Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751238AbaKYPI7 (ORCPT ); Tue, 25 Nov 2014 10:08:59 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:48107 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750964AbaKYPI6 (ORCPT ); Tue, 25 Nov 2014 10:08:58 -0500 Message-ID: <54749C2B.4090303@oracle.com> Date: Tue, 25 Nov 2014 10:11:39 -0500 From: Boris Ostrovsky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Stefano Stabellini CC: david.vrabel@citrix.com, konrad.wilk@oracle.com, jun.nakajima@intel.com, linux-kernel@vger.kernel.org, xen-devel@lists.xen.org Subject: Re: [PATCH v3 1/2] xen/pci: Defer initialization of MSI ops on HVM guests until after x2APIC has been set up References: <1416870378-32481-1-git-send-email-boris.ostrovsky@oracle.com> <1416870378-32481-2-git-send-email-boris.ostrovsky@oracle.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/25/2014 07:06 AM, Stefano Stabellini wrote: > On Mon, 24 Nov 2014, Boris Ostrovsky wrote: >> If the hardware supports APIC virtualization we may decide not to use pirqs >> and instead use APIC/x2APIC directly, meaning that we don't want to set >> x86_msi.setup_msi_irqs and x86_msi.teardown_msi_irq to Xen-specific routines. >> However, x2APIC is not set up by the time pci_xen_hvm_init() is called so we >> need to postpone setting these ops until later, when we know which APIC mode >> is used. >> >> (Note that currently x2APIC is never initialized on HVM guests. This may >> change in the future) > I take that this is safe because no MSIs can be received at this point > (apic_post_init), right? Yes. At the time apic_post_init() is called PCI has not been probed yet. -boris -- 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/