From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp08.in.ibm.com (e28smtp08.in.ibm.com [122.248.162.8]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp08.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id E9F9D2C08AA for ; Wed, 26 Jun 2013 06:33:58 +1000 (EST) Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 26 Jun 2013 01:55:16 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 0BD851258051 for ; Wed, 26 Jun 2013 02:02:57 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5PKYBoP23724206 for ; Wed, 26 Jun 2013 02:04:12 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5PKXoYo005731 for ; Tue, 25 Jun 2013 20:33:52 GMT From: "Srivatsa S. Bhat" Subject: [PATCH v2 28/45] KVM: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com Date: Wed, 26 Jun 2013 02:00:36 +0530 Message-ID: <20130625203036.16593.50377.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> References: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, Gleb Natapov , nikunj@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, wangyun@linux.vnet.ibm.com, "Srivatsa S. Bhat" , netdev@vger.kernel.org, Paolo Bonzini , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Gleb Natapov Cc: Paolo Bonzini Cc: kvm@vger.kernel.org Signed-off-by: Srivatsa S. Bhat --- virt/kvm/kvm_main.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 302681c..5bbfa30 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -174,7 +174,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req) zalloc_cpumask_var(&cpus, GFP_ATOMIC); - me = get_cpu(); + me = get_online_cpus_atomic(); kvm_for_each_vcpu(i, vcpu, kvm) { kvm_make_request(req, vcpu); cpu = vcpu->cpu; @@ -192,7 +192,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req) smp_call_function_many(cpus, ack_flush, NULL, 1); else called = false; - put_cpu(); + put_online_cpus_atomic(); free_cpumask_var(cpus); return called; } @@ -1707,11 +1707,11 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu) ++vcpu->stat.halt_wakeup; } - me = get_cpu(); + me = get_online_cpus_atomic(); if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) if (kvm_arch_vcpu_should_kick(vcpu)) smp_send_reschedule(cpu); - put_cpu(); + put_online_cpus_atomic(); } EXPORT_SYMBOL_GPL(kvm_vcpu_kick); #endif /* !CONFIG_S390 */