diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index 179c7dc..1b228ad 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -366,6 +366,27 @@ static uint8_t assigned_dev_pci_read_byte(PCIDevice *d, int pos)
     return (uint8_t)assigned_dev_pci_read(d, pos, 1);
 }
 
+static void assigned_dev_pci_write(PCIDevice *d, int pos, uint32_t val, int len)
+{
+    AssignedDevice *pci_dev = container_of(d, AssignedDevice, dev);
+    ssize_t ret;
+    int fd = pci_dev->real_device.config_fd;
+
+again:
+    ret = pwrite(fd, &val, len, pos);
+    if (ret != len) {
+	if ((ret < 0) && (errno == EINTR || errno == EAGAIN))
+	    goto again;
+
+	fprintf(stderr, "%s: pwrite failed, ret = %zd errno = %d\n",
+		__func__, ret, errno);
+
+	exit(1);
+    }
+
+    return;
+}
+
 static uint8_t pci_find_cap_offset(PCIDevice *d, uint8_t cap)
 {
     int id;
@@ -1244,37 +1265,75 @@ static void assigned_dev_update_msix(PCIDevice *pci_dev, unsigned int ctrl_pos)
 #endif
 #endif
 
+static uint32_t assigned_device_pci_cap_read_config(PCIDevice *pci_dev,
+                                                    uint8_t cap_id,
+                                                    uint32_t address, int len)
+{
+    uint8_t cap;
+
+    switch (cap_id) {
+
+    case PCI_CAP_ID_VPD:
+        cap = pci_find_capability(pci_dev, cap_id);
+        if (address - cap >= PCI_CAP_FLAGS) {
+            return assigned_dev_pci_read(pci_dev, address, len);
+        }
+        break;
+
+    case PCI_CAP_ID_VNDR:
+        cap = pci_find_capability(pci_dev, cap_id);
+        if (address - cap > PCI_CAP_FLAGS) {
+            return assigned_dev_pci_read(pci_dev, address, len);
+        }
+        break;
+    }
+
+    return pci_default_cap_read_config(pci_dev, cap_id, address, len);
+}
+
 static void assigned_device_pci_cap_write_config(PCIDevice *pci_dev,
                                                  uint8_t cap_id,
                                                  uint32_t address,
                                                  uint32_t val, int len)
 {
+    uint8_t cap;
+
     pci_default_cap_write_config(pci_dev, cap_id, address, val, len);
 
     switch (cap_id) {
 #ifdef KVM_CAP_IRQ_ROUTING
     case PCI_CAP_ID_MSI:
 #ifdef KVM_CAP_DEVICE_MSI
-        {
-            uint8_t cap = pci_find_capability(pci_dev, cap_id);
-            if (ranges_overlap(address - cap, len, PCI_MSI_FLAGS, 1)) {
-                assigned_dev_update_msi(pci_dev, cap + PCI_MSI_FLAGS);
-            }
+        cap = pci_find_capability(pci_dev, cap_id);
+        if (ranges_overlap(address - cap, len, PCI_MSI_FLAGS, 1)) {
+            assigned_dev_update_msi(pci_dev, cap + PCI_MSI_FLAGS);
         }
 #endif
         break;
 
     case PCI_CAP_ID_MSIX:
 #ifdef KVM_CAP_DEVICE_MSIX
-        {
-            uint8_t cap = pci_find_capability(pci_dev, cap_id);
-            if (ranges_overlap(address - cap, len, PCI_MSIX_FLAGS + 1, 1)) {
-                assigned_dev_update_msix(pci_dev, cap + PCI_MSIX_FLAGS);
-            }
+        cap = pci_find_capability(pci_dev, cap_id);
+        if (ranges_overlap(address - cap, len, PCI_MSIX_FLAGS + 1, 1)) {
+            assigned_dev_update_msix(pci_dev, cap + PCI_MSIX_FLAGS);
         }
 #endif
         break;
 #endif
+
+    case PCI_CAP_ID_VPD:
+        cap = pci_find_capability(pci_dev, cap_id);
+        if (address - cap >= PCI_CAP_FLAGS) {
+            assigned_dev_pci_write(pci_dev, address, val, len);
+        }
+        break;
+
+    case PCI_CAP_ID_VNDR:
+        cap = pci_find_capability(pci_dev, cap_id);
+        if (address - cap > PCI_CAP_FLAGS) {
+            assigned_dev_pci_write(pci_dev, address, val, len);
+        }
+        break;
     }
     return;
 }
@@ -1340,6 +1399,84 @@ static int assigned_device_pci_cap_init(PCIDevice *pci_dev)
 #endif
 #endif
 
