Re: [PATCH v2 03/24] sd/pxa2xx_mmci: Fix to realize "pxa2xx-mmci" device - Philippe Mathieu-Daudé

From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	berrange@redhat.com, ehabkost@redhat.com, qemu-arm@nongnu.org,
	pbonzini@redhat.com
Subject: Re: [PATCH v2 03/24] sd/pxa2xx_mmci: Fix to realize "pxa2xx-mmci" device
Date: Mon, 8 Jun 2020 16:04:48 +0200	[thread overview]
Message-ID: <8cff82e9-b5ad-ab4d-d164-5ffe91337b1b@amsat.org> (raw)
In-Reply-To: <20200528110444.20456-4-armbru@redhat.com>

On 5/28/20 1:04 PM, Markus Armbruster wrote:
> pxa2xx_mmci_init() creates a "pxa2xx-mmci" device, but neglects to
> realize it.  Affects machines akita, borzoi, connex, mainstone, spitz,
> terrier, tosa, verdex, and z2.
> 
> In theory, a device becomes real only on realize.  In practice, the
> transition from unreal to real is a fuzzy one.  The work to make a
> device real can be spread between realize methods (fine),
> instance_init methods (wrong), and board code wiring up the device
> (fine as long as it effectively happens on realize).  Depending on
> what exactly is done where, a device can work even when we neglect
> to realize it.
> 
> This one appears to work.  Nevertheless, it's a clear misuse of the
> interface.  Even when it works today (more or less by chance), it can
> break tomorrow.
> 
> Fix by realizing it right away.  Visible in "info qom-tree"; here's
> the change for akita:
> 
>      /machine (akita-machine)
>        [...]
>        /unattached (container)
>          [...]
>     +    /device[5] (pxa2xx-mmci)
>     +      /pxa2xx-mmci[0] (qemu:memory-region)
>     +      /sd-bus (pxa2xx-mmci-bus)
>          [rest of device[*] renumbered...]
> 
> Fixes: 7a9468c92517e19037bfe2272f64f5dadaf9db15
> Cc: Andrzej Zaborowski <balrogg@gmail.com>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: qemu-arm@nongnu.org
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> ---
>  hw/sd/pxa2xx_mmci.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/sd/pxa2xx_mmci.c b/hw/sd/pxa2xx_mmci.c
> index f9c50ddda5..c32df1b8f9 100644
> --- a/hw/sd/pxa2xx_mmci.c
> +++ b/hw/sd/pxa2xx_mmci.c
> @@ -492,6 +492,7 @@ PXA2xxMMCIState *pxa2xx_mmci_init(MemoryRegion *sysmem,
>      sysbus_connect_irq(sbd, 0, irq);
>      qdev_connect_gpio_out_named(dev, "rx-dma", 0, rx_dma);
>      qdev_connect_gpio_out_named(dev, "tx-dma", 0, tx_dma);
> +    qdev_init_nofail(dev);
>  
>      /* Create and plug in the sd card */
>      carddev = qdev_create(qdev_get_child_bus(dev, "sd-bus"), TYPE_SD_CARD);
>