Re: [Xen-devel] pvops-2.6.32 - Interrupt routing problem

[Bastian Blank <waldi@xxxxxxxxxx>]

On Tue, Mar 16, 2010 at 07:20:53PM +0100, Bastian Blank wrote:

Okay, lets go through the log again.

Initial readout before dom0 starts. Only 0 and 9 masked.

> (XEN)  NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect:   
> (XEN)  00 000 00  1    0    0   0   0    0    0    00
> (XEN)  01 000 00  0    0    0   0   0    0    0    28
> (XEN)  02 000 00  0    0    0   0   0    0    0    F0
> (XEN)  03 000 00  0    0    0   0   0    0    0    30
> (XEN)  04 000 00  0    0    0   0   0    0    0    F1
> (XEN)  05 000 00  0    0    0   0   0    0    0    38
> (XEN)  06 000 00  0    0    0   0   0    0    0    40
> (XEN)  07 000 00  0    0    0   0   0    0    0    48
> (XEN)  08 000 00  0    0    0   0   0    0    0    50
> (XEN)  09 000 00  1    1    0   1   0    0    0    58
> (XEN)  0a 000 00  0    0    0   0   0    0    0    60
> (XEN)  0b 000 00  0    0    0   0   0    0    0    68
> (XEN)  0c 000 00  0    0    0   0   0    0    0    70
> (XEN)  0d 000 00  0    0    0   0   0    0    0    78
> (XEN)  0e 000 00  0    0    0   0   0    0    0    88
> (XEN)  0f 000 00  0    0    0   0   0    0    0    90

Dom0 tries to set the first 16 IO-APIC pins to edge.

> (XEN) IOAPIC[0]: Set PCI routing entry (8-5 -> 0x38 -> IRQ 5 Mode:0 Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-6 -> 0x40 -> IRQ 6 Mode:0 Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-7 -> 0x48 -> IRQ 7 Mode:0 Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-8 -> 0x50 -> IRQ 8 Mode:0 Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-9 -> 0x58 -> IRQ 9 Mode:0 Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-10 -> 0x60 -> IRQ 10 Mode:0 
> Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-11 -> 0x68 -> IRQ 11 Mode:0 
> Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-12 -> 0x70 -> IRQ 12 Mode:0 
> Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-13 -> 0x78 -> IRQ 13 Mode:0 
> Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-14 -> 0x88 -> IRQ 14 Mode:0 
> Active:0)
> (XEN) IOAPIC[0]: Set PCI routing entry (8-15 -> 0x90 -> IRQ 15 Mode:0 
> Active:0)
> (XEN) Pin 8-9 already programmed

Dom0 have a console.

> [    0.000000] Linux version 2.6.32-4-xen-amd64 (Debian 2.6.32-10~xen.1) 
> (waldi@xxxxxxxxxx) (gcc version 4.3.4 (Debian 4.3.4-8) ) #1 SMP Tue Mar 16 
> 07:46:55 UTC 2010

ACPI only reports overrides for 2 and 9.

> [    0.000000] Already setup the GSI :0
> [    0.000000] Already setup the GSI :1
> [    0.000000] Already setup the GSI :2
> [    0.000000] Already setup the GSI :3
> [    0.000000] Already setup the GSI :4
> [    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 high edge)
> [    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)
> [    0.000000] xen: sci override: source_irq=9 global_irq=9 trigger=c 
> polarity=3
> [    0.000000] xen_allocate_pirq: returning irq 9 for gsi 9
> [    0.000000] Already setup the GSI :9
> [    0.000000] xen: acpi sci 9

Readout after dom0 booted. Several other pins masked, all set to edge.

> (XEN)  NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect:   
> (XEN)  00 000 00  1    0    0   0   0    0    0    00
> (XEN)  01 009 09  0    0    0   0   0    0    0    81
> (XEN)  02 000 00  0    0    0   0   0    0    0    F0
> (XEN)  03 000 00  0    0    0   0   0    0    0    30
> (XEN)  04 000 00  0    0    0   0   0    0    0    F1
> (XEN)  05 000 00  1    0    0   0   0    0    0    38
> (XEN)  06 000 00  1    0    0   0   0    0    0    40
> (XEN)  07 000 00  1    0    0   0   0    0    0    48
> (XEN)  08 009 09  0    0    0   0   0    0    0    89
> (XEN)  09 000 00  0    0    0   0   0    0    0    58
> (XEN)  0a 000 00  1    0    0   0   0    0    0    60
> (XEN)  0b 000 00  1    0    0   0   0    0    0    68
> (XEN)  0c 009 09  0    0    0   0   0    0    0    79
> (XEN)  0d 000 00  1    0    0   0   0    0    0    78
> (XEN)  0e 000 00  1    0    0   0   0    0    0    88
> (XEN)  0f 000 00  1    0    0   0   0    0    0    90

Load of driver which drives interrupt 14. It tries to reprogram it as
level driven.

> [   43.620022] xen_allocate_pirq: returning irq 14 for gsi 14
> (XEN) Pin 8-14 already programmed
> (XEN) IOAPIC[0]: Set PCI routing entry (8-14 -> 0x88 -> IRQ 14 Mode:1 
> Active:1)

Readout after.

> (XEN)  NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect:   
> (XEN)  00 000 00  1    0    0   0   0    0    0    00
> (XEN)  01 009 09  0    0    0   0   0    0    0    81
> (XEN)  02 000 00  0    0    0   0   0    0    0    F0
> (XEN)  03 000 00  0    0    0   0   0    0    0    30
> (XEN)  04 000 00  0    0    0   0   0    0    0    F1
> (XEN)  05 000 00  1    0    0   0   0    0    0    38
> (XEN)  06 000 00  1    0    0   0   0    0    0    40
> (XEN)  07 000 00  1    0    0   0   0    0    0    48
> (XEN)  08 009 09  0    0    0   0   0    0    0    89
> (XEN)  09 000 00  0    0    0   0   0    0    0    58
> (XEN)  0a 000 00  1    0    0   0   0    0    0    60
> (XEN)  0b 000 00  1    0    0   0   0    0    0    68
> (XEN)  0c 009 09  0    0    0   0   0    0    0    79
> (XEN)  0d 000 00  1    0    0   0   0    0    0    78
> (XEN)  0e 008 08  0    1    0   1   0    0    0    B2
> (XEN)  0f 000 00  1    0    0   0   0    0    0    90

I did some digging and found similar code that disallows
reprogramming of IO-APIC pins in
arch/x86/kernel/apic/io_apic.c:io_apic_set_pci_routing
So this behaviour is correct.

So the question is: Is it wrong for the kernel to do register_gsi calls
early in bootup for interrupts it does not know anything about?

Bastian

-- 
Even historians fail to learn from history -- they repeat the same mistakes.
                -- John Gill, "Patterns of Force", stardate 2534.7

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