Zachary Amsden wrote:
Anthony Liguori wrote:
Hi Zach,
It seems to me that the APIC paravirt_ops should be filled by
para_fill() instead of vmi_get_function(). vmi_get_function()
returns a nop when the relocation type is NONE. para_fill() leaves
the native code in place.
The native version of the apic write ops is more or less *(APIC_BASE
+ reg) = value. APIC_BASE is unknown to the ROM so it's impossible
to simulate this in the ROM.
This means that a ROM has no choice but to do APIC emulation (or jump
through seriously hairy loops to get the APIC mapped in it's address
space). Was this the intention?
No, but certainly the effect. Actually, it is very easy to get the
APIC mapped in the ROM address space without jumping through seriously
hairy loops - we do it today in our hypervisor.
I neglected to mention that I didn't want to use a memory hole. One
could allocate a small one to map the APIC but that seems to defeat the
purpose of having a native ROM.
Regards,
Anthony Liguori
N.B. attached patch is just to illustrate the point. Has not even
been compile tested.
Patch looks good, thanks. But the whole para_fill / vmi_get_function
stuff could probably be done even cleaner. It was just a helper at
first to work around the awkward syntax, and it is still a bit ugly,
but I haven't come up with a better solution yet, mostly because with
the new inlining work Jeremy is doing, we might want to start doing
selective inlining, in which case I'll have to go back over the code
anyway to clean everything to get the logic right in all cases.
I assume this patch is signed-off-by you? If so, I'll add it to my
patch queue.
Zach
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
