diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 8f0245a504..12a0462ce7 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -301,23 +301,6 @@ qemuBuildMasterKeyCommandLine(virCommand *cmd,
 }
 
 
-/**
- * qemuBuildFDSet:
- * @fd: fd to reassign to the child
- * @idx: index in the fd set
- *
- * Format the parameters for the -add-fd command line option
- * for the given file descriptor. The file descriptor must previously
- * have been 'transferred' in a virCommandPassFDIndex() call,
- * and @idx is the value returned by that call.
- */
-static char *
-qemuBuildFDSet(int fd, size_t idx)
-{
-    return g_strdup_printf("set=%zu,fd=%d", idx, fd);
-}
-
-
 /**
  * qemuVirCommandGetFDSet:
  * @cmd: the command to modify
@@ -1362,8 +1345,8 @@ qemuBuildChardevStr(const virDomainChrSourceDef *dev,
         path = dev->data.file.path;
         append = dev->data.file.append;
 
-        if (chrSourcePriv->fdset) {
-            path = chrSourcePriv->fdset;
+        if (chrSourcePriv->sourcefd) {
+            path = qemuFDPassGetPath(chrSourcePriv->sourcefd);
             append = VIR_TRISTATE_SWITCH_ON;
         }
 
@@ -1430,8 +1413,8 @@ qemuBuildChardevStr(const virDomainChrSourceDef *dev,
 
     case VIR_DOMAIN_CHR_TYPE_UNIX:
         virBufferAsprintf(&buf, "socket,id=%s", charAlias);
-        if (chrSourcePriv->passedFD != -1) {
-            virBufferAsprintf(&buf, ",fd=%d", chrSourcePriv->passedFD);
+        if (chrSourcePriv->sourcefd) {
+            virBufferAsprintf(&buf, ",fd=%s", qemuFDPassGetPath(chrSourcePriv->sourcefd));
         } else {
             virBufferAddLit(&buf, ",path=");
             virQEMUBuildBufferEscapeComma(&buf, dev->data.nix.path);
@@ -1466,8 +1449,8 @@ qemuBuildChardevStr(const virDomainChrSourceDef *dev,
         path = dev->logfile;
         append = dev->logappend;
 
-        if (chrSourcePriv->logFdset) {
-            path = chrSourcePriv->logFdset;
+        if (chrSourcePriv->logfd) {
+            path = qemuFDPassGetPath(chrSourcePriv->logfd);
             append = VIR_TRISTATE_SWITCH_ON;
         }
 
@@ -1527,28 +1510,8 @@ qemuBuildChardevCommand(virCommand *cmd,
         break;
 
     case VIR_DOMAIN_CHR_TYPE_FILE:
-        if (chrSourcePriv->fd != -1) {
-            g_autofree char *fdset = NULL;
-            size_t idx;
-
-            virCommandPassFDIndex(cmd, chrSourcePriv->fd,
-                                  VIR_COMMAND_PASS_FD_CLOSE_PARENT, &idx);
-            fdset = qemuBuildFDSet(chrSourcePriv->fd, idx);
-            chrSourcePriv->fd = -1;
-
-            virCommandAddArg(cmd, "-add-fd");
-            virCommandAddArg(cmd, fdset);
-
-            chrSourcePriv->fdset = g_strdup_printf("/dev/fdset/%zu", idx);
-        }
-        break;
-
     case VIR_DOMAIN_CHR_TYPE_UNIX:
-        if (chrSourcePriv->fd != -1) {
-            virCommandPassFD(cmd, chrSourcePriv->fd, VIR_COMMAND_PASS_FD_CLOSE_PARENT);
-            chrSourcePriv->passedFD = chrSourcePriv->fd;
-            chrSourcePriv->fd = -1;
-        }
+        qemuFDPassTransferCommand(chrSourcePriv->sourcefd, cmd);
         break;
 
     case VIR_DOMAIN_CHR_TYPE_NULL:
@@ -1571,20 +1534,7 @@ qemuBuildChardevCommand(virCommand *cmd,
         return -1;
     }
 
