hw/virtio-pci: fix virtio behaviour

Enable transitional virtio devices by default.
Enable virtio-1.0 for devices plugged into
PCIe ports (Root ports or Downstream ports).

Using the virtio-1 mode will remove the limitation
of the number of devices that can be attached to a machine
by removing the need for the IO BAR.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

5 files changed, 45 insertions, 26 deletions

diff --git a/hw/display/virtio-gpu-pci.c b/hw/display/virtio-gpu-pci.c
index a71b230d33..34a724c754 100644
--- a/hw/display/virtio-gpu-pci.c
+++ b/hw/display/virtio-gpu-pci.c
@@ -30,9 +30,7 @@ static void virtio_gpu_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     int i;
 
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
-    /* force virtio-1.0 */
-    vpci_dev->flags &= ~VIRTIO_PCI_FLAG_DISABLE_MODERN;
-    vpci_dev->flags |= VIRTIO_PCI_FLAG_DISABLE_LEGACY;
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);
 
     for (i = 0; i < g->conf.max_outputs; i++) {
diff --git a/hw/display/virtio-vga.c b/hw/display/virtio-vga.c
index 315b7fc58c..5b510a17fd 100644
--- a/hw/display/virtio-vga.c
+++ b/hw/display/virtio-vga.c
@@ -134,9 +134,7 @@ static void virtio_vga_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 
     /* init virtio bits */
     qdev_set_parent_bus(DEVICE(g), BUS(&vpci_dev->bus));
-    /* force virtio-1.0 */
-    vpci_dev->flags &= ~VIRTIO_PCI_FLAG_DISABLE_MODERN;
-    vpci_dev->flags |= VIRTIO_PCI_FLAG_DISABLE_LEGACY;
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(g), true, "realized", &err);
     if (err) {
         error_propagate(errp, err);
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index f0677b73d8..755f9218b7 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -161,7 +161,7 @@ static bool virtio_pci_modern_state_needed(void *opaque)
 {
     VirtIOPCIProxy *proxy = opaque;
 
-    return !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
+    return virtio_pci_modern(proxy);
 }
 
 static const VMStateDescription vmstate_virtio_pci_modern_state = {
@@ -300,8 +300,8 @@ static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier *notifier,
     VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
     VirtQueue *vq = virtio_get_queue(vdev, n);
-    bool legacy = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_LEGACY);
-    bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
+    bool legacy = virtio_pci_legacy(proxy);
+    bool modern = virtio_pci_modern(proxy);
     bool fast_mmio = kvm_ioeventfd_any_length_enabled();
     bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
     MemoryRegion *modern_mr = &proxy->notify.mr;
@@ -1574,8 +1574,8 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
 {
     VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
     VirtioBusState *bus = &proxy->bus;
-    bool legacy = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_LEGACY);
-    bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
+    bool legacy = virtio_pci_legacy(proxy);
+    bool modern = virtio_pci_modern(proxy);
     bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
     uint8_t *config;
     uint32_t size;
@@ -1694,7 +1694,7 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
 static void virtio_pci_device_unplugged(DeviceState *d)
 {
     VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
-    bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
+    bool modern = virtio_pci_modern(proxy);
     bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
 
     virtio_pci_stop_ioeventfd(proxy);
@@ -1714,6 +1714,8 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
 {
     VirtIOPCIProxy *proxy = VIRTIO_PCI(pci_dev);
     VirtioPCIClass *k = VIRTIO_PCI_GET_CLASS(pci_dev);
+    bool pcie_port = pci_bus_is_express(pci_dev->bus) &&
+                     !pci_bus_is_root(pci_dev->bus);
 
     /*
      * virtio pci bar layout used by default.
@@ -1764,8 +1766,11 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
 
     address_space_init(&proxy->modern_as, &proxy->modern_cfg, "virtio-pci-cfg-as");
 
