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Re: [PATCH v2] hw/isa/piix4: Migrate Reset Control Register
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH v2] hw/isa/piix4: Migrate Reset Control Register |
Date: |
Wed, 24 Mar 2021 19:40:09 +0000 |
User-agent: |
Mutt/2.0.5 (2021-01-21) |
* 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