| Message ID | 1499159018-19782-1-git-send-email-imbrenda@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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). 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 <imbrenda@linux.vnet.ibm.com> > --- > 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; >
On 07/04/2017 11:23 AM, 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. I am certainly interested in an trigger from "kvm was never used" to "kvm was used", so having something like KVM_VM_CREATED has a value for me. > > 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). > > 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 <imbrenda@linux.vnet.ibm.com> >> --- >> 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; >> >
On 04/07/2017 11:25, Christian Borntraeger wrote: > On 07/04/2017 11:23 AM, 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. > > I am certainly interested in an trigger from "kvm was never used" to "kvm was used", > so having something like KVM_VM_CREATED has a value for me. Fair enough, that's a good use. Please add it to the commit message, however. Paolo >> 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). >> >> 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 <imbrenda@linux.vnet.ibm.com> >>> --- >>> 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; >>> >> >
On Tue, 4 Jul 2017 11:23:36 +0200 Paolo Bonzini <pbonzini@redhat.com> 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 <imbrenda@linux.vnet.ibm.com> > > --- > > 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; > > >
On Tue, 4 Jul 2017 11:27:44 +0200 Paolo Bonzini <pbonzini@redhat.com> wrote: > On 04/07/2017 11:25, Christian Borntraeger wrote: > > On 07/04/2017 11:23 AM, 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. > > > > I am certainly interested in an trigger from "kvm was never used" > > to "kvm was used", so having something like KVM_VM_CREATED has a > > value for me. > > Fair enough, that's a good use. Please add it to the commit message, > however. I'll add that too > Paolo > > >> 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). > >> > >> 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 <imbrenda@linux.vnet.ibm.com> > >>> --- > >>> 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; > >>> > >> > > >
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;
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. 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 <imbrenda@linux.vnet.ibm.com> --- virt/kvm/kvm_main.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)