Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756535Ab0BXK3K (ORCPT ); Wed, 24 Feb 2010 05:29:10 -0500 Received: from thoth.sbs.de ([192.35.17.2]:21286 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756471Ab0BXK3H (ORCPT ); Wed, 24 Feb 2010 05:29:07 -0500 Message-ID: <4B84FF5C.5090603@siemens.com> Date: Wed, 24 Feb 2010 11:28:44 +0100 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Avi Kivity CC: Thomas Gleixner , KVM , Gleb Natapov , RT , Linux Kernel Mailing List Subject: Re: [PATCH] KVM: x86: Kick VCPU outside PIC lock again References: <20100217135901.331576359@linutronix.de> <4B842A1F.50601@siemens.com> <4B84F466.2080009@siemens.com> <4B84F5D4.5020202@redhat.com> <4B84F765.5040209@siemens.com> <4B84F9AF.8060804@redhat.com> <4B84FBDB.1070006@siemens.com> <4B84FCBB.8070702@redhat.com> <4B84FDF5.5080106@siemens.com> In-Reply-To: <4B84FDF5.5080106@siemens.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1130 Lines: 33 Jan Kiszka wrote: > Avi Kivity wrote: >> On 02/24/2010 12:13 PM, Jan Kiszka wrote: >>> >>>> I see. Won't we hit the same issue when we call pic functions from >>>> atomic context during the guest entry sequence? >>>> >>>> >>> If there are such call paths, for sure. What concrete path(s) do you >>> have in mind? >>> >>> >> vcpu_enter_guest() -> inject_pending_event() -> >> kvm_cpu_{has,get}_interrupt() -> various pic functions if you're unlucky. > > But do they kick anyone or just check/pull information? Never saw any > warnings during my tests last year (granted: with older -rt and kvm > versions). Mmh, they could if there is > 1 IRQ pending. Guess this just never triggered in real life due to typical APIC use and low IRQ load during PIC times in my tests. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/