-    if (chrSourcePriv->logfd != -1) {
-        g_autofree char *fdset = NULL;
-        size_t idx;
-
-        virCommandPassFDIndex(cmd, chrSourcePriv->logfd,
-                              VIR_COMMAND_PASS_FD_CLOSE_PARENT, &idx);
-        fdset = qemuBuildFDSet(chrSourcePriv->logfd, idx);
-        chrSourcePriv->logfd = -1;
-
-        virCommandAddArg(cmd, "-add-fd");
-        virCommandAddArg(cmd, fdset);
-
-        chrSourcePriv->logFdset = g_strdup_printf("/dev/fdset/%zu", idx);
-    }
+    qemuFDPassTransferCommand(chrSourcePriv->logfd, cmd);
 
     if (!(charstr = qemuBuildChardevStr(dev, charAlias)))
         return -1;
@@ -5001,8 +4951,12 @@ qemuBuildVideoCommandLine(virCommand *cmd,
             qemuDomainChrSourcePrivate *chrsrcpriv = QEMU_DOMAIN_CHR_SOURCE_PRIVATE(chrsrc);
 
             chrsrc->type = VIR_DOMAIN_CHR_TYPE_UNIX;
-            chrsrcpriv->fd = videopriv->vhost_user_fd;
-            videopriv->vhost_user_fd = -1;
+            chrsrcpriv->sourcefd = qemuFDPassNewDirect(video->info.alias, priv);
+
+            if (qemuFDPassAddFD(chrsrcpriv->sourcefd,
+                                &videopriv->vhost_user_fd,
+                                "-vhost-user") < 0)
+                return -1;
 
             if (qemuBuildChardevCommand(cmd, chrsrc, chrAlias, priv->qemuCaps) < 0)
                 return -1;
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index c096e5bb9a..469942d201 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -904,11 +904,6 @@ qemuDomainChrSourcePrivateNew(void)
     if (!(priv = virObjectNew(qemuDomainChrSourcePrivateClass)))
         return NULL;
 
-    priv->fd = -1;
-    priv->logfd = -1;
-
-    priv->passedFD = -1;
-
     return (virObject *) priv;
 }
 
@@ -918,13 +913,11 @@ qemuDomainChrSourcePrivateDispose(void *obj)
 {
     qemuDomainChrSourcePrivate *priv = obj;
 
-    VIR_FORCE_CLOSE(priv->fd);
-    VIR_FORCE_CLOSE(priv->logfd);
+    qemuFDPassFree(priv->sourcefd);
+    qemuFDPassFree(priv->logfd);
 
     g_free(priv->tlsCertPath);
 
-    g_free(priv->fdset);
-    g_free(priv->logFdset);
     g_free(priv->tlsCredsAlias);
 
     g_clear_pointer(&priv->secinfo, qemuDomainSecretInfoFree);
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 52b500f294..c60aa44d6f 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -36,6 +36,7 @@
 #include "qemu_capabilities.h"
 #include "qemu_migration_params.h"
 #include "qemu_slirp.h"
+#include "qemu_fd.h"
 #include "virmdev.h"
 #include "virchrdev.h"
 #include "virobject.h"
@@ -347,16 +348,13 @@ struct _qemuDomainChrSourcePrivate {
      * NB: *not* to be written to qemu domain object XML */
     qemuDomainSecretInfo *secinfo;
 
-    int fd; /* file descriptor of the chardev source */
-    int logfd; /* file descriptor of the logging source */
+    qemuFDPass *sourcefd;
+    qemuFDPass *logfd;
     bool wait; /* wait for incoming connections on chardev */
 
     char *tlsCertPath; /* path to certificates if TLS is requested */
     bool tlsVerify; /* whether server should verify client certificates */
 
-    char *fdset; /* fdset path corresponding to the passed filedescriptor */
-    char *logFdset; /* fdset path corresponding to the passed filedescriptor for logfile */
-    int passedFD; /* filedescriptor number when fdset passing it directly */
     char *tlsCredsAlias; /* alias of the x509 tls credentials object */
 };
 
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index d8008e1c89..01116312c4 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -6781,6 +6781,7 @@ struct qemuProcessPrepareHostBackendChardevData {
     virLogManager *logManager;
     virQEMUDriverConfig *cfg;
     virDomainDef *def;
+    const char *fdprefix;
 };
 
 
@@ -6791,10 +6792,14 @@ qemuProcessPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
 {
     struct qemuProcessPrepareHostBackendChardevData *data = opaque;
     qemuDomainChrSourcePrivate *charpriv = QEMU_DOMAIN_CHR_SOURCE_PRIVATE(chardev);
+    const char *devalias = NULL;
 
