diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 32980e7330..6b4ed08499 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -668,6 +668,7 @@ VIR_ENUM_IMPL(virQEMUCaps,
 
               /* 425 */
               "blockdev.nbd.tls-hostname", /* QEMU_CAPS_BLOCKDEV_NBD_TLS_HOSTNAME */
+              "memory-backend-file.prealloc-threads", /* QEMU_CAPS_MEMORY_BACKEND_PREALLOC_THREADS */
     );
 
 
@@ -1766,6 +1767,7 @@ static struct virQEMUCapsStringFlags virQEMUCapsObjectPropsMemoryBackendFile[] =
      * released qemu versions. */
     { "x-use-canonical-path-for-ramblock-id", QEMU_CAPS_X_USE_CANONICAL_PATH_FOR_RAMBLOCK_ID },
     { "reserve", QEMU_CAPS_MEMORY_BACKEND_RESERVE },
+    { "prealloc-threads", QEMU_CAPS_MEMORY_BACKEND_PREALLOC_THREADS },
 };
 
 static struct virQEMUCapsStringFlags virQEMUCapsObjectPropsMemoryBackendMemfd[] = {
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 0a215a11d5..948029d60d 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -643,6 +643,7 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check */
 
     /* 425 */
     QEMU_CAPS_BLOCKDEV_NBD_TLS_HOSTNAME, /* tls hostname can be overriden for NBD clients */
+    QEMU_CAPS_MEMORY_BACKEND_PREALLOC_THREADS, /* -object memory-backend-*.prealloc-threads */
 
