From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/8] use jump labels to streamline common APIC configuration Date: Tue, 14 Aug 2012 17:04:16 +0300 Message-ID: <502A5AE0.3080608@redhat.com> References: <1344171513-4659-1-git-send-email-gleb@redhat.com> <501E760E.9050109@redhat.com> <20120805133549.GL27579@redhat.com> <501E7839.2030008@redhat.com> <20120805134842.GM27579@redhat.com> <501E7C85.70001@redhat.com> <20120805140305.GN27579@redhat.com> <502A5A16.6040506@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , "kvm@vger.kernel.org" , "mtosatti@redhat.com" To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:22088 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751663Ab2HNOEU (ORCPT ); Tue, 14 Aug 2012 10:04:20 -0400 In-Reply-To: <502A5A16.6040506@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/14/2012 05:00 PM, Jan Kiszka wrote: >>> The host can prevent this by leaving disabling the guest pmu. But >>> disabling jump labels for real-time kernels may be acceptable too. We >>> can probably to it at run time by forcing the slow path at all times. >> Yes, it is possible to add module option that will force slow path if >> needed. > > Should I write a patch or will you? Having host-side stop_machine due to > such common guest operations is indeed a no-go for RT. > Note that an additional patch is needed for perf, otherwise the guest (or a user, but that's less of a concern for realtime) can easily invoke stop_machine by configuring and unconfiguring its pmu. -- error compiling committee.c: too many arguments to function