     /* this function is also called for the monitor backend which doesn't have
      * a 'dev' */
     if (dev) {
+        virDomainDeviceInfo *info = virDomainDeviceGetInfo(dev);
+        devalias = info->alias;
+
         /* vhost-user disk doesn't use FD passing */
         if (dev->type == VIR_DOMAIN_DEVICE_DISK)
             return 0;
@@ -6808,6 +6813,8 @@ qemuProcessPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
         /* TPMs FD passing setup is special and handled separately */
         if (dev->type == VIR_DOMAIN_DEVICE_TPM)
             return 0;
+    } else {
+        devalias = data->fdprefix;
     }
 
     switch ((virDomainChrType) chardev->type) {
@@ -6823,33 +6830,42 @@ qemuProcessPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
     case VIR_DOMAIN_CHR_TYPE_SPICEPORT:
         break;
 
-    case VIR_DOMAIN_CHR_TYPE_FILE:
+    case VIR_DOMAIN_CHR_TYPE_FILE: {
+        VIR_AUTOCLOSE sourcefd = -1;
+
         if (qemuProcessPrepareHostBackendChardevFileHelper(chardev->data.file.path,
                                                            chardev->data.file.append,
-                                                           &charpriv->fd,
+                                                           &sourcefd,
                                                            data->logManager,
                                                            data->priv->driver->securityManager,
                                                            data->cfg,
                                                            data->def) < 0)
             return -1;
 
+        charpriv->sourcefd = qemuFDPassNew(devalias, data->priv);
+
+        if (qemuFDPassAddFD(charpriv->sourcefd, &sourcefd, "-source") < 0)
+            return -1;
+    }
         break;
 
     case VIR_DOMAIN_CHR_TYPE_UNIX:
         if (chardev->data.nix.listen &&
             virQEMUCapsGet(data->priv->qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS_COMMANDLINE)) {
+            VIR_AUTOCLOSE sourcefd = -1;
 
             if (qemuSecuritySetSocketLabel(data->priv->driver->securityManager, data->def) < 0)
                 return -1;
 
-            charpriv->fd = qemuOpenChrChardevUNIXSocket(chardev);
+            sourcefd = qemuOpenChrChardevUNIXSocket(chardev);
 
-            if (qemuSecurityClearSocketLabel(data->priv->driver->securityManager, data->def) < 0) {
-                VIR_FORCE_CLOSE(charpriv->fd);
+            if (qemuSecurityClearSocketLabel(data->priv->driver->securityManager, data->def) < 0 ||
+                sourcefd < 0)
                 return -1;
-            }
 
-            if (charpriv->fd < 0)
+            charpriv->sourcefd = qemuFDPassNewDirect(devalias, data->priv);
+
+            if (qemuFDPassAddFD(charpriv->sourcefd, &sourcefd, "-source") < 0)
                 return -1;
         }
         break;
@@ -6864,14 +6880,21 @@ qemuProcessPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
     }
 
     if (chardev->logfile) {
+        VIR_AUTOCLOSE logfd = -1;
+
         if (qemuProcessPrepareHostBackendChardevFileHelper(chardev->logfile,
                                                            chardev->logappend,
-                                                           &charpriv->logfd,
+                                                           &logfd,
                                                            data->logManager,
                                                            data->priv->driver->securityManager,
                                                            data->cfg,
                                                            data->def) < 0)
             return -1;
+
+        charpriv->logfd = qemuFDPassNew(devalias, data->priv);
+
+        if (qemuFDPassAddFD(charpriv->logfd, &logfd, "-log") < 0)
+            return -1;
     }
 
     return 0;
@@ -6904,6 +6927,8 @@ qemuProcessPrepareHostBackendChardev(virDomainObj *vm)
                                               &data) < 0)
         return -1;
 
