diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index 9e31ab2da4..39b1f74442 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -104,6 +104,24 @@ static void acpi_set_pci_info(void)
     }
 }
 
+static void acpi_pcihp_disable_root_bus(void)
+{
+    static bool root_hp_disabled;
+    PCIBus *bus;
+
+    if (root_hp_disabled) {
+        return;
+    }
+
+    bus = find_i440fx();
+    if (bus) {
+        /* setting the hotplug handler to NULL makes the bus non-hotpluggable */
+        qbus_set_hotplug_handler(BUS(bus), NULL);
+    }
+    root_hp_disabled = true;
+    return;
+}
+
 static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque)
 {
     AcpiPciHpFind *find = opaque;
@@ -209,8 +227,11 @@ static void acpi_pcihp_update(AcpiPciHpState *s)
     }
 }
 
-void acpi_pcihp_reset(AcpiPciHpState *s)
+void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off)
 {
+    if (acpihp_root_off) {
+        acpi_pcihp_disable_root_bus();
+    }
     acpi_set_pci_info();
     acpi_pcihp_update(s);
 }
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 26bac4f16c..e6163bb6ce 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -78,6 +78,7 @@ typedef struct PIIX4PMState {
 
     AcpiPciHpState acpi_pci_hotplug;
     bool use_acpi_hotplug_bridge;
+    bool use_acpi_root_pci_hotplug;
 
     uint8_t disable_s3;
     uint8_t disable_s4;
@@ -324,7 +325,7 @@ static void piix4_pm_reset(DeviceState *dev)
         pci_conf[0x5B] = 0x02;
     }
     pm_io_space_update(s);
-    acpi_pcihp_reset(&s->acpi_pci_hotplug);
+    acpi_pcihp_reset(&s->acpi_pci_hotplug, !s->use_acpi_root_pci_hotplug);
 }
 
 static void piix4_pm_powerdown_req(Notifier *n, void *opaque)
@@ -635,6 +636,8 @@ static Property piix4_pm_properties[] = {
     DEFINE_PROP_UINT8(ACPI_PM_PROP_S4_VAL, PIIX4PMState, s4_val, 2),
     DEFINE_PROP_BOOL("acpi-pci-hotplug-with-bridge-support", PIIX4PMState,
                      use_acpi_hotplug_bridge, true),
+    DEFINE_PROP_BOOL("acpi-root-pci-hotplug", PIIX4PMState,
+                     use_acpi_root_pci_hotplug, true),
     DEFINE_PROP_BOOL("memory-hotplug-support", PIIX4PMState,
                      acpi_memory_hotplug.is_enabled, true),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 91f0df7b13..0a482ff6f7 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -170,7 +170,7 @@ static void acpi_dsdt_add_pci(Aml *scope, const MemMapEntry *memmap,
     aml_append(dev, aml_name_decl("_CID", aml_string("PNP0A03")));
     aml_append(dev, aml_name_decl("_SEG", aml_int(0)));
     aml_append(dev, aml_name_decl("_BBN", aml_int(0)));
-    aml_append(dev, aml_name_decl("_UID", aml_string("PCI0")));
+    aml_append(dev, aml_name_decl("_UID", aml_int(0)));
     aml_append(dev, aml_name_decl("_STR", aml_unicode("PCIe 0 Device")));
     aml_append(dev, aml_name_decl("_CCA", aml_int(1)));
 
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index a00b854736..39aec42dae 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -420,6 +420,9 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
+        s->num_queues = 1;
+    }
     if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
         error_setg(errp, "vhost-user-blk: invalid number of IO queues");
         return;
@@ -531,7 +534,8 @@ static const VMStateDescription vmstate_vhost_user_blk = {
 
