7 files changed, 15 insertions, 2 deletions
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index d4bedc2607..bf4b1cbfb8 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2149,6 +2149,7 @@ type_init(machvirt_machine_init);
 
 static void virt_machine_4_2_options(MachineClass *mc)
 {
+    compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);
 }
 DEFINE_VIRT_MACHINE_AS_LATEST(4, 2)
 
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 4c357d2928..d62e6377c2 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -991,7 +991,9 @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features,
         virtio_add_feature(&features, VIRTIO_BLK_F_SCSI);
     }
 
-    if (blk_enable_write_cache(s->blk)) {
+    if (blk_enable_write_cache(s->blk) ||
+        (s->conf.x_enable_wce_if_config_wce &&
+         virtio_has_feature(features, VIRTIO_BLK_F_CONFIG_WCE))) {
         virtio_add_feature(&features, VIRTIO_BLK_F_WCE);
     }
     if (blk_is_read_only(s->blk)) {
@@ -1270,6 +1272,8 @@ static Property virtio_blk_properties[] = {
                        conf.max_discard_sectors, BDRV_REQUEST_MAX_SECTORS),
     DEFINE_PROP_UINT32("max-write-zeroes-sectors", VirtIOBlock,
                        conf.max_write_zeroes_sectors, BDRV_REQUEST_MAX_SECTORS),
+    DEFINE_PROP_BOOL("x-enable-wce-if-config-wce", VirtIOBlock,
+                     conf.x_enable_wce_if_config_wce, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 1689ad3bf8..023548b4f3 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -27,6 +27,11 @@
 #include "hw/pci/pci.h"
 #include "hw/mem/nvdimm.h"
 
+GlobalProperty hw_compat_4_2[] = {
+    { "virtio-blk-device", "x-enable-wce-if-config-wce", "off" },
+};
+const size_t hw_compat_4_2_len = G_N_ELEMENTS(hw_compat_4_2);
+
 GlobalProperty hw_compat_4_1[] = {
     { "virtio-pci", "x-pcie-flr-init", "off" },
 };
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 1bd70d1abb..87aced0742 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -431,6 +431,7 @@ static void pc_i440fx_4_2_machine_options(MachineClass *m)
     m->alias = "pc";
     m->is_default = 1;
     pcmc->default_cpu_version = 1;
+    compat_props_add(m->compat_props, hw_compat_4_2, hw_compat_4_2_len);
 }
 
 DEFINE_I440FX_MACHINE(v4_2, "pc-i440fx-4.2", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 385e5cffb1..2608cd0062 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -354,6 +354,7 @@ static void pc_q35_4_2_machine_options(MachineClass *m)
     pc_q35_machine_options(m);
     m->alias = "q35";
     pcmc->default_cpu_version = 1;
+    compat_props_add(m->compat_props, hw_compat_4_2, hw_compat_4_2_len);
 }
 
 DEFINE_Q35_MACHINE(v4_2, "pc-q35-4.2", NULL,
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index e076f6023c..2ca92f2148 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4496,7 +4496,7 @@ static const TypeInfo spapr_machine_info = {
  */
 static void spapr_machine_4_2_class_options(MachineClass *mc)
 {
-    /* Defaults for the latest behaviour inherited from the base class */
+    compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);
 }
 
 DEFINE_SPAPR_MACHINE(4_2, "4.2", true);
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index d3edeef0ad..cb5fe4c84d 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -645,6 +645,7 @@ static void ccw_machine_4_2_instance_options(MachineState *machine)
 
 static void ccw_machine_4_2_class_options(MachineClass *mc)
 {
+    compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);
 }
 DEFINE_CCW_MACHINE(4_2, "4.2", true);