+    data.fdprefix = "monitor";
+
     if (qemuProcessPrepareHostBackendChardevOne(NULL, priv->monConfig, &data) < 0)
         return -1;
 
diff --git a/tests/qemuxml2argvdata/aarch64-pci-serial.args b/tests/qemuxml2argvdata/aarch64-pci-serial.args
index aca88e8e60..ff27b7ac73 100644
--- a/tests/qemuxml2argvdata/aarch64-pci-serial.args
+++ b/tests/qemuxml2argvdata/aarch64-pci-serial.args
@@ -29,7 +29,7 @@ QEMU_AUDIO_DRV=none \
 -device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1 \
 -device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x0 \
 -device pcie-root-port,port=16,chassis=3,id=pci.3,bus=pcie.0,addr=0x2 \
--add-fd set=0,fd=1751 \
+-add-fd set=0,fd=1751,opaque=serial0-log \
 -chardev pty,id=charserial0,logfile=/dev/fdset/0,logappend=on \
 -device pci-serial,chardev=charserial0,id=serial0,bus=pci.2,addr=0x1 \
 -msg timestamp=on
diff --git a/tests/qemuxml2argvdata/name-escape.x86_64-2.11.0.args b/tests/qemuxml2argvdata/name-escape.x86_64-2.11.0.args
index 6d4c5bff6e..e64051e219 100644
--- a/tests/qemuxml2argvdata/name-escape.x86_64-2.11.0.args
+++ b/tests/qemuxml2argvdata/name-escape.x86_64-2.11.0.args
@@ -33,7 +33,7 @@ QEMU_AUDIO_DRV=spice \
 -device ccid-card-emulated,backend=certificates,cert1=cert1,,foo,cert2=cert2,cert3=cert3,db=/etc/pki/nssdb,,foo,id=smartcard0,bus=ccid0.0 \
 -chardev tty,id=charserial0,path=/dev/ttyS2,,foo \
 -device isa-serial,chardev=charserial0,id=serial0,index=1 \
--add-fd set=0,fd=1750 \
+-add-fd set=0,fd=1750,opaque=serial1-source \
 -chardev file,id=charserial1,path=/dev/fdset/0,append=on \
 -device isa-serial,chardev=charserial1,id=serial1,index=0 \
 -chardev pipe,id=charchannel0,path=/tmp/guestfwd,,foo \
diff --git a/tests/qemuxml2argvdata/name-escape.x86_64-latest.args b/tests/qemuxml2argvdata/name-escape.x86_64-latest.args
index 0b3247b6bd..b8ac17eee6 100644
--- a/tests/qemuxml2argvdata/name-escape.x86_64-latest.args
+++ b/tests/qemuxml2argvdata/name-escape.x86_64-latest.args
@@ -35,7 +35,7 @@ XDG_CONFIG_HOME=/tmp/lib/domain--1-foo=1,bar=2/.config \
 -device '{"driver":"ccid-card-emulated","backend":"certificates","cert1":"cert1,foo","cert2":"cert2","cert3":"cert3","db":"/etc/pki/nssdb,foo","id":"smartcard0","bus":"ccid0.0"}' \
 -chardev tty,id=charserial0,path=/dev/ttyS2,,foo \
 -device '{"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":1}' \
--add-fd set=0,fd=1750 \
+-add-fd set=0,fd=1750,opaque=serial1-source \
 -chardev file,id=charserial1,path=/dev/fdset/0,append=on \
 -device '{"driver":"isa-serial","chardev":"charserial1","id":"serial1","index":0}' \
 -chardev pipe,id=charchannel0,path=/tmp/guestfwd,,foo \
diff --git a/tests/qemuxml2argvdata/serial-file-chardev.args b/tests/qemuxml2argvdata/serial-file-chardev.args
index 7df5c2a115..a6107172de 100644
--- a/tests/qemuxml2argvdata/serial-file-chardev.args
+++ b/tests/qemuxml2argvdata/serial-file-chardev.args
@@ -29,7 +29,7 @@ QEMU_AUDIO_DRV=none \
 -usb \
 -drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
--add-fd set=0,fd=1750 \
+-add-fd set=0,fd=1750,opaque=serial0-source \
 -chardev file,id=charserial0,path=/dev/fdset/0,append=on \
 -device isa-serial,chardev=charserial0,id=serial0,index=0 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2 \
diff --git a/tests/qemuxml2argvdata/serial-file-chardev.x86_64-latest.args b/tests/qemuxml2argvdata/serial-file-chardev.x86_64-latest.args
index 6a28170503..f79a4fc775 100644
--- a/tests/qemuxml2argvdata/serial-file-chardev.x86_64-latest.args
+++ b/tests/qemuxml2argvdata/serial-file-chardev.x86_64-latest.args
@@ -31,7 +31,7 @@ XDG_CONFIG_HOME=/tmp/lib/domain--1-QEMUGuest1/.config \
 -blockdev '{"driver":"host_device","filename":"/dev/HostVG/QEMUGuest1","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
 -blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"raw","file":"libvirt-1-storage"}' \
 -device '{"driver":"ide-hd","bus":"ide.0","unit":0,"drive":"libvirt-1-format","id":"ide0-0-0","bootindex":1}' \
--add-fd set=0,fd=1750 \
+-add-fd set=0,fd=1750,opaque=serial0-source \
