Re: [GIT PULL] Xen APIC hooks (with io_apic_ops)
From: Avi Kivity
Date: Mon May 25 2009 - 00:56:43 EST
Ingo Molnar wrote:
We do something similar for Windows (by patching it) very
successfully; Windows likes to touch the APIC TPR ~ 100,000 times
per second, usually without triggering an interrupt. We hijack
these writes, do the checks in guest context, and only exit if the
TPR write would trigger an interrupt.
I suspect you aware of that this is about the io-apic not the local
APIC. The local apic methods are already driver-ized - and they sit
closer to the CPU so they matter more to performance.
Yeah, I gave this as an example. It's very different -- io-apic vs.
local apic, paravirtualization vs. patching the guest behind its back,
Linux vs. Windows.
Of course if we hook the io-apic EOI we'll want to hook the local apic
EOI as well.
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
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