qemu/hw/display/virtio-gpu-base.c
Markus Armbruster b69c3c21a5 qdev: Unrealize must not fail
Devices may have component devices and buses.

Device realization may fail.  Realization is recursive: a device's
realize() method realizes its components, and device_set_realized()
realizes its buses (which should in turn realize the devices on that
bus, except bus_set_realized() doesn't implement that, yet).

When realization of a component or bus fails, we need to roll back:
unrealize everything we realized so far.  If any of these unrealizes
failed, the device would be left in an inconsistent state.  Must not
happen.

device_set_realized() lets it happen: it ignores errors in the roll
back code starting at label child_realize_fail.

Since realization is recursive, unrealization must be recursive, too.
But how could a partly failed unrealize be rolled back?  We'd have to
re-realize, which can fail.  This design is fundamentally broken.

device_set_realized() does not roll back at all.  Instead, it keeps
unrealizing, ignoring further errors.

It can screw up even for a device with no buses: if the lone
dc->unrealize() fails, it still unregisters vmstate, and calls
listeners' unrealize() callback.

bus_set_realized() does not roll back either.  Instead, it stops
unrealizing.

Fortunately, no unrealize method can fail, as we'll see below.

To fix the design error, drop parameter @errp from all the unrealize
methods.

Any unrealize method that uses @errp now needs an update.  This leads
us to unrealize() methods that can fail.  Merely passing it to another
unrealize method cannot cause failure, though.  Here are the ones that
do other things with @errp:

* virtio_serial_device_unrealize()

  Fails when qbus_set_hotplug_handler() fails, but still does all the
  other work.  On failure, the device would stay realized with its
  resources completely gone.  Oops.  Can't happen, because
  qbus_set_hotplug_handler() can't actually fail here.  Pass
  &error_abort to qbus_set_hotplug_handler() instead.

* hw/ppc/spapr_drc.c's unrealize()

  Fails when object_property_del() fails, but all the other work is
  already done.  On failure, the device would stay realized with its
  vmstate registration gone.  Oops.  Can't happen, because
  object_property_del() can't actually fail here.  Pass &error_abort
  to object_property_del() instead.

* spapr_phb_unrealize()

  Fails and bails out when remove_drcs() fails, but other work is
  already done.  On failure, the device would stay realized with some
  of its resources gone.  Oops.  remove_drcs() fails only when
  chassis_from_bus()'s object_property_get_uint() fails, and it can't
  here.  Pass &error_abort to remove_drcs() instead.

Therefore, no unrealize method can fail before this patch.

device_set_realized()'s recursive unrealization via bus uses
object_property_set_bool().  Can't drop @errp there, so pass
&error_abort.

We similarly unrealize with object_property_set_bool() elsewhere,
always ignoring errors.  Pass &error_abort instead.

Several unrealize methods no longer handle errors from other unrealize
methods: virtio_9p_device_unrealize(),
virtio_input_device_unrealize(), scsi_qdev_unrealize(), ...
Much of the deleted error handling looks wrong anyway.

One unrealize methods no longer ignore such errors:
usb_ehci_pci_exit().

Several realize methods no longer ignore errors when rolling back:
v9fs_device_realize_common(), pci_qdev_unrealize(),
spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(),
virtio_device_realize().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-17-armbru@redhat.com>
2020-05-15 07:08:14 +02:00

