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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
Cc: "Hervé Poussineau" <hpoussin@reactos.org>,
	qemu-devel@nongnu.org, "Aurelien Jarno" <aurelien@aurel32.net>
Subject: Re: [PATCH v2] hw/isa/piix4: Migrate Reset Control Register
Date: Wed, 24 Mar 2021 19:40:09 +0000	[thread overview]
Message-ID: <YFuVmTJcsdXj1UrG@work-vm> (raw)
In-Reply-To: <20210324192731.717142-1-f4bug@amsat.org>

* Philippe Mathieu-Daudé (f4bug@amsat.org) wrote:
> When adding the Reset register in commit 5790b757cfb we
> forgot to migrate it.
> 
> While it is possible a VM using the PIIX4 is migrated just
> after requesting a system shutdown, it is very unlikely.
> However when restoring a migrated VM, we might have the
> RCR bit #4 set on the stack and when the VM resume it
> directly shutdowns.
> 
> Add a post_load() migration handler and set the default
> RCR value to 0 for earlier versions, assuming the VM was
> not going to shutdown before migration.
> 
> Fixes: 5790b757cfb ("piix4: Add the Reset Control Register")
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> v2: Add piix4_ide_post_load() and describe
> ---
>  hw/isa/piix4.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
> index a50d97834c7..e7bce0e590c 100644
> --- a/hw/isa/piix4.c
> +++ b/hw/isa/piix4.c
> @@ -93,12 +93,25 @@ static void piix4_isa_reset(DeviceState *dev)
>      pci_conf[0xae] = 0x00;
>  }
>  
> +static int piix4_ide_post_load(void *opaque, int version_id)
> +{
> +    PIIX4State *s = opaque;
> +
> +    if (version_id == 2) {
> +        s->rcr = 0;
> +    }
> +
> +    return 0;
> +}
> +
>  static const VMStateDescription vmstate_piix4 = {
>      .name = "PIIX4",
> -    .version_id = 2,
> +    .version_id = 3,
>      .minimum_version_id = 2,
> +    .post_load = piix4_ide_post_load,
>      .fields = (VMStateField[]) {
>          VMSTATE_PCI_DEVICE(dev, PIIX4State),
> +        VMSTATE_UINT8(rcr, PIIX4State),

I don't think that looks right any more; you'd need to make that a 
   VMSTATE_UINT8_V(rcr, PIIX4State, 3),

I think, otherwise when you loaded a v2 it would still try
and read the rcr byte.

Dave

>          VMSTATE_END_OF_LIST()
>      }
>  };
> -- 
> 2.26.2
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK



  reply	other threads:[~2021-03-24 19:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 19:27 [PATCH v2] hw/isa/piix4: Migrate Reset Control Register Philippe Mathieu-Daudé
2021-03-24 19:40 ` Dr. David Alan Gilbert [this message]
2021-03-24 20:00   ` Philippe Mathieu-Daudé

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