supported()) + return; + + if (ir_stat < 0) { + /* IR is required if there is APIC ID > 255 even when running + * under KVM + */ + if (max_physical_apicid > 255 || + !hypervisor_x2apic_available()) { + pr_info("IRQ remapping doesn't support X2APIC mode, disable x2apic.\n"); + if (x2apic_preenabled) + disable_x2apic(); + return; + } + + /* + * without IR all CPUs can be addressed by IOAPIC/MSI + * only in physical mode + */ + x2apic_force_phys(); + + } else if (ir_stat == IRQ_REMAP_XAPIC_MODE) { + pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n"); + return; + } + + if (!x2apic_mode) { + x2apic_mode = 1; + enable_x2apic(); + pr_info("Enabled x2apic\n"); + } #endif - return -1; } void __init enable_IR_x2apic(void) { unsigned long flags; - int ret; - int hardware_init_ret; + int ret, ir_stat; if (!IS_ENABLED(CONFIG_X86_X2APIC)) { u64 msr; @@ -1606,8 +1640,8 @@ void __init enable_IR_x2apic(void) panic("BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS.\n"); } - hardware_init_ret = irq_remapping_prepare(); - if (hardware_init_ret && !x2apic_supported()) + ir_stat = irq_remapping_prepare(); + if (ir_stat < 0 && !x2apic_supported()) return; ret = save_ioapic_entries(); @@ -1622,45 +1656,13 @@ void __init enable_IR_x2apic(void) if (x2apic_preenabled && nox2apic) disable_x2apic(); + /* If irq_remapping_prepare() succeded, try to enable it */ + if (ir_stat >= 0) + ir_stat = try_to_enable_IR(); + /* ir_stat contains the remap mode or an error code */ + try_to_enable_x2apic(ir_stat); - if (hardware_init_ret) - ret = -1; - else - ret = enable_IR(); - - if (!x2apic_supported()) - goto skip_x2apic; - - if (ret < 0) { - /* IR is required if there is APIC ID > 255 even when running - * under KVM - */ - if (max_physical_apicid > 255 || - !hypervisor_x2apic_available()) { - if (x2apic_preenabled) - disable_x2apic(); - goto skip_x2apic; - } - /* - * without IR all CPUs can be addressed by IOAPIC/MSI - * only in physical mode - */ - x2apic_force_phys(); - } - - if (ret == IRQ_REMAP_XAPIC_MODE) { - pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n"); - goto skip_x2apic; - } - - if (x2apic_supported() && !x2apic_mode) { - x2apic_mode = 1; - enable_x2apic(); - pr_info("Enabled x2apic\n"); - } - -skip_x2apic: - if (ret < 0) /* IR enabling failed */ + if (ir_stat < 0) restore_ioapic_entries(); legacy_pic->restore_mask(); local_irq_restore(flags); -- 2.34.1