 static Property vhost_user_blk_properties[] = {
     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
-    DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues, 1),
+    DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
+                       VHOST_USER_BLK_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 413783693c..2204ba149e 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1147,6 +1147,9 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
         error_setg(errp, "Device needs media, but drive is empty");
         return;
     }
+    if (conf->num_queues == VIRTIO_BLK_AUTO_NUM_QUEUES) {
+        conf->num_queues = 1;
+    }
     if (!conf->num_queues) {
         error_setg(errp, "num-queues property must be larger than 0");
         return;
@@ -1281,7 +1284,8 @@ static Property virtio_blk_properties[] = {
 #endif
     DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
                     true),
-    DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1),
+    DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues,
+                       VIRTIO_BLK_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 256),
     DEFINE_PROP_BOOL("seg-max-adjust", VirtIOBlock, conf.seg_max_adjust, true),
     DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD,
diff --git a/hw/core/machine.c b/hw/core/machine.c
index cf5f2dfaeb..ea26d61237 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -28,7 +28,13 @@
 #include "hw/mem/nvdimm.h"
 #include "migration/vmstate.h"
 
-GlobalProperty hw_compat_5_1[] = {};
+GlobalProperty hw_compat_5_1[] = {
+    { "vhost-scsi", "num_queues", "1"},
+    { "vhost-user-blk", "num-queues", "1"},
+    { "vhost-user-scsi", "num_queues", "1"},
+    { "virtio-blk-device", "num-queues", "1"},
+    { "virtio-scsi-device", "num_queues", "1"},
+};
 const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
 
 GlobalProperty hw_compat_5_0[] = {
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b7bcbbbb2a..7a5a8b3521 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1497,7 +1497,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         dev = aml_device("PCI0");
         aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
-        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
+        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
         aml_append(sb_scope, dev);
         aml_append(dsdt, sb_scope);
 
@@ -1512,7 +1512,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
         aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
-        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
+        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
         aml_append(dev, build_q35_osc_method());
         aml_append(sb_scope, dev);
         aml_append(dsdt, sb_scope);
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index 13b05af29b..a83ffeefc8 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -270,7 +270,8 @@ static Property vhost_scsi_properties[] = {
     DEFINE_PROP_STRING("vhostfd", VirtIOSCSICommon, conf.vhostfd),
     DEFINE_PROP_STRING("wwpn", VirtIOSCSICommon, conf.wwpn),
     DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
-    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
+    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
+                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
                        128),
     DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSICommon, conf.seg_max_adjust,
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index f2e524438a..7c0631656c 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -114,7 +114,7 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
         goto free_virtio;
     }
 
-    vsc->dev.nvqs = 2 + vs->conf.num_queues;
+    vsc->dev.nvqs = VIRTIO_SCSI_VQ_NUM_FIXED + vs->conf.num_queues;
     vsc->dev.vqs = g_new0(struct vhost_virtqueue, vsc->dev.nvqs);
     vsc->dev.vq_index = 0;
     vsc->dev.backend_features = 0;
@@ -162,7 +162,8 @@ static void vhost_user_scsi_unrealize(DeviceState *dev)
 static Property vhost_user_scsi_properties[] = {
     DEFINE_PROP_CHR("chardev", VirtIOSCSICommon, conf.chardev),
     DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
-    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
+    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
+                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
                        128),
     DEFINE_PROP_UINT32("max_sectors", VirtIOSCSICommon, conf.max_sectors,
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index b49775269e..3a71ea7097 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -191,7 +191,7 @@ static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
     VirtIOSCSIReq *req = sreq->hba_private;
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(req->dev);
     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
-    uint32_t n = virtio_get_queue_index(req->vq) - 2;
+    uint32_t n = virtio_get_queue_index(req->vq) - VIRTIO_SCSI_VQ_NUM_FIXED;
 
     assert(n < vs->conf.num_queues);
     qemu_put_be32s(f, &n);
@@ -891,11 +891,15 @@ void virtio_scsi_common_realize(DeviceState *dev,
     virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI,
                 sizeof(VirtIOSCSIConfig));
 
+    if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        s->conf.num_queues = 1;
+    }
     if (s->conf.num_queues == 0 ||
-            s->conf.num_queues > VIRTIO_QUEUE_MAX - 2) {
+            s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
                          "must be a positive integer less than %d.",
-                   s->conf.num_queues, VIRTIO_QUEUE_MAX - 2);
+                   s->conf.num_queues,
+                   VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED);
         virtio_cleanup(vdev);
         return;
     }
@@ -963,7 +967,8 @@ static void virtio_scsi_device_unrealize(DeviceState *dev)
 }
 
 static Property virtio_scsi_properties[] = {
-    DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1),
+    DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
+                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
                                          parent_obj.conf.virtqueue_size, 256),
     DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
index f560826904..7cc950b41c 100644
--- a/hw/smbios/smbios.c
+++ b/hw/smbios/smbios.c
@@ -92,9 +92,21 @@ static struct {
     const char *manufacturer, *version, *serial, *asset, *sku;
 } type3;
 
+/*
+ * SVVP requires max_speed and current_speed to be set and not being
+ * 0 which counts as unknown (SMBIOS 3.1.0/Table 21). Set the
+ * default value to 2000MHz as we did before.
+ */
+#define DEFAULT_CPU_SPEED 2000
+
 static struct {
     const char *sock_pfx, *manufacturer, *version, *serial, *asset, *part;
-} type4;
+    uint64_t max_speed;
+    uint64_t current_speed;
+} type4 = {
+    .max_speed = DEFAULT_CPU_SPEED,
+    .current_speed = DEFAULT_CPU_SPEED
+};
 
 static struct {
     size_t nvalues;
@@ -272,6 +284,14 @@ static const QemuOptDesc qemu_smbios_type4_opts[] = {
         .name = "version",
         .type = QEMU_OPT_STRING,
         .help = "version number",
+    },{
+        .name = "max-speed",
+        .type = QEMU_OPT_NUMBER,
+        .help = "max speed in MHz",
+    },{
+        .name = "current-speed",
+        .type = QEMU_OPT_NUMBER,
+        .help = "speed at system boot in MHz",
     },{
         .name = "serial",
         .type = QEMU_OPT_STRING,
@@ -586,9 +606,8 @@ static void smbios_build_type_4_table(MachineState *ms, unsigned instance)
     SMBIOS_TABLE_SET_STR(4, processor_version_str, type4.version);
     t->voltage = 0;
     t->external_clock = cpu_to_le16(0); /* Unknown */
-    /* SVVP requires max_speed and current_speed to not be unknown. */
-    t->max_speed = cpu_to_le16(2000); /* 2000 MHz */
-    t->current_speed = cpu_to_le16(2000); /* 2000 MHz */
+    t->max_speed = cpu_to_le16(type4.max_speed);
+    t->current_speed = cpu_to_le16(type4.current_speed);
     t->status = 0x41; /* Socket populated, CPU enabled */
     t->processor_upgrade = 0x01; /* Other */
     t->l1_cache_handle = cpu_to_le16(0xFFFF); /* N/A */
@@ -1116,6 +1135,15 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
             save_opt(&type4.serial, opts, "serial");
             save_opt(&type4.asset, opts, "asset");
             save_opt(&type4.part, opts, "part");
+            type4.max_speed = qemu_opt_get_number(opts, "max-speed",
+                                                  DEFAULT_CPU_SPEED);
+            type4.current_speed = qemu_opt_get_number(opts, "current-speed",
+                                                      DEFAULT_CPU_SPEED);
+            if (type4.max_speed > UINT16_MAX ||
+                type4.current_speed > UINT16_MAX) {
+                error_setg(errp, "SMBIOS CPU speed is too large (> %d)",
+                           UINT16_MAX);
+            }
             return;
         case 11:
             if (!qemu_opts_validate(opts, qemu_smbios_type11_opts, errp)) {
diff --git a/hw/virtio/vhost-scsi-pci.c b/hw/virtio/vhost-scsi-pci.c
index 095af23f3f..a6bb0dc60d 100644
--- a/hw/virtio/vhost-scsi-pci.c
+++ b/hw/virtio/vhost-scsi-pci.c
@@ -47,10 +47,15 @@ static void vhost_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VHostSCSIPCI *dev = VHOST_SCSI_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
+    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
+
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues + 3;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/vhost-user-blk-pci.c b/hw/virtio/vhost-user-blk-pci.c
index 4f5d5cbf44..a62a71e067 100644
--- a/hw/virtio/vhost-user-blk-pci.c
+++ b/hw/virtio/vhost-user-blk-pci.c
@@ -54,6 +54,10 @@ static void vhost_user_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
 
+    if (dev->vdev.num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
+        dev->vdev.num_queues = virtio_pci_optimal_num_queues(0);
+    }
+
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
         vpci_dev->nvectors = dev->vdev.num_queues + 1;
     }
diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
index 4705cd54e8..25e97ca54e 100644
--- a/hw/virtio/vhost-user-scsi-pci.c
+++ b/hw/virtio/vhost-user-scsi-pci.c
@@ -53,10 +53,15 @@ static void vhost_user_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VHostUserSCSIPCI *dev = VHOST_USER_SCSI_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
+    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
+
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues + 3;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/virtio-blk-pci.c b/hw/virtio/virtio-blk-pci.c
index 849cc7dfd8..37c6e0aeb4 100644
--- a/hw/virtio/virtio-blk-pci.c
+++ b/hw/virtio/virtio-blk-pci.c
@@ -50,9 +50,14 @@ static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
+    VirtIOBlkConf *conf = &dev->vdev.conf;
+
+    if (conf->num_queues == VIRTIO_BLK_AUTO_NUM_QUEUES) {
+        conf->num_queues = virtio_pci_optimal_num_queues(0);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = dev->vdev.conf.num_queues + 1;
+        vpci_dev->nvectors = conf->num_queues + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index ccdf54e81c..fc69570dcc 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -19,6 +19,7 @@
 
 #include "exec/memop.h"
 #include "standard-headers/linux/virtio_pci.h"
+#include "hw/boards.h"
 #include "hw/virtio/virtio.h"
 #include "migration/qemu-file-types.h"
 #include "hw/pci/pci.h"
@@ -2058,6 +2059,37 @@ void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t)
     g_free(base_name);
 }
 
+unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues)
+{
+    /*
+     * 1:1 vq to vCPU mapping is ideal because the same vCPU that submitted
+     * virtqueue buffers can handle their completion. When a different vCPU
+     * handles completion it may need to IPI the vCPU that submitted the
+     * request and this adds overhead.
+     *
+     * Virtqueues consume guest RAM and MSI-X vectors. This is wasteful in
+     * guests with very many vCPUs and a device that is only used by a few
+     * vCPUs. Unfortunately optimizing that case requires manual pinning inside
+     * the guest, so those users might as well manually set the number of
+     * queues. There is no upper limit that can be applied automatically and
+     * doing so arbitrarily would result in a sudden performance drop once the
+     * threshold number of vCPUs is exceeded.
+     */
+    unsigned num_queues = current_machine->smp.cpus;
+
+    /*
+     * The maximum number of MSI-X vectors is PCI_MSIX_FLAGS_QSIZE + 1, but the
+     * config change interrupt and the fixed virtqueues must be taken into
+     * account too.
+     */
+    num_queues = MIN(num_queues, PCI_MSIX_FLAGS_QSIZE - fixed_queues);
+
+    /*
+     * There is a limit to how many virtqueues a device can have.
+     */
+    return MIN(num_queues, VIRTIO_QUEUE_MAX - fixed_queues);
+}
+
 /* virtio-pci-bus */
 
 static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index e2eaaa9182..91096f0291 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -243,4 +243,13 @@ typedef struct VirtioPCIDeviceTypeInfo {
 /* Register virtio-pci type(s).  @t must be static. */
 void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t);
 
+/**
+ * virtio_pci_optimal_num_queues:
+ * @fixed_queues: number of queues that are always present
+ *
+ * Returns: The optimal number of queues for a multi-queue device, excluding
+ * @fixed_queues.
+ */
+unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues);
+
 #endif
diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
index c23a134202..fa4b3bfb50 100644
--- a/hw/virtio/virtio-scsi-pci.c
+++ b/hw/virtio/virtio-scsi-pci.c
@@ -46,12 +46,17 @@ static void virtio_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VirtIOSCSIPCI *dev = VIRTIO_SCSI_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
     DeviceState *proxy = DEVICE(vpci_dev);
+    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.conf;
     char *bus_name;
 
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
+
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues + 3;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     /*
diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
index 8bc4a4c01d..02f4665767 100644
--- a/include/hw/acpi/pcihp.h
+++ b/include/hw/acpi/pcihp.h
@@ -67,7 +67,7 @@ void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev,
                                          Error **errp);
 
 /* Called on reset */
-void acpi_pcihp_reset(AcpiPciHpState *s);
+void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off);
 
 extern const VMStateDescription vmstate_acpi_pcihp_pci_status;
 
diff --git a/include/hw/virtio/vhost-user-blk.h b/include/hw/virtio/vhost-user-blk.h
index 34ad6f0c0e..292d17147c 100644
--- a/include/hw/virtio/vhost-user-blk.h
+++ b/include/hw/virtio/vhost-user-blk.h
@@ -25,6 +25,8 @@
 #define VHOST_USER_BLK(obj) \
         OBJECT_CHECK(VHostUserBlk, (obj), TYPE_VHOST_USER_BLK)
 
+#define VHOST_USER_BLK_AUTO_NUM_QUEUES UINT16_MAX
+
 typedef struct VHostUserBlk {
     VirtIODevice parent_obj;
     CharBackend chardev;
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index b1334c3904..7539c2b848 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -30,6 +30,8 @@ struct virtio_blk_inhdr
     unsigned char status;
 };
 
+#define VIRTIO_BLK_AUTO_NUM_QUEUES UINT16_MAX
+
 struct VirtIOBlkConf
 {
     BlockConf conf;
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 24e768909d..c0b8e4dd7e 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -36,6 +36,11 @@
 #define VIRTIO_SCSI_MAX_TARGET  255
 #define VIRTIO_SCSI_MAX_LUN     16383
 
+/* Number of virtqueues that are always present */
+#define VIRTIO_SCSI_VQ_NUM_FIXED    2
+
+#define VIRTIO_SCSI_AUTO_NUM_QUEUES UINT32_MAX
+
 typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
 typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
 typedef struct virtio_scsi_ctrl_tmf_req VirtIOSCSICtrlTMFReq;
diff --git a/qemu-options.hx b/qemu-options.hx
index 708583b4ce..30019c4eca 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2294,7 +2294,7 @@ DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
     "              [,sku=str]\n"
     "                specify SMBIOS type 3 fields\n"
     "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
-    "              [,asset=str][,part=str]\n"
+    "              [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n"
     "                specify SMBIOS type 4 fields\n"
     "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
     "               [,asset=str][,part=str][,speed=%d]\n"
diff --git a/tests/data/acpi/disassemle-aml.sh b/tests/data/acpi/disassemle-aml.sh
index 1d8a4d0301..253b7620a0 100755
--- a/tests/data/acpi/disassemle-aml.sh
+++ b/tests/data/acpi/disassemle-aml.sh
@@ -42,11 +42,16 @@ do
         else
             extra=""
         fi
-        asl=${aml}.dsl
         if [[ "${outdir}" ]];
         then
-            asl="${outdir}"/${machine}/${asl}
+            # iasl strips an extension from prefix if there.
+            # since we have some files with . in the name, the
+            # last component gets interpreted as an extension:
+            # add another extension to work around that.
+            prefix="-p ${outdir}/${aml}.dsl"
+        else
+            prefix=""
         fi
-        iasl -d -p ${asl} ${extra} ${aml}
+        iasl ${extra} ${prefix} -d ${aml}
     done
 done
diff --git a/tests/data/acpi/pc/DSDT b/tests/data/acpi/pc/DSDT
index 6d0aaf729a..b121bb5bc1 100644
Binary files a/tests/data/acpi/pc/DSDT and b/tests/data/acpi/pc/DSDT differ
diff --git a/tests/data/acpi/pc/DSDT.acpihmat b/tests/data/acpi/pc/DSDT.acpihmat
index 2e5e02400b..b0dbb943f4 100644
Binary files a/tests/data/acpi/pc/DSDT.acpihmat and b/tests/data/acpi/pc/DSDT.acpihmat differ
diff --git a/tests/data/acpi/pc/DSDT.bridge b/tests/data/acpi/pc/DSDT.bridge
index 623c4c0358..7b6c7a4787 100644
Binary files a/tests/data/acpi/pc/DSDT.bridge and b/tests/data/acpi/pc/DSDT.bridge differ
diff --git a/tests/data/acpi/pc/DSDT.cphp b/tests/data/acpi/pc/DSDT.cphp
index e0a43ccdad..c0e8aa5b32 100644
Binary files a/tests/data/acpi/pc/DSDT.cphp and b/tests/data/acpi/pc/DSDT.cphp differ
diff --git a/tests/data/acpi/pc/DSDT.dimmpxm b/tests/data/acpi/pc/DSDT.dimmpxm
index 21eb065a0e..1649953b6c 100644
Binary files a/tests/data/acpi/pc/DSDT.dimmpxm and b/tests/data/acpi/pc/DSDT.dimmpxm differ
diff --git a/tests/data/acpi/pc/DSDT.ipmikcs b/tests/data/acpi/pc/DSDT.ipmikcs
index b8f08f266b..92748d49dc 100644
Binary files a/tests/data/acpi/pc/DSDT.ipmikcs and b/tests/data/acpi/pc/DSDT.ipmikcs differ
diff --git a/tests/data/acpi/pc/DSDT.memhp b/tests/data/acpi/pc/DSDT.memhp
index 9a9418f4bd..4026772906 100644
Binary files a/tests/data/acpi/pc/DSDT.memhp and b/tests/data/acpi/pc/DSDT.memhp differ
diff --git a/tests/data/acpi/pc/DSDT.numamem b/tests/data/acpi/pc/DSDT.numamem
index 6eec385c2e..4d9ba337a8 100644
Binary files a/tests/data/acpi/pc/DSDT.numamem and b/tests/data/acpi/pc/DSDT.numamem differ
diff --git a/tests/data/acpi/q35/DSDT b/tests/data/acpi/q35/DSDT
index e63676d7a6..bba8884073 100644
Binary files a/tests/data/acpi/q35/DSDT and b/tests/data/acpi/q35/DSDT differ
diff --git a/tests/data/acpi/q35/DSDT.acpihmat b/tests/data/acpi/q35/DSDT.acpihmat
index cd97b81982..9cac92418b 100644
Binary files a/tests/data/acpi/q35/DSDT.acpihmat and b/tests/data/acpi/q35/DSDT.acpihmat differ
diff --git a/tests/data/acpi/q35/DSDT.bridge b/tests/data/acpi/q35/DSDT.bridge
index 8b0fb497db..f08b7245f5 100644
Binary files a/tests/data/acpi/q35/DSDT.bridge and b/tests/data/acpi/q35/DSDT.bridge differ
diff --git a/tests/data/acpi/q35/DSDT.cphp b/tests/data/acpi/q35/DSDT.cphp
index d9bb414e9b..57d859cef9 100644
Binary files a/tests/data/acpi/q35/DSDT.cphp and b/tests/data/acpi/q35/DSDT.cphp differ
diff --git a/tests/data/acpi/q35/DSDT.dimmpxm b/tests/data/acpi/q35/DSDT.dimmpxm
index 29f19b22a3..9d5bd5744e 100644
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diff --git a/tests/data/acpi/q35/DSDT.ipmibt b/tests/data/acpi/q35/DSDT.ipmibt
index e8dea1ea42..5cd11de6a8 100644
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diff --git a/tests/data/acpi/q35/DSDT.memhp b/tests/data/acpi/q35/DSDT.memhp
index dca76db15b..05a7a73ec4 100644
Binary files a/tests/data/acpi/q35/DSDT.memhp and b/tests/data/acpi/q35/DSDT.memhp differ
diff --git a/tests/data/acpi/q35/DSDT.mmio64 b/tests/data/acpi/q35/DSDT.mmio64
index 6d8facd9e1..efd3f1188f 100644
Binary files a/tests/data/acpi/q35/DSDT.mmio64 and b/tests/data/acpi/q35/DSDT.mmio64 differ
diff --git a/tests/data/acpi/q35/DSDT.numamem b/tests/data/acpi/q35/DSDT.numamem
index 737325dc30..1978b55f12 100644
Binary files a/tests/data/acpi/q35/DSDT.numamem and b/tests/data/acpi/q35/DSDT.numamem differ
diff --git a/tests/data/acpi/q35/DSDT.tis b/tests/data/acpi/q35/DSDT.tis
index 27ee927fc5..638de38726 100644
Binary files a/tests/data/acpi/q35/DSDT.tis and b/tests/data/acpi/q35/DSDT.tis differ
diff --git a/tests/data/acpi/virt/DSDT b/tests/data/acpi/virt/DSDT
index e669508d17..9b002836f3 100644
Binary files a/tests/data/acpi/virt/DSDT and b/tests/data/acpi/virt/DSDT differ
diff --git a/tests/data/acpi/virt/DSDT.memhp b/tests/data/acpi/virt/DSDT.memhp
index 4cb81f692d..545a18c365 100644
Binary files a/tests/data/acpi/virt/DSDT.memhp and b/tests/data/acpi/virt/DSDT.memhp differ
diff --git a/tests/data/acpi/virt/DSDT.numamem b/tests/data/acpi/virt/DSDT.numamem
index e669508d17..9b002836f3 100644
Binary files a/tests/data/acpi/virt/DSDT.numamem and b/tests/data/acpi/virt/DSDT.numamem differ
diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
index d25ff35492..504b810af5 100644
--- a/tests/qtest/bios-tables-test.c
+++ b/tests/qtest/bios-tables-test.c
@@ -80,6 +80,8 @@ typedef struct {
     GArray *tables;
     uint32_t smbios_ep_addr;
     struct smbios_21_entry_point smbios_ep_table;
+    uint16_t smbios_cpu_max_speed;
+    uint16_t smbios_cpu_curr_speed;
     uint8_t *required_struct_types;
     int required_struct_types_len;
     QTestState *qts;
@@ -563,6 +565,31 @@ static inline bool smbios_single_instance(uint8_t type)
     }
 }
 
