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Commit fdeaf7e3 authored by Claudio Imbrenda's avatar Claudio Imbrenda Committed by Paolo Bonzini
Browse files

KVM: make pid available for uevents without debugfs 



Simplify and improve the code so that the PID is always available in
the uevent even when debugfs is not available.

This adds a userspace_pid field to struct kvm, as per Radim's
suggestion, so that the PID can be retrieved on destruction too.

Acked-by: default avatarJanosch Frank <frankja@linux.vnet.ibm.com>
Fixes: 286de8f6 ("KVM: trigger uevents when creating or destroying a VM")
Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent fa19871a

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -445,6 +445,7 @@ struct kvm { 
	struct kvm_stat_data **debugfs_stat_data;

	struct srcu_struct srcu;

	struct srcu_struct irq_srcu;

	pid_t userspace_pid;

};



#define kvm_err(fmt, ...) \

virt/kvm/kvm_main.c

+12 −23
Original line number Diff line number Diff line
@@ -3883,7 +3883,6 @@ static const struct file_operations *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)
@@ -3907,38 +3906,28 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) 
	add_uevent_var(env, "CREATED=%llu", created);

	add_uevent_var(env, "COUNT=%llu", active);



	if (type == KVM_EVENT_CREATE_VM)

	if (type == KVM_EVENT_CREATE_VM) {

		add_uevent_var(env, "EVENT=create");

	else if (type == KVM_EVENT_DESTROY_VM)

		kvm->userspace_pid = task_pid_nr(current);

	} else if (type == KVM_EVENT_DESTROY_VM) {

		add_uevent_var(env, "EVENT=destroy");

	}

	add_uevent_var(env, "PID=%d", kvm->userspace_pid);



	if (kvm->debugfs_dentry) {

		char p[ITOA_MAX_LEN];

		char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);



		snprintf(p, sizeof(p), "%s", kvm->debugfs_dentry->d_name.name);

		tmp = strchrnul(p + 1, '-');

		*tmp = '\0';

		add_uevent_var(env, "PID=%s", p);

		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;

			}

		if (p) {

			tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);

			if (!IS_ERR(tmp))

				add_uevent_var(env, "STATS_PATH=%s", tmp);

			kfree(p);

		}

	}

	/* 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)