diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 2785127037..5f12ac1200 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -4374,6 +4374,7 @@ static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev)
     NVME_CAP_SET_CSS(n->bar.cap, NVME_CAP_CSS_CSI_SUPP);
     NVME_CAP_SET_CSS(n->bar.cap, NVME_CAP_CSS_ADMIN_ONLY);
     NVME_CAP_SET_MPSMAX(n->bar.cap, 4);
+    NVME_CAP_SET_CMBS(n->bar.cap, n->params.cmb_size_mb ? 1 : 0);
 
     n->bar.vs = NVME_SPEC_VER;
     n->bar.intmc = n->bar.intms = 0;
diff --git a/include/block/nvme.h b/include/block/nvme.h
index 854fb2abb6..151921da21 100644
--- a/include/block/nvme.h
+++ b/include/block/nvme.h
@@ -36,6 +36,7 @@ enum NvmeCapShift {
     CAP_MPSMIN_SHIFT   = 48,
     CAP_MPSMAX_SHIFT   = 52,
     CAP_PMR_SHIFT      = 56,
+    CAP_CMB_SHIFT      = 57,
 };
 
 enum NvmeCapMask {
@@ -49,6 +50,7 @@ enum NvmeCapMask {
     CAP_MPSMIN_MASK    = 0xf,
     CAP_MPSMAX_MASK    = 0xf,
     CAP_PMR_MASK       = 0x1,
+    CAP_CMB_MASK       = 0x1,
 };
 
 #define NVME_CAP_MQES(cap)  (((cap) >> CAP_MQES_SHIFT)   & CAP_MQES_MASK)
@@ -79,9 +81,11 @@ enum NvmeCapMask {
 #define NVME_CAP_SET_MPSMIN(cap, val) (cap |= (uint64_t)(val & CAP_MPSMIN_MASK)\
                                                            << CAP_MPSMIN_SHIFT)
 #define NVME_CAP_SET_MPSMAX(cap, val) (cap |= (uint64_t)(val & CAP_MPSMAX_MASK)\
-                                                            << CAP_MPSMAX_SHIFT)
-#define NVME_CAP_SET_PMRS(cap, val) (cap |= (uint64_t)(val & CAP_PMR_MASK)\
-                                                            << CAP_PMR_SHIFT)
+                                                           << CAP_MPSMAX_SHIFT)
+#define NVME_CAP_SET_PMRS(cap, val)   (cap |= (uint64_t)(val & CAP_PMR_MASK)   \
+                                                           << CAP_PMR_SHIFT)
+#define NVME_CAP_SET_CMBS(cap, val)   (cap |= (uint64_t)(val & CAP_CMB_MASK)   \
+                                                           << CAP_CMB_SHIFT)
 
 enum NvmeCapCss {
     NVME_CAP_CSS_NVM        = 1 << 0,