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;
diff --git a/tests/qemucapabilitiesdata/caps_5.0.0.aarch64.xml b/tests/qemucapabilitiesdata/caps_5.0.0.aarch64.xml
index 4c1a37104c..d188eab3fe 100644
--- a/tests/qemucapabilitiesdata/caps_5.0.0.aarch64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.0.0.aarch64.xml
@@ -178,6 +178,7 @@
   <flag name='input-linux'/>
   <flag name='query-display-options'/>
   <flag name='virtio-blk.queue-size'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>61700241</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.0.0.ppc64.xml b/tests/qemucapabilitiesdata/caps_5.0.0.ppc64.xml
index 070d0f2982..12592f457a 100644
--- a/tests/qemucapabilitiesdata/caps_5.0.0.ppc64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.0.0.ppc64.xml
@@ -186,6 +186,7 @@
   <flag name='input-linux'/>
   <flag name='query-display-options'/>
   <flag name='virtio-blk.queue-size'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>42900241</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.0.0.riscv64.xml b/tests/qemucapabilitiesdata/caps_5.0.0.riscv64.xml
index 286049a8a6..75c3a9b4fc 100644
--- a/tests/qemucapabilitiesdata/caps_5.0.0.riscv64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.0.0.riscv64.xml
@@ -170,6 +170,7 @@
   <flag name='input-linux'/>
   <flag name='query-display-options'/>
   <flag name='virtio-blk.queue-size'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>0</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.0.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_5.0.0.x86_64.xml
index f563d672b4..5927c48ee4 100644
--- a/tests/qemucapabilitiesdata/caps_5.0.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.0.0.x86_64.xml
@@ -219,6 +219,7 @@
   <flag name='input-linux'/>
   <flag name='query-display-options'/>
   <flag name='virtio-blk.queue-size'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100241</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.1.0.sparc.xml b/tests/qemucapabilitiesdata/caps_5.1.0.sparc.xml
index 58af90b29f..7de7c291f5 100644
--- a/tests/qemucapabilitiesdata/caps_5.1.0.sparc.xml
+++ b/tests/qemucapabilitiesdata/caps_5.1.0.sparc.xml
@@ -90,6 +90,7 @@
   <flag name='rotation-rate'/>
   <flag name='input-linux'/>
   <flag name='query-display-options'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5001000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>0</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml
index 2d0ef18147..e0291268b3 100644
--- a/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.1.0.x86_64.xml
@@ -222,6 +222,7 @@
   <flag name='query-display-options'/>
   <flag name='virtio-blk.queue-size'/>
   <flag name='virtio-mem-pci'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5001000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100242</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.2.0.aarch64.xml b/tests/qemucapabilitiesdata/caps_5.2.0.aarch64.xml
index 9f14d59efb..20a1a8154b 100644
--- a/tests/qemucapabilitiesdata/caps_5.2.0.aarch64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.2.0.aarch64.xml
@@ -184,6 +184,7 @@
   <flag name='virtio-blk.queue-size'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>61700243</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.2.0.ppc64.xml b/tests/qemucapabilitiesdata/caps_5.2.0.ppc64.xml
index e050514fc1..add2ded00a 100644
--- a/tests/qemucapabilitiesdata/caps_5.2.0.ppc64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.2.0.ppc64.xml
@@ -190,6 +190,7 @@
   <flag name='virtio-blk.queue-size'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>42900243</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.2.0.riscv64.xml b/tests/qemucapabilitiesdata/caps_5.2.0.riscv64.xml
index 4b123d4ce9..237d043e5d 100644
--- a/tests/qemucapabilitiesdata/caps_5.2.0.riscv64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.2.0.riscv64.xml
@@ -174,6 +174,7 @@
   <flag name='virtio-blk.queue-size'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>0</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.2.0.s390x.xml b/tests/qemucapabilitiesdata/caps_5.2.0.s390x.xml
index bc3c3c351a..57e40f8f86 100644
--- a/tests/qemucapabilitiesdata/caps_5.2.0.s390x.xml
+++ b/tests/qemucapabilitiesdata/caps_5.2.0.s390x.xml
@@ -141,6 +141,7 @@
   <flag name='virtio-blk.queue-size'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>39100243</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml
index 70ad14f548..7c65648c06 100644
--- a/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml
@@ -226,6 +226,7 @@
   <flag name='piix4.acpi-root-pci-hotplug'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>5002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100243</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.0.0.aarch64.xml b/tests/qemucapabilitiesdata/caps_6.0.0.aarch64.xml
index 9d501f29af..7557e6ad71 100644
--- a/tests/qemucapabilitiesdata/caps_6.0.0.aarch64.xml
+++ b/tests/qemucapabilitiesdata/caps_6.0.0.aarch64.xml
@@ -192,6 +192,7 @@
   <flag name='virtio-blk.queue-size'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>61700242</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.0.0.s390x.xml b/tests/qemucapabilitiesdata/caps_6.0.0.s390x.xml
index 02b24f5d7e..00009be3dc 100644
--- a/tests/qemucapabilitiesdata/caps_6.0.0.s390x.xml
+++ b/tests/qemucapabilitiesdata/caps_6.0.0.s390x.xml
@@ -149,6 +149,7 @@
   <flag name='virtio-blk.queue-size'/>
   <flag name='query-dirty-rate'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>39100242</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.0.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_6.0.0.x86_64.xml
index 8ea688f7a6..61d561dc69 100644
--- a/tests/qemucapabilitiesdata/caps_6.0.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_6.0.0.x86_64.xml
@@ -235,6 +235,7 @@
   <flag name='query-dirty-rate'/>
   <flag name='sev-inject-launch-secret'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6000000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100242</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.1.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_6.1.0.x86_64.xml
index ba1aecc37e..0b58210335 100644
--- a/tests/qemucapabilitiesdata/caps_6.1.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_6.1.0.x86_64.xml
@@ -239,6 +239,7 @@
   <flag name='rbd-encryption'/>
   <flag name='sev-inject-launch-secret'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6001000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100243</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.2.0.aarch64.xml b/tests/qemucapabilitiesdata/caps_6.2.0.aarch64.xml
index 17d563eb5b..d08b2c0213 100644
--- a/tests/qemucapabilitiesdata/caps_6.2.0.aarch64.xml
+++ b/tests/qemucapabilitiesdata/caps_6.2.0.aarch64.xml
@@ -203,6 +203,7 @@
   <flag name='query-dirty-rate'/>
   <flag name='rbd-encryption'/>
   <flag name='calc-dirty-rate'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6001050</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>61700244</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.2.0.ppc64.xml b/tests/qemucapabilitiesdata/caps_6.2.0.ppc64.xml
index 9fe9c27d14..8c52964ec0 100644
--- a/tests/qemucapabilitiesdata/caps_6.2.0.ppc64.xml
+++ b/tests/qemucapabilitiesdata/caps_6.2.0.ppc64.xml
@@ -201,6 +201,7 @@
   <flag name='sev-guest-kernel-hashes'/>
   <flag name='calc-dirty-rate'/>
   <flag name='dirtyrate-param.mode'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>42900244</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_6.2.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_6.2.0.x86_64.xml
index d77907af55..cdf72b9ebf 100644
--- a/tests/qemucapabilitiesdata/caps_6.2.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_6.2.0.x86_64.xml
@@ -241,6 +241,7 @@
   <flag name='sev-inject-launch-secret'/>
   <flag name='calc-dirty-rate'/>
   <flag name='dirtyrate-param.mode'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6002000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100244</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_7.0.0.ppc64.xml b/tests/qemucapabilitiesdata/caps_7.0.0.ppc64.xml
index 5d7f283a73..8aba3329ad 100644
--- a/tests/qemucapabilitiesdata/caps_7.0.0.ppc64.xml
+++ b/tests/qemucapabilitiesdata/caps_7.0.0.ppc64.xml
@@ -202,6 +202,7 @@
   <flag name='device.json+hotplug'/>
   <flag name='calc-dirty-rate'/>
   <flag name='dirtyrate-param.mode'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6002050</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>42900243</microcodeVersion>
diff --git a/tests/qemucapabilitiesdata/caps_7.0.0.x86_64.xml b/tests/qemucapabilitiesdata/caps_7.0.0.x86_64.xml
index 0f34a341af..5227e3ee0b 100644
--- a/tests/qemucapabilitiesdata/caps_7.0.0.x86_64.xml
+++ b/tests/qemucapabilitiesdata/caps_7.0.0.x86_64.xml
@@ -244,6 +244,7 @@
   <flag name='calc-dirty-rate'/>
   <flag name='dirtyrate-param.mode'/>
   <flag name='blockdev.nbd.tls-hostname'/>
+  <flag name='memory-backend-file.prealloc-threads'/>
   <version>6002050</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100243</microcodeVersion>