Messages in this thread | | | Date | Mon, 23 Apr 2012 11:11:23 -0400 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [Xen-devel] [PATCH] xen/apic: implement io apic read with hypercall |
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> >> > How about return -1 on error? > >> > The calling function can check -1 for error. > >> > >> Isn't -1 potentially (at least theoretically) a valid value to read from > >> one of these registers? > > > > Yeah, but then we are back to crashing at bootup (with dom0) :-) > > > > Perhaps the fallback is to emulate (so retain some of the original code) > > as we have been since .. uh 3.0? > > Do you mean the return value of io_apic_read in 3.0?
No. I meant that we would continue to emulate. The improvement is that now we do:
if (reg == 0x1) return 0x00170020; else if (reg == 0x0) return apic << 24;
instead of 0xfdfdfdfd.
> It's 0xffffffff.
Now it is 0xfdfdfdfd.
I am suggesting that instead of BUG_ON(), we fallback to do returning an emulatated IO_APIC values - like the ones that this original patch cooked up.. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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