diff --git a/src/hypervisor/domain_driver.c b/src/hypervisor/domain_driver.c
index a70f75f3ae..d9469ad6f9 100644
--- a/src/hypervisor/domain_driver.c
+++ b/src/hypervisor/domain_driver.c
@@ -462,6 +462,7 @@ virDomainDriverNodeDeviceReAttach(virNodeDevicePtr dev,
 int
 virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
                                      virHostdevManager *hostdevMgr,
+                                     virPCIStubDriver driverType,
                                      const char *driverName)
 {
     g_autoptr(virPCIDevice) pci = NULL;
@@ -471,8 +472,10 @@ virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
     g_autoptr(virConnect) nodeconn = NULL;
     g_autoptr(virNodeDevice) nodedev = NULL;
 
-    if (!driverName)
+    if (driverType == VIR_PCI_STUB_DRIVER_NONE) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("driver type not set"));
         return -1;
+    }
 
     if (!(nodeconn = virGetConnectNodeDev()))
         return -1;
@@ -504,10 +507,8 @@ virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
     if (!pci)
         return -1;
 
-    if (STREQ(driverName, "vfio"))
-        virPCIDeviceSetStubDriverType(pci, VIR_PCI_STUB_DRIVER_VFIO);
-    else if (STREQ(driverName, "xen"))
-        virPCIDeviceSetStubDriverType(pci, VIR_PCI_STUB_DRIVER_XEN);
+    virPCIDeviceSetStubDriverType(pci, driverType);
+    virPCIDeviceSetStubDriverName(pci, driverName);
 
     return virHostdevPCINodeDeviceDetach(hostdevMgr, pci);
 }
diff --git a/src/hypervisor/domain_driver.h b/src/hypervisor/domain_driver.h
index 4241c86932..9942f58fda 100644
--- a/src/hypervisor/domain_driver.h
+++ b/src/hypervisor/domain_driver.h
@@ -22,6 +22,7 @@
 
 #include "node_device_conf.h"
 #include "virhostdev.h"
+#include "virpci.h"
 
 char *
 virDomainDriverGenerateRootHash(const char *drivername,
@@ -58,6 +59,7 @@ int virDomainDriverNodeDeviceReAttach(virNodeDevicePtr dev,
 
 int virDomainDriverNodeDeviceDetachFlags(virNodeDevicePtr dev,
                                          virHostdevManager *hostdevMgr,
+                                         virPCIStubDriver driverType,
                                          const char *driverName);
 
 int virDomainDriverAddIOThreadCheck(virDomainDef *def,
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 3d10f45850..079922dd32 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -5876,7 +5876,8 @@ libxlNodeDeviceDetachFlags(virNodeDevicePtr dev,
 
     /* virNodeDeviceDetachFlagsEnsureACL() is being called by
      * virDomainDriverNodeDeviceDetachFlags() */
-    return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr, driverName);
+    return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr,
+                                                VIR_PCI_STUB_DRIVER_XEN, NULL);
 }
 
 static int
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 73fa499e40..5128b64364 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -70,7 +70,6 @@
 #include "domain_driver.h"
 #include "domain_postparse.h"
 #include "domain_validate.h"
-#include "virpci.h"
 #include "virpidfile.h"
 #include "virprocess.h"
 #include "libvirt_internal.h"
@@ -11407,24 +11406,28 @@ qemuNodeDeviceDetachFlags(virNodeDevicePtr dev,
 
     virCheckFlags(0, -1);
 
-    if (!driverName)
-        driverName = "vfio";
+    /* For historical reasons, if driverName is "vfio", that is the
+     * same as NULL, i.e. the default vfio driver for this device
+     */
+    if (STREQ_NULLABLE(driverName, "vfio"))
+        driverName = NULL;
 
-    /* Only the 'vfio' driver is supported and a special error message for
-     * the previously supported 'kvm' driver is provided below. */
-    if (STRNEQ(driverName, "vfio") && STRNEQ(driverName, "kvm")) {
-        virReportError(VIR_ERR_INVALID_ARG,
-                       _("unknown driver name '%1$s'"), driverName);
-        return -1;
-    }
-
-    if (STREQ(driverName, "kvm")) {
+    /* the "kvm" driver name was used a very long time ago to force
+     * "legacy KVM device assignment", which hasn't been supported in
+     * over 10 years.
+     */
+    if (STREQ_NULLABLE(driverName, "kvm")) {
         virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
-                       _("KVM device assignment is no longer "
+                       _("'legacy KVM' device assignment is no longer "
                          "supported on this system"));
         return -1;
     }
 
+    /* for any other driver, we can't know whether or not it is a VFIO
+     * driver until the device has been bound to it, so we will defer
+     * further validation until then.
+     */
+
     if (!qemuHostdevHostSupportsPassthroughVFIO()) {
         virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
                        _("VFIO device assignment is currently not "
@@ -11434,7 +11437,9 @@ qemuNodeDeviceDetachFlags(virNodeDevicePtr dev,
 
     /* virNodeDeviceDetachFlagsEnsureACL() is being called by
      * virDomainDriverNodeDeviceDetachFlags() */
-    return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr, driverName);
+    return virDomainDriverNodeDeviceDetachFlags(dev, hostdev_mgr,
+                                                VIR_PCI_STUB_DRIVER_VFIO,
+                                                driverName);
 }
 
 static int