virtio, pc: fixes

virtio and misc fixes for 2.9.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging

virtio, pc: fixes

virtio and misc fixes for 2.9.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Wed 22 Mar 2017 16:29:50 GMT
# gpg:                using RSA key 0x281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17  0970 C350 3912 AFBE 8E67
#      Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA  8A0D 281F 0DB8 D28D 5469

* remotes/mst/tags/for_upstream:
  hw/acpi/vmgenid: prevent more than one vmgenid device
  hw/acpi/vmgenid: prevent device realization on pre-2.5 machine types
  virtio: always use handle_aio_output if registered
  virtio: Fix error handling in virtio_bus_device_plugged

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/acpi/vmgenid.c

@@ -205,9 +205,30 @@ static void vmgenid_handle_reset(void *opaque)
     memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le));
 }
 
+static Property vmgenid_properties[] = {
+    DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState,
+                     write_pointer_available, true),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void vmgenid_realize(DeviceState *dev, Error **errp)
 {
     VmGenIdState *vms = VMGENID(dev);
+
+    if (!vms->write_pointer_available) {
+        error_setg(errp, "%s requires DMA write support in fw_cfg, "
+                   "which this machine type does not provide", VMGENID_DEVICE);
+        return;
+    }
+
+    /* Given that this function is executing, there is at least one VMGENID
+     * device. Check if there are several.
+     */
+    if (!find_vmgenid_dev()) {
+        error_setg(errp, "at most one %s device is permitted", VMGENID_DEVICE);
+        return;
+    }
+
     qemu_register_reset(vmgenid_handle_reset, vms);
 }
 
@@ -218,6 +239,7 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data)
     dc->vmsd = &vmstate_vmgenid;
     dc->realize = vmgenid_realize;
     dc->hotpluggable = false;
+    dc->props = vmgenid_properties;
 
     object_class_property_add_str(klass, VMGENID_GUID, NULL,
                                   vmgenid_set_guid, NULL);

hw/virtio/virtio-bus.c

@@ -25,6 +25,7 @@
 #include "qemu/osdep.h"
 #include "hw/hw.h"
 #include "qemu/error-report.h"
+#include "qapi/error.h"
 #include "hw/qdev.h"
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio.h"
@@ -48,20 +49,33 @@ void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
     bool has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
+    Error *local_err = NULL;
 
     DPRINTF("%s: plug device.\n", qbus->name);
 
     if (klass->pre_plugged != NULL) {
-        klass->pre_plugged(qbus->parent, errp);
+        klass->pre_plugged(qbus->parent, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
     }
 
     /* Get the features of the plugged device. */
     assert(vdc->get_features != NULL);
     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
-                                            errp);
+                                            &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
 
     if (klass->device_plugged != NULL) {
-        klass->device_plugged(qbus->parent, errp);
+        klass->device_plugged(qbus->parent, &local_err);
+    }
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
     }
 
     if (klass->get_dma_as != NULL && has_iommu) {

hw/virtio/virtio.c

@@ -1528,7 +1528,18 @@ static void virtio_queue_notify_vq(VirtQueue *vq)
 
 void virtio_queue_notify(VirtIODevice *vdev, int n)
 {
-    virtio_queue_notify_vq(&vdev->vq[n]);
+    VirtQueue *vq = &vdev->vq[n];
+
+    if (unlikely(!vq->vring.desc || vdev->broken)) {
+        return;
+    }
+
+    trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
+    if (vq->handle_aio_output) {
+        event_notifier_set(&vq->host_notifier);
+    } else if (vq->handle_output) {
+        vq->handle_output(vdev, vq);
+    }
 }
 
 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)

include/hw/acpi/vmgenid.h

@@ -21,8 +21,10 @@ typedef struct VmGenIdState {
     DeviceClass parent_obj;
     QemuUUID guid;                /* The 128-bit GUID seen by the guest */
     uint8_t vmgenid_addr_le[8];   /* Address of the GUID (little-endian) */
+    bool write_pointer_available;
 } VmGenIdState;
 
+/* returns NULL unless there is exactly one device */
 static inline Object *find_vmgenid_dev(void)
 {
     return object_resolve_path_type("", VMGENID_DEVICE, NULL);

include/hw/compat.h

@@ -131,6 +131,10 @@
         .driver   = "fw_cfg_io",\
         .property = "dma_enabled",\
         .value    = "off",\
+    },{\
+        .driver   = "vmgenid",\
+        .property = "x-write-pointer-available",\
+        .value    = "off",\
     },
 
 #define HW_COMPAT_2_3 \