Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753895AbaKYMPs (ORCPT ); Tue, 25 Nov 2014 07:15:48 -0500 Received: from smtp.citrix.com ([66.165.176.89]:44818 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753813AbaKYMPp (ORCPT ); Tue, 25 Nov 2014 07:15:45 -0500 X-IronPort-AV: E=Sophos;i="5.07,455,1413244800"; d="scan'208";a="196103401" Date: Tue, 25 Nov 2014 12:06:35 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Boris Ostrovsky CC: , , , , , Subject: Re: [PATCH v3 1/2] xen/pci: Defer initialization of MSI ops on HVM guests until after x2APIC has been set up In-Reply-To: <1416870378-32481-2-git-send-email-boris.ostrovsky@oracle.com> Message-ID: References: <1416870378-32481-1-git-send-email-boris.ostrovsky@oracle.com> <1416870378-32481-2-git-send-email-boris.ostrovsky@oracle.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? > Signed-off-by: Boris Ostrovsky > --- > arch/x86/pci/xen.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c > index 093f5f4..1370716 100644 > --- a/arch/x86/pci/xen.c > +++ b/arch/x86/pci/xen.c > @@ -431,6 +431,14 @@ int __init pci_xen_init(void) > return 0; > } > > +#ifdef CONFIG_PCI_MSI > +void __init xen_msi_init(void) > +{ > + x86_msi.setup_msi_irqs = xen_hvm_setup_msi_irqs; > + x86_msi.teardown_msi_irq = xen_teardown_msi_irq; > +} > +#endif > + > int __init pci_xen_hvm_init(void) > { > if (!xen_have_vector_callback || !xen_feature(XENFEAT_hvm_pirqs)) > @@ -445,8 +453,11 @@ int __init pci_xen_hvm_init(void) > #endif > > #ifdef CONFIG_PCI_MSI > - x86_msi.setup_msi_irqs = xen_hvm_setup_msi_irqs; > - x86_msi.teardown_msi_irq = xen_teardown_msi_irq; > + /* > + * We need to wait until after x2apic is initialized > + * before we can set MSI IRQ ops. > + */ > + x86_platform.apic_post_init = xen_msi_init; > #endif > return 0; > } > -- > 1.9.3 > -- 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/