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 five environment variables:
CREATED indicates how many times a new VM has been created. It is
useful for example to trigger specific actions when the first
VM is started
COUNT indicates how many VMs are currently active. This can be used for
logging or monitoring purposes
PID has the pid of the KVM process that has been started or stopped.
This can be used to perform process-specific tuning.
STATS_PATH contains the path in debugfs to the directory with all the
runtime statistics for this VM. This is useful for performance
monitoring and profiling.
EVENT described the type of event, its value can be either "create" or
"destroy"
Specific udev rules can be then set up in userspace to deal with the
creation or destruction of VMs as needed.
v3 -> v4:
* fixed subject line
* reworked kvm_uevent_notify_change to use struct kobj_uevent_env and
add_uevent_var for improved readability.
v2 -> v3:
* added EVENT
* shortened the names of the other variables
v1 -> v2:
* added KVM_VM_PID and KVM_VM_STATS_PATH
* some cleanup, the patch should look nicer now
* rebased on 4.12
Claudio Imbrenda (1):
KVM: trigger uevents when creating or destroying a VM
virt/kvm/kvm_main.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
--
2.7.4
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 five environment variables:
CREATED indicates how many times a new VM has been created. It is
useful for example to trigger specific actions when the first
VM is started
COUNT indicates how many VMs are currently active. This can be used for
logging or monitoring purposes
PID has the pid of the KVM process that has been started or stopped.
This can be used to perform process-specific tuning.
STATS_PATH contains the path in debugfs to the directory with all the
runtime statistics for this VM. This is useful for performance
monitoring and profiling.
EVENT described the type of event, its value can be either "create" or
"destroy"
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 <[email protected]>
---
virt/kvm/kvm_main.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f0fe9d0..4a7a632 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -130,6 +130,12 @@ EXPORT_SYMBOL_GPL(kvm_rebooting);
static bool largepages_enabled = true;
+#define KVM_EVENT_CREATE_VM 0
+#define KVM_EVENT_DESTROY_VM 1
+static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
+static unsigned long long kvm_createvm_count;
+static unsigned long long kvm_active_vms;
+
bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
{
if (pfn_valid(pfn))
@@ -728,6 +734,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
int i;
struct mm_struct *mm = kvm->mm;
+ kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
kvm_destroy_vm_debugfs(kvm);
kvm_arch_sync_events(kvm);
spin_lock(&kvm_lock);
@@ -3196,6 +3203,7 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
fput(file);
return -ENOMEM;
}
+ kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
fd_install(r, file);
return r;
@@ -3848,6 +3856,72 @@ static const struct file_operations *stat_fops[] = {
[KVM_STAT_VM] = &vm_stat_fops,
};
+static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
+{
+ struct kobj_uevent_env *env;
+ char *tmp, *pathbuf = NULL;
+ unsigned long long created, active;
+
+ if (!kvm_dev.this_device || !kvm)
+ return;
+
+ spin_lock(&kvm_lock);
+ if (type == KVM_EVENT_CREATE_VM) {
+ kvm_createvm_count++;
+ kvm_active_vms++;
+ } else if (type == KVM_EVENT_DESTROY_VM) {
+ kvm_active_vms--;
+ }
+ created = kvm_createvm_count;
