From: Marcelo Tosatti Date: Wed, 24 Sep 2008 23:28:34 +0000 (-0300) Subject: KVM: PIC: enhance IPI avoidance X-Git-Tag: v2.6.28-rc1~269^2~11 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e48258009d941891fca35348986b8d280caf31cd;p=pandora-kernel.git KVM: PIC: enhance IPI avoidance The PIC code makes little effort to avoid kvm_vcpu_kick(), resulting in unnecessary guest exits in some conditions. For example, if the timer interrupt is routed through the IOAPIC, IRR for IRQ 0 will get set but not cleared, since the APIC is handling the acks. This means that everytime an interrupt < 16 is triggered, the priority logic will find IRQ0 pending and send an IPI to vcpu0 (in case IRQ0 is not masked, which is Linux's case). Introduce a new variable isr_ack to represent the IRQ's for which the guest has been signalled / cleared the ISR. Use it to avoid more than one IPI per trigger-ack cycle, in addition to the avoidance when ISR is set in get_priority(). Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- Reading git-diff-tree failed