From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758833Ab3D2SfC (ORCPT ); Mon, 29 Apr 2013 14:35:02 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:24760 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758372Ab3D2SfA (ORCPT ); Mon, 29 Apr 2013 14:35:00 -0400 Date: Mon, 29 Apr 2013 14:34:50 -0400 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" Subject: Re: [PATCH 7/9] xen/spinlock: Disable IRQ spinlock (PV) allocation on PVHVM Message-ID: <20130429183450.GB9431@phenom.dumpdata.com> References: <1366142947-18655-1-git-send-email-konrad.wilk@oracle.com> <1366142947-18655-8-git-send-email-konrad.wilk@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) 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 Fri, Apr 26, 2013 at 05:20:23PM +0100, Stefano Stabellini wrote: > On Tue, 16 Apr 2013, Konrad Rzeszutek Wilk wrote: > > See git commit f10cd522c5fbfec9ae3cc01967868c9c2401ed23 > > (xen: disable PV spinlocks on HVM) for details. > > > > But we did not disable it everywhere - which means that when > > we boot as PVHVM we end up allocating per-CPU irq line for > > spinlock. This fixes that. > > > > Signed-off-by: Konrad Rzeszutek Wilk > > Is there any point in calling xen_init_lock_cpu in PVHVM guests? I was thinking about it.. but I still have hope that I will be able to take Jeremy's patches for paravirt locking and redo them a bit. > At that point we might as well remove the call from xen_hvm_cpu_notify. > > > > arch/x86/xen/spinlock.c | 21 +++++++++++++++++++++ > > 1 file changed, 21 insertions(+) > > > > diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c > > index 47ae032..8b54603 100644 > > --- a/arch/x86/xen/spinlock.c > > +++ b/arch/x86/xen/spinlock.c > > @@ -367,6 +367,13 @@ void __cpuinit xen_init_lock_cpu(int cpu) > > WARN(per_cpu(lock_kicker_irq, cpu) > 0, "spinlock on CPU%d exists on IRQ%d!\n", > > cpu, per_cpu(lock_kicker_irq, cpu)); > > > > + /* > > + * See git commit f10cd522c5fbfec9ae3cc01967868c9c2401ed23 > > + * (xen: disable PV spinlocks on HVM) > > + */ > > + if (xen_hvm_domain()) > > + return; > > + > > name = kasprintf(GFP_KERNEL, "spinlock%d", cpu); > > irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR, > > cpu, > > @@ -385,12 +392,26 @@ void __cpuinit xen_init_lock_cpu(int cpu) > > > > void xen_uninit_lock_cpu(int cpu) > > { > > + /* > > + * See git commit f10cd522c5fbfec9ae3cc01967868c9c2401ed23 > > + * (xen: disable PV spinlocks on HVM) > > + */ > > + if (xen_hvm_domain()) > > + return; > > + > > unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL); > > per_cpu(lock_kicker_irq, cpu) = -1; > > } > > > > void __init xen_init_spinlocks(void) > > { > > + /* > > + * See git commit f10cd522c5fbfec9ae3cc01967868c9c2401ed23 > > + * (xen: disable PV spinlocks on HVM) > > + */ > > + if (xen_hvm_domain()) > > + return; > > + > > BUILD_BUG_ON(sizeof(struct xen_spinlock) > sizeof(arch_spinlock_t)); > > > > pv_lock_ops.spin_is_locked = xen_spin_is_locked; > > -- > > 1.8.1.4 > >