+ active = kvm_active_vms;
+ spin_unlock(&kvm_lock);
+
+ env = kzalloc(sizeof(*env), GFP_KERNEL);
+ if (!env)
+ return;
+
+ add_uevent_var(env, "CREATED=%llu", created);
+ add_uevent_var(env, "COUNT=%llu", active);
+
+ if (kvm->mm && kvm->mm->owner) {
+ add_uevent_var(env, "PID=%d", kvm->mm->owner->pid);
+ } else if (kvm->debugfs_dentry) {
+ char p[ITOA_MAX_LEN];
+
+ snprintf(p, sizeof(p), "%s", kvm->debugfs_dentry->d_name.name);
+ tmp = strchrnul(p + 1, '-');
+ *tmp = '\0';
+ add_uevent_var(env, "PID=%s", p);
+ }
+
+ if (type == KVM_EVENT_CREATE_VM)
+ add_uevent_var(env, "EVENT=create");
+ else if (type == KVM_EVENT_DESTROY_VM)
+ add_uevent_var(env, "EVENT=destroy");
+
+ if (kvm->debugfs_dentry) {
+ pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (pathbuf) {
+ /* sizeof counts the final '\0' */
+ int len = sizeof("STATS_PATH=") - 1;
+ const char *pvar = "STATS_PATH=";
+
+ tmp = dentry_path_raw(kvm->debugfs_dentry,
+ pathbuf + len,
+ PATH_MAX - len);
+ if (!IS_ERR(tmp)) {
+ memcpy(tmp - len, pvar, len);
+ env->envp[env->envp_idx++] = tmp - len;
+ }
+ }
+ }
+ /* no need for checks, since we are adding at most only 5 keys */
+ env->envp[env->envp_idx++] = NULL;
+ kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
+ kfree(env);
+ kfree(pathbuf);
+}
+
static int kvm_init_debug(void)
{
int r = -EEXIST;
--
2.7.4
Hi Claudio,
[auto build test ERROR on kvm/linux-next]
[also build test ERROR on v4.12 next-20170711]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Claudio-Imbrenda/KVM-trigger-uevents-when-creating-or-destroying-a-VM/20170712-023748
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
config: x86_64-allyesdebian (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
arch/x86/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_uevent_notify_change':
>> arch/x86/kvm/../../../virt/kvm/kvm_main.c:3892:24: error: 'struct mm_struct' has no member named 'owner'
if (kvm->mm && kvm->mm->owner) {
^~
arch/x86/kvm/../../../virt/kvm/kvm_main.c:3893:40: error: 'struct mm_struct' has no member named 'owner'
add_uevent_var(env, "PID=%d", kvm->mm->owner->pid);
^~
vim +3892 arch/x86/kvm/../../../virt/kvm/kvm_main.c
3864
3865 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
3866 {
3867 struct kobj_uevent_env *env;
3868 char *tmp, *pathbuf = NULL;
3869 unsigned long long created, active;
3870
3871 if (!kvm_dev.this_device || !kvm)
3872 return;
3873
3874 spin_lock(&kvm_lock);
3875 if (type == KVM_EVENT_CREATE_VM) {
3876 kvm_createvm_count++;
3877 kvm_active_vms++;
3878 } else if (type == KVM_EVENT_DESTROY_VM) {
3879 kvm_active_vms--;
3880 }
3881 created = kvm_createvm_count;
3882 active = kvm_active_vms;
3883 spin_unlock(&kvm_lock);
3884
3885 env = kzalloc(sizeof(*env), GFP_KERNEL);
3886 if (!env)
3887 return;
3888
3889 add_uevent_var(env, "CREATED=%llu", created);
3890 add_uevent_var(env, "COUNT=%llu", active);
3891
> 3892 if (kvm->mm && kvm->mm->owner) {
3893 add_uevent_var(env, "PID=%d", kvm->mm->owner->pid);
3894 } else if (kvm->debugfs_dentry) {
3895 char p[ITOA_MAX_LEN];
3896
3897 snprintf(p, sizeof(p), "%s", kvm->debugfs_dentry->d_name.name);
3898 tmp = strchrnul(p + 1, '-');
3899 *tmp = '\0';
3900 add_uevent_var(env, "PID=%s", p);
3901 }
3902
3903 if (type == KVM_EVENT_CREATE_VM)
3904 add_uevent_var(env, "EVENT=create");
3905 else if (type == KVM_EVENT_DESTROY_VM)
3906 add_uevent_var(env, "EVENT=destroy");
3907
3908 if (kvm->debugfs_dentry) {
3909 pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
3910 if (pathbuf) {
3911 /* sizeof counts the final '\0' */