+static bool smbios_cpu_test(test_data *data, uint32_t addr)
+{
+    uint16_t expect_speed[2];
+    uint16_t real;
+    int offset[2];
+    int i;
+
+    /* Check CPU speed for backward compatibility */
+    offset[0] = offsetof(struct smbios_type_4, max_speed);
+    offset[1] = offsetof(struct smbios_type_4, current_speed);
+    expect_speed[0] = data->smbios_cpu_max_speed ? : 2000;
+    expect_speed[1] = data->smbios_cpu_curr_speed ? : 2000;
+
+    for (i = 0; i < 2; i++) {
+        real = qtest_readw(data->qts, addr + offset[i]);
+        if (real != expect_speed[i]) {
+            fprintf(stderr, "Unexpected SMBIOS CPU speed: real %u expect %u\n",
+                    real, expect_speed[i]);
+            return false;
+        }
+    }
+
+    return true;
+}
+
 static void test_smbios_structs(test_data *data)
 {
     DECLARE_BITMAP(struct_bitmap, SMBIOS_MAX_TYPE+1) = { 0 };
@@ -585,6 +612,10 @@ static void test_smbios_structs(test_data *data)
         }
         set_bit(type, struct_bitmap);
 
+        if (type == 4) {
+            g_assert(smbios_cpu_test(data, addr));
+        }
+
         /* seek to end of unformatted string area of this struct ("\0\0") */
         prv = crt = 1;
         while (prv || crt) {
@@ -719,6 +750,11 @@ static void test_acpi_q35_tcg(void)
     data.required_struct_types_len = ARRAY_SIZE(base_required_struct_types);
     test_acpi_one(NULL, &data);
     free_test_data(&data);
+
+    data.smbios_cpu_max_speed = 3000;
+    data.smbios_cpu_curr_speed = 2600;
+    test_acpi_one("-smbios type=4,max-speed=3000,current-speed=2600", &data);
+    free_test_data(&data);
 }
 
 static void test_acpi_q35_tcg_bridge(void)
@@ -1084,6 +1120,12 @@ static void test_acpi_virt_tcg(void)
 
     test_acpi_one("-cpu cortex-a57", &data);
     free_test_data(&data);
+
+    data.smbios_cpu_max_speed = 2900;
+    data.smbios_cpu_curr_speed = 2700;
+    test_acpi_one("-cpu cortex-a57 "
+                  "-smbios type=4,max-speed=2900,current-speed=2700", &data);
+    free_test_data(&data);
 }
 
 int main(int argc, char *argv[])