From fdeaf7e3eb37c6dbc4b4ac97dbe1945d239eb788 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 24 Jul 2017 13:40:03 +0200 Subject: [PATCH] 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: Janosch Frank Fixes: 286de8f6ac9202 ("KVM: trigger uevents when creating or destroying a VM") Signed-off-by: Claudio Imbrenda Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 35 ++++++++++++----------------------- 2 files changed, 13 insertions(+), 23 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 648b34cabb38..890b706d1943 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -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, ...) \ diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 82987d457b8b..f3f74271f1a9 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -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]; - - 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; - } + char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL); + + 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) -- 2.20.1