3912 int len = sizeof("STATS_PATH=") - 1;
3913 const char *pvar = "STATS_PATH=";
3914
3915 tmp = dentry_path_raw(kvm->debugfs_dentry,
3916 pathbuf + len,
3917 PATH_MAX - len);
3918 if (!IS_ERR(tmp)) {
3919 memcpy(tmp - len, pvar, len);
3920 env->envp[env->envp_idx++] = tmp - len;
3921 }
3922 }
3923 }
3924 /* no need for checks, since we are adding at most only 5 keys */
3925 env->envp[env->envp_idx++] = NULL;
3926 kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
3927 kfree(env);
3928 kfree(pathbuf);
3929 }
3930
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Claudio,
[auto build test ERROR on kvm/linux-next]
[also build test ERROR on v4.12 next-20170711]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Claudio-Imbrenda/KVM-trigger-uevents-when-creating-or-destroying-a-VM/20170712-023748
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
config: powerpc-defconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 6.3.0-18) 6.3.0 20170516
reproduce:
wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=powerpc
All errors (new ones prefixed by >>):
arch/powerpc/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_uevent_notify_change':
>> arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:3892:24: error: 'struct mm_struct' has no member named 'owner'
if (kvm->mm && kvm->mm->owner) {
^~
arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:3893:40: error: 'struct mm_struct' has no member named 'owner'
add_uevent_var(env, "PID=%d", kvm->mm->owner->pid);
^~
vim +3892 arch/powerpc/kvm/../../../virt/kvm/kvm_main.c
3864
3865 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
3866 {
3867 struct kobj_uevent_env *env;
3868 char *tmp, *pathbuf = NULL;
3869 unsigned long long created, active;
3870
3871 if (!kvm_dev.this_device || !kvm)
3872 return;
3873
3874 spin_lock(&kvm_lock);
3875 if (type == KVM_EVENT_CREATE_VM) {
3876 kvm_createvm_count++;
3877 kvm_active_vms++;
3878 } else if (type == KVM_EVENT_DESTROY_VM) {
3879 kvm_active_vms--;
3880 }
3881 created = kvm_createvm_count;
3882 active = kvm_active_vms;
3883 spin_unlock(&kvm_lock);
3884
3885 env = kzalloc(sizeof(*env), GFP_KERNEL);
3886 if (!env)
3887 return;
3888
3889 add_uevent_var(env, "CREATED=%llu", created);
3890 add_uevent_var(env, "COUNT=%llu", active);
3891
> 3892 if (kvm->mm && kvm->mm->owner) {
3893 add_uevent_var(env, "PID=%d", kvm->mm->owner->pid);
3894 } else if (kvm->debugfs_dentry) {
3895 char p[ITOA_MAX_LEN];
3896
3897 snprintf(p, sizeof(p), "%s", kvm->debugfs_dentry->d_name.name);
3898 tmp = strchrnul(p + 1, '-');
3899 *tmp = '\0';
3900 add_uevent_var(env, "PID=%s", p);
3901 }
3902
3903 if (type == KVM_EVENT_CREATE_VM)
3904 add_uevent_var(env, "EVENT=create");
3905 else if (type == KVM_EVENT_DESTROY_VM)
3906 add_uevent_var(env, "EVENT=destroy");
3907
3908 if (kvm->debugfs_dentry) {
3909 pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
3910 if (pathbuf) {
3911 /* sizeof counts the final '\0' */
3912 int len = sizeof("STATS_PATH=") - 1;
3913 const char *pvar = "STATS_PATH=";
3914
3915 tmp = dentry_path_raw(kvm->debugfs_dentry,
3916 pathbuf + len,
3917 PATH_MAX - len);
3918 if (!IS_ERR(tmp)) {
3919 memcpy(tmp - len, pvar, len);
3920 env->envp[env->envp_idx++] = tmp - len;
3921 }
3922 }
3923 }
3924 /* no need for checks, since we are adding at most only 5 keys */
3925 env->envp[env->envp_idx++] = NULL;
3926 kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
3927 kfree(env);
3928 kfree(pathbuf);
3929 }
3930
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation