From 751b4b7b4b7b5bd1e399e3756ef62cc1ef03b177 Mon Sep 17 00:00:00 2001 From: Damien Hedde Date: Thu, 30 Jan 2020 16:02:05 +0000 Subject: [PATCH] vl: replace deprecated qbus_reset_all registration MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Replace deprecated qbus_reset_all by resettable_cold_reset_fn for the sysbus reset registration. Apart for the raspi machines, this does not impact the behavior because: + at this point resettable just calls the old reset methods of devices and buses in the same order as qdev/qbus. + resettable handlers registered with qemu_register_reset are serialized; there is no interleaving. + eventual explicit calls to legacy reset API (device_reset or qdev/qbus_reset) inside this reset handler will not be masked out by resettable mechanism; they do not go through resettable api. For the raspi machines, during the sysbus reset the sd-card is not reset twice anymore but only once. This is a consequence of switching both sysbus reset and changing parent to resettable; it detects the second reset is not needed. This has no impact on the state after reset; the sd-card reset method only reset local state and query information from the block backend. The raspi reset change can be observed by using the following command (reset will occurs, then do Ctrl-C to end qemu; no firmware is given here). qemu-system-aarch64 -M raspi3 \ -trace resettable_phase_hold_exec \ -trace qdev_update_parent_bus \ -trace resettable_change_parent \ -trace qdev_reset -trace qbus_reset Before the patch, the qdev/qbus_reset traces show when reset method are called. After the patch, the resettable_phase_hold_exec show when reset method are called. The traced reset order of the raspi3 is listed below. I've added empty lines and the tree structure. +->bcm2835-peripherals reset | | +->sd-card reset | +->sd-bus reset +->bcm2835_gpio reset | -> dev_update_parent_bus (move the sd-card on the sdhci-bus) | -> resettable_change_parent | +->bcm2835-dma reset | | +->bcm2835-sdhost-bus reset +->bcm2835-sdhost reset | | +->sd-card (reset ONLY BEFORE BEFORE THE PATCH) | +->sdhci-bus reset +->generic-sdhci reset | +->bcm2835-rng reset +->bcm2835-property reset +->bcm2835-fb reset +->bcm2835-mbox reset +->bcm2835-aux reset +->pl011 reset +->bcm2835-ic reset +->bcm2836-control reset System reset In both case, the sd-card is reset (being on bcm2835_gpio/sd-bus) then moved to generic-sdhci/sdhci-bus by the bcm2835_gpio reset method. Before the patch, it is then reset again being part of generic-sdhci/sdhci-bus. After the patch, it considered again for reset but its reset method is not called because it is already flagged as reset. Signed-off-by: Damien Hedde Reviewed-by: Peter Maydell Reviewed-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé Tested-by: Philippe Mathieu-Daudé Message-id: 20200123132823.1117486-11-damien.hedde@greensocs.com Signed-off-by: Peter Maydell --- vl.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/vl.c b/vl.c index b0f52c4d6e..24951b51a9 100644 --- a/vl.c +++ b/vl.c @@ -4381,7 +4381,15 @@ int main(int argc, char **argv, char **envp) /* TODO: once all bus devices are qdevified, this should be done * when bus is created by qdev.c */ - qemu_register_reset(qbus_reset_all_fn, sysbus_get_default()); + /* + * TODO: If we had a main 'reset container' that the whole system + * lived in, we could reset that using the multi-phase reset + * APIs. For the moment, we just reset the sysbus, which will cause + * all devices hanging off it (and all their child buses, recursively) + * to be reset. Note that this will *not* reset any Device objects + * which are not attached to some part of the qbus tree! + */ + qemu_register_reset(resettable_cold_reset_fn, sysbus_get_default()); qemu_run_machine_init_done_notifiers(); if (rom_check_and_register_reset() != 0) {