From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH v7 1/4] KVM: x86: Split the APIC from the rest of IRQCHIP. Date: Fri, 31 Jul 2015 10:32:54 +0200 Message-ID: <55BB32B6.4040109@siemens.com> References: <1438237303-19124-1-git-send-email-srutherford@google.com> <55B9DEA2.1070304@redhat.com> <20150730083739.GB19524@google.com> <55B9F08C.6080604@redhat.com> <20150730211925.GA28478@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Steve Rutherford , Paolo Bonzini Return-path: Received: from david.siemens.de ([192.35.17.14]:42980 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751410AbbGaIdC (ORCPT ); Fri, 31 Jul 2015 04:33:02 -0400 In-Reply-To: <20150730211925.GA28478@google.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2015-07-30 23:19, Steve Rutherford wrote: > On Thu, Jul 30, 2015 at 11:38:20AM +0200, Paolo Bonzini wrote: >> >> >> On 30/07/2015 10:37, Steve Rutherford wrote: >>> This looks a bit non-sensical, but is overprepared for the introduction >>> IOAPIC hotplug, which two patches down the line. Changing it is fine, >>> you'll just need to merge the very same change back. >> >> By "IOAPIC hotplug" you mean changing the number of reserved routes? Is >> it necessary? You could just reserve a bunch of routes depending on the >> maximum number of IOAPICs. > Hmm. Yeah, I think that might be cleaner. Thinking about it, I'm a bit nervous > about the idea of the number of reserved routes shrinking. We would have needed > to trigger an IOAPIC scan if the number of reserved routes changed. > > Jan might have an opinion here. A static preallocation is likely fine, given reasonable room. I have no idea about a good limit, though. To be safe, we could pull in someone from Intel, maybe the guy who worked on the IOAPIC refactorings in the kernel to enable hotplugging. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux