diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 6258c58ac9..204b6841ec 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -987,24 +987,26 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte, uint32_t level)
 static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState *s, uint8_t bus_num)
 {
     VTDBus *vtd_bus = s->vtd_as_by_bus_num[bus_num];
-    if (!vtd_bus) {
-        /*
-         * Iterate over the registered buses to find the one which
-         * currently hold this bus number, and update the bus_num
-         * lookup table:
-         */
-        GHashTableIter iter;
+    GHashTableIter iter;
 
-        g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
-        while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
-            if (pci_bus_num(vtd_bus->bus) == bus_num) {
-                s->vtd_as_by_bus_num[bus_num] = vtd_bus;
-                return vtd_bus;
-            }
-        }
-        vtd_bus = NULL;
+    if (vtd_bus) {
+        return vtd_bus;
     }
-    return vtd_bus;
+
+    /*
+     * Iterate over the registered buses to find the one which
+     * currently holds this bus number and update the bus_num
+     * lookup table.
+     */
+    g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
+    while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
+        if (pci_bus_num(vtd_bus->bus) == bus_num) {
+            s->vtd_as_by_bus_num[bus_num] = vtd_bus;
+            return vtd_bus;
+        }
+    }
+
+    return NULL;
 }
 
 /* Given the @iova, get relevant @slptep. @slpte_level will be the last level
diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c
index 0ba4e4dea4..f1cfe9d14a 100644
--- a/hw/pci-bridge/pcie_root_port.c
+++ b/hw/pci-bridge/pcie_root_port.c
@@ -94,7 +94,7 @@ static void rp_realize(PCIDevice *d, Error **errp)
 
     pcie_cap_arifwd_init(d);
     pcie_cap_deverr_init(d);
-    pcie_cap_slot_init(d, s->slot);
+    pcie_cap_slot_init(d, s);
     pcie_cap_root_init(d);
 
     pcie_chassis_create(s->chassis);
diff --git a/hw/pci-bridge/xio3130_downstream.c b/hw/pci-bridge/xio3130_downstream.c
index 153a4acad2..04aae72cd6 100644
--- a/hw/pci-bridge/xio3130_downstream.c
+++ b/hw/pci-bridge/xio3130_downstream.c
@@ -94,7 +94,7 @@ static void xio3130_downstream_realize(PCIDevice *d, Error **errp)
     }
     pcie_cap_flr_init(d);
     pcie_cap_deverr_init(d);
-    pcie_cap_slot_init(d, s->slot);
+    pcie_cap_slot_init(d, s);
     pcie_cap_arifwd_init(d);
 
     pcie_chassis_create(s->chassis);
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 08718188bb..0eb3a2a5d2 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -495,7 +495,7 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
 
 /* pci express slot for pci express root/downstream port
    PCI express capability slot registers */
-void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot)
+void pcie_cap_slot_init(PCIDevice *dev, PCIESlot *s)
 {
     uint32_t pos = dev->exp.exp_cap;
 
@@ -505,13 +505,16 @@ void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot)
     pci_long_test_and_clear_mask(dev->config + pos + PCI_EXP_SLTCAP,
                                  ~PCI_EXP_SLTCAP_PSN);
     pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCAP,
-                               (slot << PCI_EXP_SLTCAP_PSN_SHIFT) |
+                               (s->slot << PCI_EXP_SLTCAP_PSN_SHIFT) |
                                PCI_EXP_SLTCAP_EIP |
-                               PCI_EXP_SLTCAP_HPS |
-                               PCI_EXP_SLTCAP_HPC |
                                PCI_EXP_SLTCAP_PIP |
                                PCI_EXP_SLTCAP_AIP |
                                PCI_EXP_SLTCAP_ABP);
+    if (s->hotplug) {
+        pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCAP,
+                                   PCI_EXP_SLTCAP_HPS |
+                                   PCI_EXP_SLTCAP_HPC);
+    }
 
     if (dev->cap_present & QEMU_PCIE_SLTCAP_PCP) {
         pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCAP,
diff --git a/hw/pci/pcie_port.c b/hw/pci/pcie_port.c
index f8263cb306..eb563ad435 100644
--- a/hw/pci/pcie_port.c
+++ b/hw/pci/pcie_port.c
@@ -147,6 +147,7 @@ static const TypeInfo pcie_port_type_info = {
 static Property pcie_slot_props[] = {
     DEFINE_PROP_UINT8("chassis", PCIESlot, chassis, 0),
     DEFINE_PROP_UINT16("slot", PCIESlot, slot, 0),
+    DEFINE_PROP_BOOL("hotplug", PCIESlot, hotplug, true),
     DEFINE_PROP_END_OF_LIST()
 };
 
diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
index 66da96583b..9f9093e196 100644
--- a/hw/virtio/vhost-vsock.c
+++ b/hw/virtio/vhost-vsock.c
@@ -325,7 +325,7 @@ static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
     } else {
         vhostfd = open("/dev/vhost-vsock", O_RDWR);
         if (vhostfd < 0) {
-            error_setg_errno(errp, -errno,
+            error_setg_errno(errp, errno,
                              "vhost-vsock: failed to open vhost device");
             return;
         }
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 0d226dae10..01ebe12f28 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -290,7 +290,14 @@ static int vhost_dev_has_iommu(struct vhost_dev *dev)
 {
     VirtIODevice *vdev = dev->vdev;
 
-    return virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
+    /*
+     * For vhost, VIRTIO_F_IOMMU_PLATFORM means the backend support
+     * incremental memory mapping API via IOTLB API. For platform that
+     * does not have IOMMU, there's no need to enable this feature
+     * which may cause unnecessary IOTLB miss/update trnasactions.
+     */
+    return vdev->dma_as != &address_space_memory &&
+           virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
 }
 
 static void *vhost_memory_map(struct vhost_dev *dev, hwaddr addr,
@@ -765,6 +772,9 @@ static int vhost_dev_set_features(struct vhost_dev *dev,
     if (enable_log) {
         features |= 0x1ULL << VHOST_F_LOG_ALL;
     }
+    if (!vhost_dev_has_iommu(dev)) {
+        features &= ~(0x1ULL << VIRTIO_F_IOMMU_PLATFORM);
+    }
     r = dev->vhost_ops->vhost_set_features(dev, features);
     if (r < 0) {
         VHOST_OPS_DEBUG("vhost_set_features failed");
diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
index 7064875835..14c58ebdb6 100644
--- a/include/hw/pci/pcie.h
+++ b/include/hw/pci/pcie.h
@@ -104,7 +104,7 @@ void pcie_cap_deverr_reset(PCIDevice *dev);
 void pcie_cap_lnkctl_init(PCIDevice *dev);
 void pcie_cap_lnkctl_reset(PCIDevice *dev);
 
-void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
+void pcie_cap_slot_init(PCIDevice *dev, PCIESlot *s);
 void pcie_cap_slot_reset(PCIDevice *dev);
 void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slt_ctl, uint16_t *slt_sta);
 void pcie_cap_slot_write_config(PCIDevice *dev,
diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h
index 4b3d254b08..caae57573b 100644
--- a/include/hw/pci/pcie_port.h
+++ b/include/hw/pci/pcie_port.h
@@ -55,6 +55,9 @@ struct PCIESlot {
 
     /* Disable ACS (really for a pcie_root_port) */
     bool        disable_acs;
+
+    /* Indicates whether hot-plug is enabled on the slot */
+    bool        hotplug;
     QLIST_ENTRY(PCIESlot) next;
 };