 -chardev file,id=charserial0,path=/dev/fdset/0,append=on \
 -device '{"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0}' \
 -audiodev '{"id":"audio1","driver":"none"}' \
diff --git a/tests/qemuxml2argvdata/serial-file-log.args b/tests/qemuxml2argvdata/serial-file-log.args
index 72d7c49298..5e23e7d888 100644
--- a/tests/qemuxml2argvdata/serial-file-log.args
+++ b/tests/qemuxml2argvdata/serial-file-log.args
@@ -29,8 +29,8 @@ QEMU_AUDIO_DRV=none \
 -usb \
 -drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
--add-fd set=0,fd=1750 \
--add-fd set=1,fd=1751 \
+-add-fd set=0,fd=1750,opaque=serial0-source \
+-add-fd set=1,fd=1751,opaque=serial0-log \
 -chardev file,id=charserial0,path=/dev/fdset/0,append=on,logfile=/dev/fdset/1,logappend=on \
 -device isa-serial,chardev=charserial0,id=serial0,index=0 \
 -msg timestamp=on
diff --git a/tests/qemuxml2argvdata/serial-file-log.x86_64-latest.args b/tests/qemuxml2argvdata/serial-file-log.x86_64-latest.args
index c12b4b3a60..a384d77187 100644
--- a/tests/qemuxml2argvdata/serial-file-log.x86_64-latest.args
+++ b/tests/qemuxml2argvdata/serial-file-log.x86_64-latest.args
@@ -31,8 +31,8 @@ XDG_CONFIG_HOME=/tmp/lib/domain--1-QEMUGuest1/.config \
 -blockdev '{"driver":"host_device","filename":"/dev/HostVG/QEMUGuest1","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
 -blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"raw","file":"libvirt-1-storage"}' \
 -device '{"driver":"ide-hd","bus":"ide.0","unit":0,"drive":"libvirt-1-format","id":"ide0-0-0","bootindex":1}' \
--add-fd set=0,fd=1750 \
--add-fd set=1,fd=1751 \
+-add-fd set=0,fd=1750,opaque=serial0-source \
+-add-fd set=1,fd=1751,opaque=serial0-log \
 -chardev file,id=charserial0,path=/dev/fdset/0,append=on,logfile=/dev/fdset/1,logappend=on \
 -device '{"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0}' \
 -audiodev '{"id":"audio1","driver":"none"}' \
diff --git a/tests/qemuxml2argvdata/serial-many-chardev.args b/tests/qemuxml2argvdata/serial-many-chardev.args
index 5e80348d11..7cd936c5a7 100644
--- a/tests/qemuxml2argvdata/serial-many-chardev.args
+++ b/tests/qemuxml2argvdata/serial-many-chardev.args
@@ -31,7 +31,7 @@ QEMU_AUDIO_DRV=none \
 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
 -chardev pty,id=charserial0 \
 -device isa-serial,chardev=charserial0,id=serial0,index=0 \
--add-fd set=0,fd=1750 \
+-add-fd set=0,fd=1750,opaque=serial1-source \
 -chardev file,id=charserial1,path=/dev/fdset/0,append=on \
 -device isa-serial,chardev=charserial1,id=serial1,index=1 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2 \
diff --git a/tests/qemuxml2argvdata/serial-many-chardev.x86_64-latest.args b/tests/qemuxml2argvdata/serial-many-chardev.x86_64-latest.args
index cbdcc82052..e34af4b121 100644
--- a/tests/qemuxml2argvdata/serial-many-chardev.x86_64-latest.args
+++ b/tests/qemuxml2argvdata/serial-many-chardev.x86_64-latest.args
@@ -33,7 +33,7 @@ XDG_CONFIG_HOME=/tmp/lib/domain--1-QEMUGuest1/.config \
 -device '{"driver":"ide-hd","bus":"ide.0","unit":0,"drive":"libvirt-1-format","id":"ide0-0-0","bootindex":1}' \
 -chardev pty,id=charserial0 \
 -device '{"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0}' \
--add-fd set=0,fd=1750 \
+-add-fd set=0,fd=1750,opaque=serial1-source \
 -chardev file,id=charserial1,path=/dev/fdset/0,append=on \
 -device '{"driver":"isa-serial","chardev":"charserial1","id":"serial1","index":1}' \
 -audiodev '{"id":"audio1","driver":"none"}' \
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index b2d6606d6e..829a238c3b 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -383,10 +383,17 @@ testPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
                                  virDomainChrSourceDef *chardev,
                                  void *opaque)
 {
-    virQEMUCaps *qemuCaps = opaque;
+    virDomainObj *vm = opaque;
+    qemuDomainObjPrivate *priv = vm->privateData;
     qemuDomainChrSourcePrivate *charpriv = QEMU_DOMAIN_CHR_SOURCE_PRIVATE(chardev);
+    int fakesourcefd = -1;
+    const char *devalias = NULL;
+    bool usefdset = true;
 
