From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: FW: [kvm-commits] KVM: Move interrupt injection out of interruptdisabled section Date: Wed, 17 Oct 2007 17:42:44 +0200 Message-ID: <47162D74.6010408@qumranet.com> References: <10EA09EFD8728347A513008B6B0DA77A023EF364@pdsmsx411.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: "Dong, Eddie" Return-path: In-Reply-To: <10EA09EFD8728347A513008B6B0DA77A023EF364-wq7ZOvIWXbNpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dong, Eddie wrote: > Wrong mailing list. > Resend :-( > > (and here's a copy of my reply if someone is interested) > Dong, Eddie wrote: > >> Avi: >> This patch may be questionable at least for current VMX. >> If VM_ENTRY_INTR_INFO_FIELD is already set valid by >> previous irq injection, next injection will be refused with IRQ window >> enabled. This is because current implementation will inject exception >> earlier than irq injection and vmx_intr_assist doesn;t know if >> previous injected event is external irq (and thus overwrite) or >> exception. Guest will see lower priority irq get injected rather than >> higher >> priority IRQ which >> arrives later. >> >> Well, the same thing happens with the code before this commit, no? If a high priority interrupt arrives after injection, it will have to wait. The difference is that before this commit, it woke up with the IPI and now it notices with KVM_REQ_INTR. The window grew larger, but not by much typically. >> BTW, I didn't see obvious benfit from this patch since >> inject_pending_irq still happens later after IRQ disable. maybe I >> miss something. >> >> That was accidental; I corrected it. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/