Re: [Qemu-devel] [PATCH 2/7] megasas: Enable MSI-X support

[Andreas Färber]

Am 16.04.2014 19:40, schrieb Michael S. Tsirkin:
> On Wed, Apr 16, 2014 at 06:48:08PM +0200, Andreas Färber wrote:
>> Am 16.04.2014 18:32, schrieb Alexander Graf:
>>>
>>> On 16.04.14 16:44, Hannes Reinecke wrote:
>>>> MSI-X support has been fixed in qemu, so we can enable it again.
>>>>
>>>> Signed-off-by: Hannes Reinecke <address@hidden>
>>>> ---
>>>>   hw/scsi/megasas.c | 19 ++++++-------------
>>>>   1 file changed, 6 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
>>>> index 1781525..df45286 100644
>>>> --- a/hw/scsi/megasas.c
>>>> +++ b/hw/scsi/megasas.c
>>>> @@ -2084,7 +2084,8 @@ static const VMStateDescription vmstate_megasas = {
>>>>       .minimum_version_id = 0,
>>>>       .minimum_version_id_old = 0,
>>>>       .fields      = (VMStateField[]) {
>>>> -        VMSTATE_PCI_DEVICE(parent_obj, MegasasState),
>>>> +        VMSTATE_PCIE_DEVICE(parent_obj, MegasasState),
>>>> +        VMSTATE_MSIX(parent_obj, MegasasState),
>>>
>>> This requires a version change for vmstate, no?
>>
>> The PCI -> PCIE change yes. mst might have objections for bumping an x86
>> PCI device?
> 
> Yes.
> It should be possible to make this conditional on having a pcie
> capability, and disable pcie capability for old pc versions.

I did have a patch merging their vmstate_ structs based on some test in
the series I ping'ed, unfortunately the difference was mostly config
space size, so not immediately obvious how to set via compat_props, but
likely solvable somehow.

>> The MSIX addition should be safe AFAICT since old versions would not
>> enable MSI-X.
> 
> Yes but I don't see a code like this - where's code in PC
> disabling msix for old versions?

The default value for use_msix (use-msix?) in v2 is already false, so no
need to set it to false again in compat_props?

Andreas

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