269 lines
7.8 KiB
C

/*
* Virtio GPU Device
*
* Copyright Red Hat, Inc. 2013-2014
*
* Authors:
* Dave Airlie <airlied@redhat.com>
* Gerd Hoffmann <kraxel@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "hw/virtio/virtio-gpu.h"
#include "migration/blocker.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "trace.h"
void
virtio_gpu_base_reset(VirtIOGPUBase *g)
{
int i;
g->enable = 0;
g->use_virgl_renderer = false;
for (i = 0; i < g->conf.max_outputs; i++) {
g->scanout[i].resource_id = 0;
g->scanout[i].width = 0;
g->scanout[i].height = 0;
g->scanout[i].x = 0;
g->scanout[i].y = 0;
g->scanout[i].ds = NULL;
}
}
void
virtio_gpu_base_fill_display_info(VirtIOGPUBase *g,
struct virtio_gpu_resp_display_info *dpy_info)
{
int i;
for (i = 0; i < g->conf.max_outputs; i++) {
if (g->enabled_output_bitmask & (1 << i)) {
dpy_info->pmodes[i].enabled = 1;
dpy_info->pmodes[i].r.width = cpu_to_le32(g->req_state[i].width);
dpy_info->pmodes[i].r.height = cpu_to_le32(g->req_state[i].height);
}
}
}
static void virtio_gpu_invalidate_display(void *opaque)
{
}
static void virtio_gpu_update_display(void *opaque)
{
}
static void virtio_gpu_text_update(void *opaque, console_ch_t *chardata)
{
}
static void virtio_gpu_notify_event(VirtIOGPUBase *g, uint32_t event_type)
{
g->virtio_config.events_read |= event_type;
virtio_notify_config(&g->parent_obj);
}
static int virtio_gpu_ui_info(void *opaque, uint32_t idx, QemuUIInfo *info)
{
VirtIOGPUBase *g = opaque;
if (idx >= g->conf.max_outputs) {
return -1;
}
g->req_state[idx].x = info->xoff;
g->req_state[idx].y = info->yoff;
g->req_state[idx].width = info->width;
g->req_state[idx].height = info->height;
if (info->width && info->height) {
g->enabled_output_bitmask |= (1 << idx);
} else {
g->enabled_output_bitmask &= ~(1 << idx);
}
/* send event to guest */
virtio_gpu_notify_event(g, VIRTIO_GPU_EVENT_DISPLAY);
return 0;
}
static void
virtio_gpu_gl_block(void *opaque, bool block)
{
VirtIOGPUBase *g = opaque;
VirtIOGPUBaseClass *vgc = VIRTIO_GPU_BASE_GET_CLASS(g);
if (block) {
g->renderer_blocked++;
} else {
g->renderer_blocked--;
}
assert(g->renderer_blocked >= 0);
if (g->renderer_blocked == 0) {
vgc->gl_unblock(g);
}
}
const GraphicHwOps virtio_gpu_ops = {
.invalidate = virtio_gpu_invalidate_display,
.gfx_update = virtio_gpu_update_display,
.text_update = virtio_gpu_text_update,
.ui_info = virtio_gpu_ui_info,
.gl_block = virtio_gpu_gl_block,
};
bool
virtio_gpu_base_device_realize(DeviceState *qdev,
VirtIOHandleOutput ctrl_cb,
VirtIOHandleOutput cursor_cb,
Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
VirtIOGPUBase *g = VIRTIO_GPU_BASE(qdev);
Error *local_err = NULL;
int i;
if (g->conf.max_outputs > VIRTIO_GPU_MAX_SCANOUTS) {
error_setg(errp, "invalid max_outputs > %d", VIRTIO_GPU_MAX_SCANOUTS);
return false;
}
g->use_virgl_renderer = false;
if (virtio_gpu_virgl_enabled(g->conf)) {
error_setg(&g->migration_blocker, "virgl is not yet migratable");
migrate_add_blocker(g->migration_blocker, &local_err);
if (local_err) {
error_propagate(errp, local_err);
error_free(g->migration_blocker);
return false;
}
}
g->virtio_config.num_scanouts = cpu_to_le32(g->conf.max_outputs);
virtio_init(VIRTIO_DEVICE(g), "virtio-gpu", VIRTIO_ID_GPU,
sizeof(struct virtio_gpu_config));
if (virtio_gpu_virgl_enabled(g->conf)) {
/* use larger control queue in 3d mode */
virtio_add_queue(vdev, 256, ctrl_cb);
virtio_add_queue(vdev, 16, cursor_cb);
} else {
virtio_add_queue(vdev, 64, ctrl_cb);
virtio_add_queue(vdev, 16, cursor_cb);
}
g->enabled_output_bitmask = 1;
g->req_state[0].width = g->conf.xres;
g->req_state[0].height = g->conf.yres;
for (i = 0; i < g->conf.max_outputs; i++) {
g->scanout[i].con =
graphic_console_init(DEVICE(g), i, &virtio_gpu_ops, g);
if (i > 0) {
dpy_gfx_replace_surface(g->scanout[i].con, NULL);
}
}
return true;
}
static uint64_t
virtio_gpu_base_get_features(VirtIODevice *vdev, uint64_t features,
Error **errp)
{
VirtIOGPUBase *g = VIRTIO_GPU_BASE(vdev);
if (virtio_gpu_virgl_enabled(g->conf)) {
features |= (1 << VIRTIO_GPU_F_VIRGL);
}
if (virtio_gpu_edid_enabled(g->conf)) {
features |= (1 << VIRTIO_GPU_F_EDID);
}
return features;
}
static void
virtio_gpu_base_set_features(VirtIODevice *vdev, uint64_t features)
{
static const uint32_t virgl = (1 << VIRTIO_GPU_F_VIRGL);
VirtIOGPUBase *g = VIRTIO_GPU_BASE(vdev);
g->use_virgl_renderer = ((features & virgl) == virgl);
trace_virtio_gpu_features(g->use_virgl_renderer);
}
static void
virtio_gpu_base_device_unrealize(DeviceState *qdev)
{
VirtIOGPUBase *g = VIRTIO_GPU_BASE(qdev);
if (g->migration_blocker) {
migrate_del_blocker(g->migration_blocker);
error_free(g->migration_blocker);
}
}
static void
virtio_gpu_base_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
vdc->unrealize = virtio_gpu_base_device_unrealize;
vdc->get_features = virtio_gpu_base_get_features;
vdc->set_features = virtio_gpu_base_set_features;
set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
dc->hotpluggable = false;
}
static const TypeInfo virtio_gpu_base_info = {
.name = TYPE_VIRTIO_GPU_BASE,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VirtIOGPUBase),
.class_size = sizeof(VirtIOGPUBaseClass),
.class_init = virtio_gpu_base_class_init,
.abstract = true
};
static void
virtio_register_types(void)
{
type_register_static(&virtio_gpu_base_info);
}
type_init(virtio_register_types)
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_ctrl_hdr) != 24);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_update_cursor) != 56);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resource_unref) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resource_create_2d) != 40);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_set_scanout) != 48);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resource_flush) != 48);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_transfer_to_host_2d) != 56);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_mem_entry) != 16);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resource_attach_backing) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resource_detach_backing) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resp_display_info) != 408);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_transfer_host_3d) != 72);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resource_create_3d) != 72);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_ctx_create) != 96);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_ctx_destroy) != 24);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_ctx_resource) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_cmd_submit) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_get_capset_info) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resp_capset_info) != 40);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_get_capset) != 32);
QEMU_BUILD_BUG_ON(sizeof(struct virtio_gpu_resp_capset) != 24);