diff --git a/src/bhyve/bhyve_process.c b/src/bhyve/bhyve_process.c
index 18002b559b..d46786d393 100644
--- a/src/bhyve/bhyve_process.c
+++ b/src/bhyve/bhyve_process.c
@@ -293,7 +293,7 @@ virBhyveProcessStop(struct _bhyveConn *driver,
         return 0;
     }
 
-    if (vm->pid <= 0) {
+    if (vm->pid == 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("Invalid PID %d for VM"),
                        (int)vm->pid);
@@ -329,7 +329,7 @@ virBhyveProcessStop(struct _bhyveConn *driver,
                            bhyveProcessAutoDestroy);
 
     virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, reason);
-    vm->pid = -1;
+    vm->pid = 0;
     vm->def->id = -1;
 
     bhyveProcessStopHook(vm, VIR_HOOK_BHYVE_OP_RELEASE);
@@ -344,7 +344,7 @@ virBhyveProcessStop(struct _bhyveConn *driver,
 int
 virBhyveProcessShutdown(virDomainObj *vm)
 {
-    if (vm->pid <= 0) {
+    if (vm->pid == 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("Invalid PID %d for VM"),
                        (int)vm->pid);
@@ -433,7 +433,7 @@ virBhyveProcessReconnect(virDomainObj *vm,
     if (!virDomainObjIsActive(vm))
         return 0;
 
-    if (!vm->pid)
+    if (vm->pid == 0)
         return 0;
 
     virObjectLock(vm);
diff --git a/src/ch/ch_domain.c b/src/ch/ch_domain.c
index bb489a74e3..5ab526ba1b 100644
--- a/src/ch/ch_domain.c
+++ b/src/ch/ch_domain.c
@@ -405,7 +405,7 @@ virCHDomainGetMachineName(virDomainObj *vm)
     virCHDriver *driver = priv->driver;
     char *ret = NULL;
 
-    if (vm->pid > 0) {
+    if (vm->pid != 0) {
         ret = virSystemdGetMachineNameByPID(vm->pid);
         if (!ret)
             virResetLastError();
diff --git a/src/ch/ch_process.c b/src/ch/ch_process.c
index 977082d585..4247902bcf 100644
--- a/src/ch/ch_process.c
+++ b/src/ch/ch_process.c
@@ -574,7 +574,7 @@ virCHProcessStop(virCHDriver *driver G_GNUC_UNUSED,
                  vm->def->name);
     }
 
-    vm->pid = -1;
+    vm->pid = 0;
     vm->def->id = -1;
     g_clear_pointer(&priv->machineName, g_free);
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 6906db4af5..e7e0f24443 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -3059,7 +3059,7 @@ struct _virDomainObj {
     virObjectLockable parent;
     virCond cond;
 
-    pid_t pid;
+    pid_t pid; /* 0 for no PID, avoid negative values like -1 */
     virDomainStateReason state;
 
     unsigned int autostart : 1;
diff --git a/src/hypervisor/domain_cgroup.c b/src/hypervisor/domain_cgroup.c
index 8072465615..7265325406 100644
--- a/src/hypervisor/domain_cgroup.c
+++ b/src/hypervisor/domain_cgroup.c
@@ -517,7 +517,7 @@ virDomainCgroupSetupCgroup(const char *prefix,
                            bool privileged,
                            char *machineName)
 {
-    if (!vm->pid) {
+    if (vm->pid == 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Cannot setup cgroups until process is started"));
         return -1;
diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c
index 9722d8e1de..d162812a74 100644
--- a/src/lxc/lxc_process.c
+++ b/src/lxc/lxc_process.c
@@ -217,7 +217,7 @@ static void virLXCProcessCleanup(virLXCDriver *driver,
     lxcProcessRemoveDomainStatus(cfg, vm);
 
     virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, reason);
-    vm->pid = -1;
+    vm->pid = 0;
     vm->def->id = -1;
 
     if (!!g_atomic_int_dec_and_test(&driver->nactive) && driver->inhibitCallback)
@@ -892,7 +892,7 @@ int virLXCProcessStop(virLXCDriver *driver,
                            _("Some processes refused to die"));
             return -1;
         }
-    } else if (vm->pid > 0) {
+    } else if (vm->pid != 0) {
         /* If cgroup doesn't exist, just try cleaning up the
          * libvirt_lxc process */
         if (virProcessKillPainfully(vm->pid, true) < 0) {
@@ -1033,7 +1033,7 @@ virLXCProcessReadLogOutputData(virDomainObj *vm,
         bool isdead = false;
         char *eol;
 
-        if (vm->pid <= 0 ||
+        if (vm->pid == 0 ||
             (kill(vm->pid, 0) == -1 && errno == ESRCH))
             isdead = true;
 
diff --git a/src/openvz/openvz_conf.c b/src/openvz/openvz_conf.c
index 191c79e1e2..79ab786355 100644
--- a/src/openvz/openvz_conf.c
+++ b/src/openvz/openvz_conf.c
@@ -528,7 +528,7 @@ int openvzLoadDomains(struct openvz_driver *driver)
         if (STREQ(status, "stopped")) {
             virDomainObjSetState(dom, VIR_DOMAIN_SHUTOFF,
                                  VIR_DOMAIN_SHUTOFF_UNKNOWN);
-            dom->pid = -1;
+            dom->pid = 0;
         } else {
             virDomainObjSetState(dom, VIR_DOMAIN_RUNNING,
                                  VIR_DOMAIN_RUNNING_UNKNOWN);
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 31e60c7359..8ebf152d95 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -10741,7 +10741,7 @@ qemuDomainGetMachineName(virDomainObj *vm)
     virQEMUDriver *driver = priv->driver;
     char *ret = NULL;
 
-    if (vm->pid > 0) {
+    if (vm->pid != 0) {
         ret = virSystemdGetMachineNameByPID(vm->pid);
         if (!ret)
             virResetLastError();
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index c6d965d720..1593ca7933 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -8233,7 +8233,7 @@ void qemuProcessStop(virQEMUDriver *driver,
     g_clear_pointer(&vm->deprecations, g_free);
     vm->ndeprecations = 0;
     vm->taint = 0;
-    vm->pid = -1;
+    vm->pid = 0;
     virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, reason);
     for (i = 0; i < vm->def->niothreadids; i++)
         vm->def->iothreadids[i]->thread_id = 0;
@@ -8963,7 +8963,7 @@ qemuProcessReconnectHelper(virDomainObj *obj,
     g_autofree char *name = NULL;
 
     /* If the VM was inactive, we don't need to reconnect */
-    if (!obj->pid)
+    if (obj->pid == 0)
         return 0;
 
     data = g_new0(struct qemuProcessReconnectData, 1);
diff --git a/tests/qemusecuritytest.c b/tests/qemusecuritytest.c
index 924c625a4c..4e2343b7d7 100644
--- a/tests/qemusecuritytest.c
+++ b/tests/qemusecuritytest.c
@@ -54,7 +54,6 @@ prepareObjects(virQEMUDriver *driver,
     if (!(vm = virDomainObjNew(driver->xmlopt)))
         return -1;
 
-    vm->pid = -1;
     priv = vm->privateData;
     priv->chardevStdioLogd = false;
     priv->rememberOwner = true;