From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:45096)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Ui6m8-000263-CF
	for qemu-devel@nongnu.org; Thu, 30 May 2013 13:36:38 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Ui6m1-0002EY-R1
	for qemu-devel@nongnu.org; Thu, 30 May 2013 13:36:32 -0400
Received: from mx1.redhat.com ([209.132.183.28]:7921)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Ui6m1-0002EK-IV
	for qemu-devel@nongnu.org; Thu, 30 May 2013 13:36:25 -0400
Date: Thu, 30 May 2013 20:36:47 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20130530173647.GA29091@redhat.com>
References: <1369920427-18274-1-git-send-email-mst@redhat.com>
	<1369920427-18274-2-git-send-email-mst@redhat.com>
	<51A76ACF.9050800@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <51A76ACF.9050800@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 1/3] pvpanic: use FWCfgState explicitly
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Laszlo Ersek <lersek@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org, Hu Tao <hutao@cn.fujitsu.com>

On Thu, May 30, 2013 at 05:05:51PM +0200, Laszlo Ersek wrote:
> On 05/30/13 15:27, Michael S. Tsirkin wrote:
> > Use the type-safe FWCfgState structure instead
> > of the unsafe void *.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  hw/misc/pvpanic.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/hw/misc/pvpanic.c b/hw/misc/pvpanic.c
> > index 31e1b1d..1483f27 100644
> > --- a/hw/misc/pvpanic.c
> > +++ b/hw/misc/pvpanic.c
> > @@ -90,7 +90,7 @@ static int pvpanic_isa_initfn(ISADevice *dev)
> >  {
> >      PVPanicState *s = ISA_PVPANIC_DEVICE(dev);
> >      static bool port_configured;
> > -    void *fw_cfg;
> > +    FWCfgState *fw_cfg;
> >  
> >      memory_region_init_io(&s->io, &pvpanic_ops, s, "pvpanic", 1);
> >      isa_register_ioport(dev, &s->io, s->ioport);
> > 
> 
> Doesn't this break your build? Lower down in the function there's
> 
>         fw_cfg = object_resolve_path("/machine/fw_cfg", NULL);
> 
> and object_resolve_path() returns a pointer-to-Object, not
> pointer-to-FWCfgState.

I see, I think I should reorder the patches.

> But for starters I'm quite confused about how the unpatched function
> works. What it does amounts to:
> 
>   fw_cfg_add_file(object_resolve_path(...), ...);
> 
> But, again object_resolve_path() returns pointer-to-Object. I'm checking
> "struct Object" in "include/qom/object.h", and it suggests that derived
> structs should embed Object as first member. However FWCfgState is *not*
> such a derived member. What's going on here?
> 
> http://thread.gmane.org/gmane.comp.emulators.qemu/201544/focus=201564
> http://thread.gmane.org/gmane.comp.emulators.qemu/204452/focus=204450
> 
> Laszlo