diff --git a/include/hw/pci/pcie_sriov.h b/include/hw/pci/pcie_sriov.h
index 4b1133f79e15..793d03c5f12e 100644
--- a/include/hw/pci/pcie_sriov.h
+++ b/include/hw/pci/pcie_sriov.h
@@ -16,7 +16,6 @@
 #include "hw/pci/pci.h"
 
 struct PCIESriovPF {
-    uint16_t num_vfs;   /* Number of virtual functions created */
     uint8_t vf_bar_type[PCI_NUM_REGIONS];   /* Store type for each VF bar */
     PCIDevice **vf;     /* Pointer to an array of num_vfs VF devices */
 };
diff --git a/hw/pci/pcie_sriov.c b/hw/pci/pcie_sriov.c
index 8710ee95b26d..fb48c1a18c9a 100644
--- a/hw/pci/pcie_sriov.c
+++ b/hw/pci/pcie_sriov.c
@@ -44,7 +44,6 @@ bool pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset,
     pcie_add_capability(dev, PCI_EXT_CAP_ID_SRIOV, 1,
                         offset, PCI_EXT_CAP_SRIOV_SIZEOF);
     dev->exp.sriov_cap = offset;
-    dev->exp.sriov_pf.num_vfs = 0;
     dev->exp.sriov_pf.vf = NULL;
 
     pci_set_word(cfg + PCI_SRIOV_VF_OFFSET, vf_offset);
@@ -173,6 +172,12 @@ void pcie_sriov_vf_register_bar(PCIDevice *dev, int region_num,
     }
 }
 
+static void clear_ctrl_vfe(PCIDevice *dev)
+{
+    uint8_t *ctrl = dev->config + dev->exp.sriov_cap + PCI_SRIOV_CTRL;
+    pci_set_word(ctrl, pci_get_word(ctrl) & ~PCI_SRIOV_CTRL_VFE);
+}
+
 static void register_vfs(PCIDevice *dev)
 {
     uint16_t num_vfs;
@@ -182,6 +187,7 @@ static void register_vfs(PCIDevice *dev)
     assert(sriov_cap > 0);
     num_vfs = pci_get_word(dev->config + sriov_cap + PCI_SRIOV_NUM_VF);
     if (num_vfs > pci_get_word(dev->config + sriov_cap + PCI_SRIOV_TOTAL_VF)) {
+        clear_ctrl_vfe(dev);
         return;
     }
 
@@ -190,20 +196,18 @@ static void register_vfs(PCIDevice *dev)
     for (i = 0; i < num_vfs; i++) {
         pci_set_enabled(dev->exp.sriov_pf.vf[i], true);
     }
-    dev->exp.sriov_pf.num_vfs = num_vfs;
 }
 
 static void unregister_vfs(PCIDevice *dev)
 {
-    uint16_t num_vfs = dev->exp.sriov_pf.num_vfs;
     uint16_t i;
+    uint8_t *cfg = dev->config + dev->exp.sriov_cap;
 
     trace_sriov_unregister_vfs(dev->name, PCI_SLOT(dev->devfn),
-                               PCI_FUNC(dev->devfn), num_vfs);
-    for (i = 0; i < num_vfs; i++) {
+                               PCI_FUNC(dev->devfn));
+    for (i = 0; i < pci_get_word(cfg + PCI_SRIOV_TOTAL_VF); i++) {
         pci_set_enabled(dev->exp.sriov_pf.vf[i], false);
     }
-    dev->exp.sriov_pf.num_vfs = 0;
 }
 
 void pcie_sriov_config_write(PCIDevice *dev, uint32_t address,
@@ -229,6 +233,9 @@ void pcie_sriov_config_write(PCIDevice *dev, uint32_t address,
         } else {
             unregister_vfs(dev);
         }
+    } else if (range_covers_byte(off, len, PCI_SRIOV_NUM_VF)) {
+        clear_ctrl_vfe(dev);
+        unregister_vfs(dev);
     }
 }
 
@@ -291,7 +298,7 @@ PCIDevice *pcie_sriov_get_pf(PCIDevice *dev)
 PCIDevice *pcie_sriov_get_vf_at_index(PCIDevice *dev, int n)
 {
     assert(!pci_is_vf(dev));
-    if (n < dev->exp.sriov_pf.num_vfs) {
+    if (n < pcie_sriov_num_vfs(dev)) {
         return dev->exp.sriov_pf.vf[n];
     }
     return NULL;
@@ -299,5 +306,10 @@ PCIDevice *pcie_sriov_get_vf_at_index(PCIDevice *dev, int n)
 
 uint16_t pcie_sriov_num_vfs(PCIDevice *dev)
 {
-    return dev->exp.sriov_pf.num_vfs;
+    uint16_t sriov_cap = dev->exp.sriov_cap;
+    uint8_t *cfg = dev->config + sriov_cap;
+
+    return sriov_cap &&
+           (pci_get_word(cfg + PCI_SRIOV_CTRL) & PCI_SRIOV_CTRL_VFE) ?
+           pci_get_word(cfg + PCI_SRIOV_NUM_VF) : 0;
 }
diff --git a/hw/pci/trace-events b/hw/pci/trace-events
index 42430869ce05..b30e31619787 100644
--- a/hw/pci/trace-events
+++ b/hw/pci/trace-events
@@ -14,5 +14,5 @@ msix_write_config(char *name, bool enabled, bool masked) "dev %s enabled %d mask
 
 # hw/pci/pcie_sriov.c
 sriov_register_vfs(const char *name, int slot, int function, int num_vfs) "%s %02x:%x: creating %d vf devs"
-sriov_unregister_vfs(const char *name, int slot, int function, int num_vfs) "%s %02x:%x: Unregistering %d vf devs"
+sriov_unregister_vfs(const char *name, int slot, int function) "%s %02x:%x: Unregistering vf devs"
 sriov_config_write(const char *name, int slot, int fun, uint32_t offset, uint32_t val, uint32_t len) "%s %02x:%x: sriov offset 0x%x val 0x%x len %d"