     if (dev) {
+        virDomainDeviceInfo *info = virDomainDeviceGetInfo(dev);
+        devalias = info->alias;
+
         /* vhost-user disk doesn't use FD passing */
         if (dev->type == VIR_DOMAIN_DEVICE_DISK)
             return 0;
@@ -400,6 +407,8 @@ testPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
         /* TPMs FD passing setup is special and handled separately */
         if (dev->type == VIR_DOMAIN_DEVICE_TPM)
             return 0;
+    } else {
+        devalias = "monitor";
     }
 
     switch ((virDomainChrType) chardev->type) {
@@ -416,20 +425,15 @@ testPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
         break;
 
     case VIR_DOMAIN_CHR_TYPE_FILE:
-        if (fcntl(1750, F_GETFD) != -1)
-            abort();
-        charpriv->fd = 1750;
+        fakesourcefd = 1750;
         break;
 
     case VIR_DOMAIN_CHR_TYPE_UNIX:
         if (chardev->data.nix.listen &&
-            virQEMUCapsGet(qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS_COMMANDLINE)) {
+            virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS_COMMANDLINE))
+            fakesourcefd = 1729;
 
-            if (fcntl(1729, F_GETFD) != -1)
-                abort();
-
-            charpriv->fd = 1729;
-        }
+        usefdset = false;
         break;
 
     case VIR_DOMAIN_CHR_TYPE_NMDM:
@@ -437,10 +441,29 @@ testPrepareHostBackendChardevOne(virDomainDeviceDef *dev,
         break;
     }
 
-    if (chardev->logfile) {
-        if (fcntl(1751, F_GETFD) != -1)
+    if (fakesourcefd != -1) {
+        if (fcntl(fakesourcefd, F_GETFD) != -1)
             abort();
-        charpriv->logfd = 1751;
+
+        if (usefdset)
+            charpriv->sourcefd = qemuFDPassNew(devalias, priv);
+        else
+            charpriv->sourcefd = qemuFDPassNewDirect(devalias, priv);
+
+        if (qemuFDPassAddFD(charpriv->sourcefd, &fakesourcefd, "-source") < 0)
+            return -1;
+    }
+
+    if (chardev->logfile) {
+        int fd = 1751;
+
+        if (fcntl(fd, F_GETFD) != -1)
+            abort();
+
+        charpriv->logfd = qemuFDPassNew(devalias, priv);
+
+        if (qemuFDPassAddFD(charpriv->logfd, &fd, "-log") < 0)
+            return -1;
     }
 
     return 0;
@@ -464,17 +487,11 @@ testCompareXMLToArgvCreateArgs(virQEMUDriver *drv,
 
     if (qemuDomainDeviceBackendChardevForeach(vm->def,
                                               testPrepareHostBackendChardevOne,
-                                              info->qemuCaps) < 0)
+                                              vm) < 0)
         return NULL;
 
-    if (virQEMUCapsGet(info->qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS_COMMANDLINE)) {
-        qemuDomainChrSourcePrivate *monpriv = QEMU_DOMAIN_CHR_SOURCE_PRIVATE(priv->monConfig);
-
-        if (fcntl(1729, F_GETFD) != -1)
-            abort();
-
-        monpriv->fd = 1729;
-    }
+    if (testPrepareHostBackendChardevOne(NULL, priv->monConfig, vm) < 0)
+        return NULL;
 
     for (i = 0; i < vm->def->ndisks; i++) {
         virDomainDiskDef *disk = vm->def->disks[i];