Re: [PATCH v2 09/24] macio: Fix to realize "mos6522-cuda" and "mos6522-pmu" devices

From: Peter Maydell <peter.maydell@linaro.org>
To: Markus Armbruster <armbru@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Laurent Vivier <laurent@vivier.eu>,
	"Daniel P. Berrange" <berrange@redhat.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Eduardo Habkost <ehabkost@redhat.com>
Subject: Re: [PATCH v2 09/24] macio: Fix to realize "mos6522-cuda" and "mos6522-pmu" devices
Date: Mon, 8 Jun 2020 15:25:25 +0100	[thread overview]
Message-ID: <CAFEAcA8qWmMfn765D+fXZGqOoDyb59vaha=wsRjhZPiNG7MVkA@mail.gmail.com> (raw)
In-Reply-To: <20200528110444.20456-10-armbru@redhat.com>

On Thu, 28 May 2020 at 12:13, Markus Armbruster <armbru@redhat.com> wrote:
>
> cuda_init() creates a "mos6522-cuda" device, but it's never realized.
> Affects machines mac99 with via=cuda (default) and g3beige.
>
> pmu_init() creates a "mos6522-pmu" device, but it's never realized.
> Affects machine mac99 with via=pmu and via=pmu-adb,
>
> 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.
>
> These onetwo appear 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 them in cuda_realize() and pmu_realize(),
> respectively.
>
> Fixes: 6dca62a0000f95e0b7020aa00d0ca9b2c421f341
> Cc: Laurent Vivier <laurent@vivier.eu>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  hw/misc/macio/cuda.c | 10 +++++-----
>  hw/misc/macio/pmu.c  | 10 +++++-----
>  2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/hw/misc/macio/cuda.c b/hw/misc/macio/cuda.c
> index e0cc0aac5d..763a785f1a 100644
> --- a/hw/misc/macio/cuda.c
> +++ b/hw/misc/macio/cuda.c
> @@ -33,6 +33,7 @@
>  #include "hw/misc/macio/cuda.h"
>  #include "qemu/timer.h"
>  #include "sysemu/runstate.h"
> +#include "qapi/error.h"
>  #include "qemu/cutils.h"
>  #include "qemu/log.h"
>  #include "qemu/module.h"
> @@ -523,15 +524,14 @@ static void cuda_realize(DeviceState *dev, Error **errp)
>  {
>      CUDAState *s = CUDA(dev);
>      SysBusDevice *sbd;
> -    MOS6522State *ms;
> -    DeviceState *d;
>      struct tm tm;
>
> +    object_property_set_bool(OBJECT(&s->mos6522_cuda), true, "realized",
> +                             &error_abort);

Still disagree with barfing on failure when we have a perfectly
good way to return the failure indication.

thanks
-- PMM