| Message ID | 20110104193743.1909.65407.stgit@s20.home |
|---|---|
| State | New |
| Headers | show |
Alex Williamson <alex.williamson@redhat.com> writes: > Create a trivial interface to track whether the machine has been > modified since boot. Adding or removing devices will trigger this > to return true. An example usage scenario for such an interface is > the rtl8139 driver which includes a cpu_register_io_memory() value > in it's migration stream. For the majority of migrations, where > no hotplug has occured in the machine, this works correctly. Once > the machine is modified, we can use this interface to detect that > and include a subsection for the device to prevent migrations to > rtl8139 versions with this bug. > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > Acked-by: Michael S. Tsirkin <mst@redhat.com> > Acked-by: Juan Quintela <quintela@redhat.com> > --- > > hw/qdev.c | 10 ++++++++++ > hw/qdev.h | 1 + > 2 files changed, 11 insertions(+), 0 deletions(-) > > diff --git a/hw/qdev.c b/hw/qdev.c > index 6fc9b02..e450c21 100644 > --- a/hw/qdev.c > +++ b/hw/qdev.c > @@ -32,6 +32,8 @@ > #include "blockdev.h" > > static int qdev_hotplug = 0; > +static bool qdev_hot_added = false; > +static bool qdev_hot_removed = false; > > /* This is a nasty hack to allow passing a NULL bus to qdev_create. */ > static BusState *main_system_bus; > @@ -93,6 +95,7 @@ static DeviceState *qdev_create_from_info(BusState *bus, DeviceInfo *info) > if (qdev_hotplug) { > assert(bus->allow_hotplug); > dev->hotplugged = 1; > + qdev_hot_added = true; > } > dev->instance_id_alias = -1; > dev->state = DEV_STATE_CREATED; > @@ -294,6 +297,8 @@ int qdev_unplug(DeviceState *dev) > } > assert(dev->info->unplug != NULL); > > + qdev_hot_removed = true; > + > return dev->info->unplug(dev); > } > > @@ -394,6 +399,11 @@ void qdev_machine_creation_done(void) > qdev_hotplug = 1; > } > > +bool qdev_machine_modified(void) > +{ > + return qdev_hot_added || qdev_hot_removed; > +} > + > /* Get a character (serial) device interface. */ > CharDriverState *qdev_init_chardev(DeviceState *dev) > { Why do you track add/remove separately, in qdev_hot_added and qdev_hot_removed? I don't mind, just curious. [...]
On Wed, 2011-01-12 at 13:09 +0100, Markus Armbruster wrote: > Alex Williamson <alex.williamson@redhat.com> writes: > > > Create a trivial interface to track whether the machine has been > > modified since boot. Adding or removing devices will trigger this > > to return true. An example usage scenario for such an interface is > > the rtl8139 driver which includes a cpu_register_io_memory() value > > in it's migration stream. For the majority of migrations, where > > no hotplug has occured in the machine, this works correctly. Once > > the machine is modified, we can use this interface to detect that > > and include a subsection for the device to prevent migrations to > > rtl8139 versions with this bug. > > > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > > Acked-by: Michael S. Tsirkin <mst@redhat.com> > > Acked-by: Juan Quintela <quintela@redhat.com> > > --- > > > > hw/qdev.c | 10 ++++++++++ > > hw/qdev.h | 1 + > > 2 files changed, 11 insertions(+), 0 deletions(-) > > > > diff --git a/hw/qdev.c b/hw/qdev.c > > index 6fc9b02..e450c21 100644 > > --- a/hw/qdev.c > > +++ b/hw/qdev.c > > @@ -32,6 +32,8 @@ > > #include "blockdev.h" > > > > static int qdev_hotplug = 0; > > +static bool qdev_hot_added = false; > > +static bool qdev_hot_removed = false; > > > > /* This is a nasty hack to allow passing a NULL bus to qdev_create. */ > > static BusState *main_system_bus; > > @@ -93,6 +95,7 @@ static DeviceState *qdev_create_from_info(BusState *bus, DeviceInfo *info) > > if (qdev_hotplug) { > > assert(bus->allow_hotplug); > > dev->hotplugged = 1; > > + qdev_hot_added = true; > > } > > dev->instance_id_alias = -1; > > dev->state = DEV_STATE_CREATED; > > @@ -294,6 +297,8 @@ int qdev_unplug(DeviceState *dev) > > } > > assert(dev->info->unplug != NULL); > > > > + qdev_hot_removed = true; > > + > > return dev->info->unplug(dev); > > } > > > > @@ -394,6 +399,11 @@ void qdev_machine_creation_done(void) > > qdev_hotplug = 1; > > } > > > > +bool qdev_machine_modified(void) > > +{ > > + return qdev_hot_added || qdev_hot_removed; > > +} > > + > > /* Get a character (serial) device interface. */ > > CharDriverState *qdev_init_chardev(DeviceState *dev) > > { > > Why do you track add/remove separately, in qdev_hot_added and > qdev_hot_removed? I don't mind, just curious. I thought the distinction might be useful at some point, but we don't use it yet. Thanks, Alex
diff --git a/hw/qdev.c b/hw/qdev.c index 6fc9b02..e450c21 100644 --- a/hw/qdev.c +++ b/hw/qdev.c @@ -32,6 +32,8 @@ #include "blockdev.h" static int qdev_hotplug = 0; +static bool qdev_hot_added = false; +static bool qdev_hot_removed = false; /* This is a nasty hack to allow passing a NULL bus to qdev_create. */ static BusState *main_system_bus; @@ -93,6 +95,7 @@ static DeviceState *qdev_create_from_info(BusState *bus, DeviceInfo *info) if (qdev_hotplug) { assert(bus->allow_hotplug); dev->hotplugged = 1; + qdev_hot_added = true; } dev->instance_id_alias = -1; dev->state = DEV_STATE_CREATED; @@ -294,6 +297,8 @@ int qdev_unplug(DeviceState *dev) } assert(dev->info->unplug != NULL); + qdev_hot_removed = true; + return dev->info->unplug(dev); } @@ -394,6 +399,11 @@ void qdev_machine_creation_done(void) qdev_hotplug = 1; } +bool qdev_machine_modified(void) +{ + return qdev_hot_added || qdev_hot_removed; +} + /* Get a character (serial) device interface. */ CharDriverState *qdev_init_chardev(DeviceState *dev) { diff --git a/hw/qdev.h b/hw/qdev.h index aaaf55a..273bbac 100644 --- a/hw/qdev.h +++ b/hw/qdev.h @@ -132,6 +132,7 @@ int qdev_unplug(DeviceState *dev); void qdev_free(DeviceState *dev); int qdev_simple_unplug_cb(DeviceState *dev); void qdev_machine_creation_done(void); +bool qdev_machine_modified(void); qemu_irq qdev_get_gpio_in(DeviceState *dev, int n); void qdev_connect_gpio_out(DeviceState *dev, int n, qemu_irq pin);