From: Michael S. Tsirkin Date: Sun, 24 Jun 2012 16:25:07 +0000 (+0300) Subject: KVM: host side for eoi optimization X-Git-Tag: v3.6-rc1~124^2~55 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ae7a2a3fb6f8b784c2752863f4f1f20c656f76fb;p=pandora-kernel.git KVM: host side for eoi optimization Implementation of PV EOI using shared memory. This reduces the number of exits an interrupt causes as much as by half. The idea is simple: there's a bit, per APIC, in guest memory, that tells the guest that it does not need EOI. We set it before injecting an interrupt and clear before injecting a nested one. Guest tests it using a test and clear operation - this is necessary so that host can detect interrupt nesting - and if set, it can skip the EOI MSR. There's a new MSR to set the address of said register in guest memory. Otherwise not much changed: - Guest EOI is not required - Register is tested & ISR is automatically cleared on exit For testing results see description of previous patch 'kvm_para: guest side for eoi avoidance'. Signed-off-by: Michael S. Tsirkin Signed-off-by: Avi Kivity --- Reading git-diff-tree failed