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Re: [Xen-devel] APIC handling on x86-64

On 20 Mar 2006, at 13:53, Jan Beulich wrote:

Hmm, I'm not sure. Both because it wouldn't address all issues (the
I/O APIC redirection table entries also need to be programmed in
physical mode) and because I'm not so certain about legacy 32-bit
issues (on 32-bits you still have to account for the PentiumPro/II/III
behavior, namely the only 4-bit wide IDs, as that at least seems to
imply different cut-off criteria for the decision what destination mode
to use).

We can just steal x86/64 phys cluster code for summit. ES7000 already has its own phys cluster code that doesn't look like it will have this issue, Bigsmp uses phys flat, and Default uses logical flat. So summit is the only subarch that needs fixing.

Xen's io_apic.c will program logical/phys dest mode appropriately (although it's taken from i386 io_apic.c, those parts of the i386 file are identical to x86/64 io_apic.c).

I'd also like to fix send_IPI_mask_sequence() to use physical destination mode. It scares me a bit that 2.6.16 native i386 bigsmp mode uses physical flat model, but uses send_IPI_mask_sequence with logical delivery. Seems weird to me.

Both this and the summit fix will be after 3.0.2 now.

 -- Keir

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