+    /* Minimal PM support, make the state bits writable so the guest
+     * thinks it's doing something. */
+    if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_PM))) {
+        uint16_t pmc, pmcsr;
+        pci_add_capability_at_offset(pci_dev, PCI_CAP_ID_PM, pos,
+                                     PCI_PM_SIZEOF);
+
+        pmc = pci_get_word(pci_dev->config + pos + PCI_CAP_FLAGS);
+        pmc &= (PCI_PM_CAP_VER_MASK | PCI_PM_CAP_DSI);
+        pci_set_word(pci_dev->config + pos + PCI_CAP_FLAGS, pmc);
+
+        pmcsr = pci_get_word(pci_dev->config + pos + PCI_PM_CTRL);
+        pmcsr &= (PCI_PM_CTRL_STATE_MASK);
+        pmcsr |= PCI_PM_CTRL_NO_SOFT_RST;
+        pci_set_word(pci_dev->config + pos + PCI_PM_CTRL, pmcsr);
+
+        pci_set_word(pci_dev->wmask + pos + PCI_PM_CTRL,
+                     PCI_PM_CTRL_STATE_MASK);
+    }
+
+    if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_EXP))) {
+        uint16_t devctl, lnkcap, lnksta;
+
+        pci_add_capability_at_offset(pci_dev, PCI_CAP_ID_EXP, pos, 0x40);
+
+        devctl = pci_get_word(pci_dev->config + pos + PCI_EXP_DEVCTL);
+        devctl = (devctl & (PCI_EXP_DEVCTL_READRQ | PCI_EXP_DEVCTL_PAYLOAD)) |
+                  PCI_EXP_DEVCTL_RELAX_EN | PCI_EXP_DEVCTL_NOSNOOP_EN;
+        pci_set_word(pci_dev->config + pos + PCI_EXP_DEVCTL, devctl);
+        devctl = PCI_EXP_DEVCTL_BCR_FLR | PCI_EXP_DEVCTL_AUX_PME;
+        pci_set_word(pci_dev->wmask + pos + PCI_EXP_DEVCTL, ~devctl);
+
+        lnkcap = pci_get_word(pci_dev->config + pos + PCI_EXP_LNKCAP);
+        lnkcap &= (PCI_EXP_LNKCAP_SLS | PCI_EXP_LNKCAP_MLW |
+                   PCI_EXP_LNKCAP_ASPMS | PCI_EXP_LNKCAP_L0SEL |
+                   PCI_EXP_LNKCAP_L1EL);
+        pci_set_word(pci_dev->config + pos + PCI_EXP_LNKCAP, lnkcap);
+
+        pci_set_word(pci_dev->wmask + pos + PCI_EXP_LNKCAP,
+                     PCI_EXP_LNKCTL_ASPMC | PCI_EXP_LNKCTL_RCB |
+                     PCI_EXP_LNKCTL_CCC | PCI_EXP_LNKCTL_ES |
+                     PCI_EXP_LNKCTL_CLKREQ_EN | PCI_EXP_LNKCTL_HAWD);
+        
+        lnksta = pci_get_word(pci_dev->config + pos + PCI_EXP_LNKSTA);
+        lnksta &= (PCI_EXP_LNKSTA_CLS | PCI_EXP_LNKSTA_NLW);
+        pci_set_word(pci_dev->config + pos + PCI_EXP_LNKSTA, lnksta);
+
+        pci_set_word(pci_dev->wmask + pos + 0x28, 0x1f);
+        pci_set_word(pci_dev->wmask + pos + 0x30, 0xfbf);
+    }
+
+    if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_VPD))) {
+        pci_add_capability_at_offset(pci_dev, PCI_CAP_ID_VPD, pos, 0x8);
+    }
+
+    if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_VNDR))) {
+        uint8_t len = pci_get_byte(pci_dev->config + pos + PCI_CAP_FLAGS);
+        pci_add_capability_at_offset(pci_dev, PCI_CAP_ID_VNDR, pos, len);
+    }
+
+    if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_PCIX))) {
+        uint16_t cmd;
+        uint32_t status;
+
+        pci_add_capability_at_offset(pci_dev, PCI_CAP_ID_PCIX, pos, 0x8);
+
+        cmd = pci_get_word(pci_dev->config + pos + PCI_X_CMD);
+        cmd &= (PCI_X_CMD_DPERR_E | PCI_X_CMD_ERO | PCI_X_CMD_MAX_READ |
+                PCI_X_CMD_MAX_SPLIT);
+        pci_set_word(pci_dev->config + pos + PCI_X_CMD, cmd);
+
+        status = pci_get_long(pci_dev->config + pos + PCI_X_STATUS);
+        status &= ~(PCI_X_STATUS_BUS | PCI_X_STATUS_DEVFN);
+        status |= (pci_bus_num(pci_dev->bus) << 8) | pci_dev->devfn;
+        status &= ~(PCI_X_STATUS_SPL_DISC | PCI_X_STATUS_UNX_SPL |
+                    PCI_X_STATUS_SPL_ERR);
+        pci_set_long(pci_dev->config + pos + PCI_X_STATUS, status);
+    }
     return 0;
 }
 
@@ -1466,7 +1603,8 @@ static int assigned_initfn(struct PCIDevice *pci_dev)
     dev->h_busnr = dev->host.bus;
     dev->h_devfn = PCI_DEVFN(dev->host.dev, dev->host.func);
 
-    pci_register_capability_handlers(pci_dev, NULL,
+    pci_register_capability_handlers(pci_dev,
+                                     assigned_device_pci_cap_read_config,
                                      assigned_device_pci_cap_write_config);
 
     if (assigned_device_pci_cap_init(pci_dev) < 0)
