From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752161AbdGDK1v (ORCPT ); Tue, 4 Jul 2017 06:27:51 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:49013 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845AbdGDK1t (ORCPT ); Tue, 4 Jul 2017 06:27:49 -0400 Date: Tue, 4 Jul 2017 12:27:43 +0200 From: Claudio Imbrenda To: Paolo Bonzini Cc: kvm@vger.kernel.org, borntraeger@de.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 1/1] KVM: trigger uevents when starting or stopping a VM In-Reply-To: <8d239a6c-3625-6964-7fd2-b753f2e15bf5@redhat.com> References: <1499159018-19782-1-git-send-email-imbrenda@linux.vnet.ibm.com> <8d239a6c-3625-6964-7fd2-b753f2e15bf5@redhat.com> Organization: IBM X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 17070410-0040-0000-0000-000003BAF2FE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17070410-0041-0000-0000-000025B55195 Message-Id: <20170704122743.395fbf97@p-imbrenda.boeblingen.de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-04_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1707040180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 4 Jul 2017 11:23:36 +0200 Paolo Bonzini wrote: > On 04/07/2017 11:03, Claudio Imbrenda wrote: > > This patch adds a few lines to the KVM common code to fire a > > KOBJ_CHANGE uevent whenever a KVM VM is created or destroyed. The > > event carries two environment variables: > > KVM_VM_CREATED which indicates how many times a new VM has been > > created, KVM_VM_COUNT which indicates how many VMs are currently > > active. > > I'm not sure why KVM_VM_CREATED is useful, KVM_VM_COUNT can be a bit > more interesting though not much. > > But since we are at it, let's also add a PID. That one is the really > useful one, because it gives you something to look at in debugfs. > Another possibility is to add the debugfs directory name directly > (KVM_VM_STATS_PATH or something like that). I'll add those > Paolo > > > Specific udev rules can be then set up in userspace to deal with the > > creation or destruction of VMs as needed. > > > > Signed-off-by: Claudio Imbrenda > > --- > > virt/kvm/kvm_main.c | 25 +++++++++++++++++++++++++ > > 1 file changed, 25 insertions(+) > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index 6e3b12c..f67aa59 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -130,6 +130,10 @@ EXPORT_SYMBOL_GPL(kvm_rebooting); > > > > static bool largepages_enabled = true; > > > > +static void kvm_uevent_notify_change(u64 created, u64 active); > > +static u64 kvm_createvm_count; > > +static u64 kvm_active_vms; > > + > > bool kvm_is_reserved_pfn(kvm_pfn_t pfn) > > { > > if (pfn_valid(pfn)) > > @@ -627,6 +631,7 @@ static struct kvm *kvm_create_vm(unsigned long > > type) { > > int r, i; > > struct kvm *kvm = kvm_arch_alloc_vm(); > > + u64 activevms, createdvms; > > > > if (!kvm) > > return ERR_PTR(-ENOMEM); > > @@ -686,9 +691,12 @@ static struct kvm *kvm_create_vm(unsigned long > > type) > > spin_lock(&kvm_lock); > > list_add(&kvm->vm_list, &vm_list); > > + createdvms = ++kvm_createvm_count; > > + activevms = ++kvm_active_vms; > > spin_unlock(&kvm_lock); > > > > preempt_notifier_inc(); > > + kvm_uevent_notify_change(createdvms, activevms); > > > > return kvm; > > > > @@ -739,11 +747,14 @@ static void kvm_destroy_vm(struct kvm *kvm) > > { > > int i; > > struct mm_struct *mm = kvm->mm; > > + u64 activevms, createdvms; > > > > kvm_destroy_vm_debugfs(kvm); > > kvm_arch_sync_events(kvm); > > spin_lock(&kvm_lock); > > list_del(&kvm->vm_list); > > + activevms = --kvm_active_vms; > > + createdvms = kvm_createvm_count; > > spin_unlock(&kvm_lock); > > kvm_free_irq_routing(kvm); > > for (i = 0; i < KVM_NR_BUSES; i++) { > > @@ -767,6 +778,7 @@ static void kvm_destroy_vm(struct kvm *kvm) > > preempt_notifier_dec(); > > hardware_disable_all(); > > mmdrop(mm); > > + kvm_uevent_notify_change(createdvms, activevms); > > } > > > > void kvm_get_kvm(struct kvm *kvm) > > @@ -3864,6 +3876,19 @@ static const struct file_operations > > *stat_fops[] = { [KVM_STAT_VM] = &vm_stat_fops, > > }; > > > > +static void kvm_uevent_notify_change(u64 created, u64 active) > > +{ > > + char createvm_buf[40]; > > + char activevm_buf[40]; > > + char *ptr[3] = {createvm_buf, activevm_buf, NULL}; > > + > > + if (!kvm_dev.this_device) > > + return; > > + snprintf(createvm_buf, 40, "KVM_VM_CREATED=%llu", created); > > + snprintf(activevm_buf, 40, "KVM_VM_ACTIVE=%llu", active); > > + kobject_uevent_env(&kvm_dev.this_device->kobj, > > KOBJ_CHANGE, ptr); +} > > + > > static int kvm_init_debug(void) > > { > > int r = -EEXIST; > > >