Jeremy Fitzhardinge <jeremy@xxxxxxxx> writes:
> Parse the ACPI MADT for I/O APIC information, even if the cpu has no
> (apparent) local APIC (ie, the CPU's APIC feature flag is clear).
>
> In principle, the local APIC and the I/O APIC are distinct (but related)
> components, which can be independently present.
>
> In practice this can happen in a Xen system, where the hypervisor has
> full control over the local APICs, and delivers interrupts initiated by
> the I/O APICs via Xen's event channel mechanism.
>
> (This eliminates the need for any explicit if (xen...) tests in
> acpi/boot.c)
>
> Signed-off-by: Jeremy Fitzhardinge<jeremy.fitzhardinge@xxxxxxxxxx>
To be very clear. We have mechanism and policy mixed in the mptable
and related code today. While we continue to have that mixed I think
even attempting to reuse it for Xen dom0 is a horrifically bad move.
Nacked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
> index 2410469..19d13e5 100644
> --- a/arch/x86/kernel/acpi/boot.c
> +++ b/arch/x86/kernel/acpi/boot.c
> @@ -193,9 +193,6 @@ static int __init acpi_parse_madt(struct
> acpi_table_header *table)
> {
> struct acpi_table_madt *madt = NULL;
>
> - if (!cpu_has_apic)
> - return -EINVAL;
> -
> madt = (struct acpi_table_madt *)table;
> if (!madt) {
> printk(KERN_WARNING PREFIX "Unable to map MADT\n");
> @@ -1252,9 +1249,6 @@ static int __init acpi_parse_madt_ioapic_entries(void)
> if (acpi_disabled || acpi_noirq)
> return -ENODEV;
>
> - if (!cpu_has_apic)
> - return -ENODEV;
> -
> /*
> * if "noapic" boot option, don't look for IO-APICs
> */
> @@ -1357,6 +1351,16 @@ static void __init acpi_process_madt(void)
> #ifdef CONFIG_X86_BIGSMP
> generic_bigsmp_probe();
> #endif
> + }
> + if (error == -EINVAL) {
> + /*
> + * The ACPI tables themselves were malformed.
> + * Dell Precision Workstation 410, 610 come here.
> + */
> + printk(KERN_ERR PREFIX
> + "Invalid BIOS MADT, disabling ACPI\n");
> + disable_acpi();
> + } else {
> /*
> * Parse MADT IO-APIC entries
> */
> @@ -1370,14 +1374,6 @@ static void __init acpi_process_madt(void)
> apic->setup_apic_routing();
> }
> }
> - if (error == -EINVAL) {
> - /*
> - * Dell Precision Workstation 410, 610 come here.
> - */
> - printk(KERN_ERR PREFIX
> - "Invalid BIOS MADT, disabling ACPI\n");
> - disable_acpi();
> - }
> } else {
> /*
> * ACPI found no MADT, and so ACPI wants UP PIC mode.
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index c6acce2..d5e3f03 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -1807,6 +1807,10 @@ __apicdebuginit(void) print_all_local_APICs(void)
> {
> int cpu;
>
> + /* don't print out if apic is not there */
> + if (!cpu_has_apic)
> + return;
> +
> preempt_disable();
> for_each_online_cpu(cpu)
> smp_call_function_single(cpu, print_local_APIC, NULL, 1);
> @@ -1849,8 +1853,7 @@ __apicdebuginit(int) print_all_ICs(void)
> {
> print_PIC();
>
> - /* don't print out if apic is not there */
> - if (!cpu_has_apic || disable_apic)
> + if (disable_apic)
> return 0;
>
> print_all_local_APICs();
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