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SubjectRe: [RESEND PATCH 3/3] x86/apic: Clean up the names of legacy irq mode setting related functions
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Hi Baoquan,

At 01/05/2018 12:39 PM, Baoquan He wrote:
[...]
> /*
> - * Not an __init, needed by kexec/kdump code.
> - * For safety IO-APIC and Local APIC need be cleared before this.
> + * In legacy irq mode, full DOS compatibility with the uniprocessor PC/AT is
> + * provided by using the APICs in conjunction with standard 8259A-equivalent
> + * programmable interrupt controllers (PICs). It's necessary to deliver legacy
> + * interrupts even when APIC mode is not enabled. This is required by kexec/
> + * kdump before enter into the 2nd kernel.
> */
> void switch_to_legacy_irq_mode(void)
> {
> if (!nr_legacy_irqs())
> return;
>
> - x86_io_apic_ops.disable();
> + ioapic_set_virtual_wire_mode();
> +
> + if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
> + lapic_set_legacy_irq_mode(ioapic_i8259.pin != -1);

Seems these two function, ioapic/lapic_set_legacy_irq_mode should be
exclusive.

But We do that because both the through-lapic and through-ioapic virtual
wire mode need setup the APIC_SPIV_APIC_ENABLED which is only located in
the lapic_set_legacy_irq_mode(). So we need call them both.

IMO, this cleanup may not make it clear. we can separate these two mode
totally or just keep it like before.

Thanks,
dou.
> }
>
> #ifdef CONFIG_X86_32
> diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
> index 1151ccd72ce9..c30f0f273dbd 100644
> --- a/arch/x86/kernel/x86_init.c
> +++ b/arch/x86/kernel/x86_init.c
> @@ -148,5 +148,5 @@ void arch_restore_msi_irqs(struct pci_dev *dev)
>
> struct x86_io_apic_ops x86_io_apic_ops __ro_after_init = {
> .read = native_io_apic_read,
> - .disable = native_disable_io_apic,
> + .disable = switch_to_legacy_irq_mode,
> };
> diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
> index 49721b4e1975..751472ddf536 100644
> --- a/drivers/iommu/irq_remapping.c
> +++ b/drivers/iommu/irq_remapping.c
> @@ -37,7 +37,7 @@ static void irq_remapping_disable_io_apic(void)
> * now.
> */
> if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
> - disconnect_bsp_APIC(0);
> + lapic_set_legacy_irq_mode(0);
> }
>
> static void __init irq_remapping_modify_x86_ops(void)
>


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