* [PATCH v2] hw/isa/piix4: Migrate Reset Control Register
@ 2021-03-24 19:27 Philippe Mathieu-Daudé
2021-03-24 19:40 ` Dr. David Alan Gilbert
0 siblings, 1 reply; 3+ messages in thread
From: Philippe Mathieu-Daudé @ 2021-03-24 19:27 UTC (permalink / raw)
To: qemu-devel
Cc: Hervé Poussineau, Philippe Mathieu-Daudé,
Aurelien Jarno, Dr . David Alan Gilbert
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),
VMSTATE_END_OF_LIST()
}
};
--
2.26.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] hw/isa/piix4: Migrate Reset Control Register
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
2021-03-24 20:00 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2021-03-24 19:40 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: Hervé Poussineau, qemu-devel, Aurelien Jarno
* 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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] hw/isa/piix4: Migrate Reset Control Register
2021-03-24 19:40 ` Dr. David Alan Gilbert
@ 2021-03-24 20:00 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 3+ messages in thread
From: Philippe Mathieu-Daudé @ 2021-03-24 20:00 UTC (permalink / raw)
To: Dr. David Alan Gilbert; +Cc: Hervé Poussineau, qemu-devel, Aurelien Jarno
On 3/24/21 8:40 PM, Dr. David Alan Gilbert wrote:
> * 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.
Ah now I guess I understood.
Thanks!
^ permalink raw reply [flat|nested] 3+ messages in thread
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