-    if (pci_is_express(pci_dev) && pci_bus_is_express(pci_dev->bus) &&
-        !pci_bus_is_root(pci_dev->bus)) {
+    if (proxy->disable_legacy == ON_OFF_AUTO_AUTO) {
+        proxy->disable_legacy = pcie_port ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+    }
+
+    if (pcie_port && pci_is_express(pci_dev)) {
         int pos;
 
         pos = pcie_endpoint_cap_init(pci_dev, 0);
@@ -1819,10 +1824,9 @@ static void virtio_pci_reset(DeviceState *qdev)
 static Property virtio_pci_properties[] = {
     DEFINE_PROP_BIT("virtio-pci-bus-master-bug-migration", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_BUS_MASTER_BUG_MIGRATION_BIT, false),
-    DEFINE_PROP_BIT("disable-legacy", VirtIOPCIProxy, flags,
-                    VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT, false),
-    DEFINE_PROP_BIT("disable-modern", VirtIOPCIProxy, flags,
-                    VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT, true),
+    DEFINE_PROP_ON_OFF_AUTO("disable-legacy", VirtIOPCIProxy, disable_legacy,
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_BOOL("disable-modern", VirtIOPCIProxy, disable_modern, false),
     DEFINE_PROP_BIT("migrate-extra", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_MIGRATE_EXTRA_BIT, true),
     DEFINE_PROP_BIT("modern-pio-notify", VirtIOPCIProxy, flags,
@@ -1839,7 +1843,7 @@ static void virtio_pci_dc_realize(DeviceState *qdev, Error **errp)
     PCIDevice *pci_dev = &proxy->pci_dev;
 
     if (!(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_PCIE) &&
-        !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN)) {
+        virtio_pci_modern(proxy)) {
         pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
     }
 
@@ -2301,9 +2305,7 @@ static void virtio_input_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     DeviceState *vdev = DEVICE(&vinput->vdev);
 
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
-    /* force virtio-1.0 */
-    vpci_dev->flags &= ~VIRTIO_PCI_FLAG_DISABLE_MODERN;
-    vpci_dev->flags |= VIRTIO_PCI_FLAG_DISABLE_LEGACY;
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);
 }
 
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index e4548c2f97..25fbf8a375 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -61,8 +61,6 @@ typedef struct VirtioBusClass VirtioPCIBusClass;
 enum {
     VIRTIO_PCI_FLAG_BUS_MASTER_BUG_MIGRATION_BIT,
     VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT,
-    VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT,
-    VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT,
     VIRTIO_PCI_FLAG_MIGRATE_EXTRA_BIT,
     VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT,
     VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT,
@@ -77,8 +75,6 @@ enum {
 #define VIRTIO_PCI_FLAG_USE_IOEVENTFD   (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT)
 
 /* virtio version flags */
-#define VIRTIO_PCI_FLAG_DISABLE_LEGACY (1 << VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT)
-#define VIRTIO_PCI_FLAG_DISABLE_MODERN (1 << VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT)
 #define VIRTIO_PCI_FLAG_DISABLE_PCIE (1 << VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT)
 
 /* migrate extra state */
@@ -144,6 +140,8 @@ struct VirtIOPCIProxy {
     uint32_t modern_mem_bar;
     int config_cap;
     uint32_t flags;
+    bool disable_modern;
+    OnOffAuto disable_legacy;
     uint32_t class_code;
     uint32_t nvectors;
     uint32_t dfselect;
@@ -158,6 +156,21 @@ struct VirtIOPCIProxy {
     VirtioBusState bus;
 };
 
+static inline bool virtio_pci_modern(VirtIOPCIProxy *proxy)
+{
+    return !proxy->disable_modern;
+}
+
+static inline bool virtio_pci_legacy(VirtIOPCIProxy *proxy)
+{
+    return proxy->disable_legacy == ON_OFF_AUTO_OFF;
+}
+
+static inline void virtio_pci_force_virtio_1(VirtIOPCIProxy *proxy)
+{
+    proxy->disable_modern = false;
+    proxy->disable_legacy = ON_OFF_AUTO_ON;
+}
 
 /*
  * virtio-scsi-pci: This extends VirtioPCIProxy.
diff --git a/include/hw/compat.h b/include/hw/compat.h
index e5113dcabc..7ee7299c36 100644
--- a/include/hw/compat.h
+++ b/include/hw/compat.h
@@ -6,6 +6,14 @@
         .driver   = "virtio-mmio",\
         .property = "format_transport_address",\
         .value    = "off",\
+    },{\
+        .driver   = "virtio-pci",\
+        .property = "disable-modern",\
+        .value    = "on",\
+    },{\
+        .driver   = "virtio-pci",\
+        .property = "disable-legacy",\
+        .value    = "off",\
     },
 
 #define HW_COMPAT_2_5 \