Re: [Xen-devel] Xen-unstable boot panic due to changeset 26517 AMD, IOMMU: Clean up old entries in remapping tables when creating new one

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.02.13 at 21:14, Suravee Suthikulanit <suravee.suthikulpanit@xxxxxxx> 
>>> wrote:
> CASE1: BIOS disable the IOAPIC in the southbridge (SB8X0 chipset)
> This is the case we are seeing here with the AMD 890-FX motherboard.
> Here, the MADT is reporting 2 IOAPICs as shown by the message:
> 
> (XEN) ACPI: IOAPIC (id[0x06] address[0xfec00000] gsi_base[0])
> (XEN) IOAPIC[0]: apic_id 6, version 33, address 0xfec00000, GSI 0-23
> (XEN) ACPI: IOAPIC (id[0x07] address[0xfec20000] gsi_base[24])
> (XEN) IOAPIC[1]: apic_id 7, version 33, address 0xfec20000, GSI 24-55
> 
> However, when Xen tries to setup the IOMMU interrupt remapping table using 
> IVHD
> entries, there is only one IOAPIC (IOAPIC 1 with apic_id 7).
> 
> (XEN) AMD-Vi: IVHD Device Entry: type 0x48 id 0 flags 0
> (XEN) AMD-Vi: IVHD Special: 0000:00:00.1 variety 0x1 handle 0x7
> (XEN) IVHD Error: no information for IO-APIC 0x6
> (XEN) AMD-Vi: Error initialization

But you realize that it's the _first_ IO-APIC that has no
representation in IVRS? And it can only reasonably be the 2nd
that the BIOS might choose to disable (or else legacy interrupts,
including the timer, wouldn't work).

> In this case, if we should be able to look at the IVHD to correlate IOAPIC 
> ID (0 or 1)
> from the "handle" field and map it back to the BDF to setup the remapping 
> table.

I don't currently see how you would figure out the BDF for the
IO-APIC. Care to explain?

Jan


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