From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raghavendra K T Subject: Re: [PATCH] kvm fix: Enable pvspinlock after jump_label_init() to avoid VM hang Date: Sun, 13 Oct 2013 13:38:57 +0530 Message-ID: <525A5519.2050205@linux.vnet.ibm.com> References: <1381309401-23663-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Raghavendra K T , x86@kernel.org, gleb@redhat.com, pbonzini@redhat.com, konrad.wilk@oracle.com, habanero@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mtosatti@redhat.com, Steven Rostedt To: mingo@redhat.com, hpa@zytor.com, tglx@linutronix.de Return-path: In-Reply-To: <1381309401-23663-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 10/09/2013 02:33 PM, Raghavendra K T wrote: > We use jump label to enable pv-spinlock. With the changes in > (442e0973e927 Merge branch 'x86/jumplabel'), the jump label behaviour has changed > that would result in evntual hang of the VM since we would end up in a situation > where slowpath locks would halt the vcpus but we will not be able to wakeup the > vcpu by lock releaser using unlock kick. > > Similar problem in Xen and more detailed description is available in > a945928ea270 (xen: Do not enable spinlocks before jump_label_init() has executed) > > This patch splits kvm_spinlock_init to separate jump label changes with pvops > patching and also make jump label enabling after jump_label_init(). > > Signed-off-by: Raghavendra K T Ingo, Could you please take this fix? This is reviewed by Paolo and Steven.