Re: [PATCH v2] kvm: Disable MSI/MSI-X in assigned device reset path

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-04-16 19:12, Michael S. Tsirkin wrote:
> On Mon, Apr 16, 2012 at 06:38:22PM +0200, Jan Kiszka wrote:
>> On 2012-04-16 18:36, Michael S. Tsirkin wrote:
>>> On Mon, Apr 16, 2012 at 06:13:03PM +0200, Jan Kiszka wrote:
>>>> On 2012-04-16 18:08, Michael S. Tsirkin wrote:
>>>>> On Mon, Apr 16, 2012 at 05:10:07PM +0200, Jan Kiszka wrote:
>>>>>> On 2012-04-16 17:06, Michael S. Tsirkin wrote:
>>>>>>> On Mon, Apr 16, 2012 at 08:03:17AM -0600, Alex Williamson wrote:
>>>>>>>> The discussion on this patch seems to have fizzled, with no clear short
>>>>>>>> term solution.
>>>>>>>
>>>>>>> I think we are in concensus, it's just that there are
>>>>>>> multiple bugs still left to fix.
>>>>>>>
>>>>>>> First, we need to prevent guest from touching command
>>>>>>> register except for the bus master bit. Something like
>>>>>>
>>>>>> INTx is harmless as well. Denying access breaks masking for the guest.
>>>>>
>>>>> We currently mark intx as emulated, no?
>>>>
>>>> If we use the mask also in the kernel for IRQ sharing, we *monitor* it.
>>>>
>>>>> Anyway - care fixing it properly?
>>>>
>>>> There is nothing to fix.
>>>>
>>>> Jan
>>>
>>> Guest access  to command register is a bug.
>>> E.g. it has no business enabling SERR as SERR crashes
>>> host when triggered.
>>
>> Maybe a misunderstanding. I agree that other bits are not guest
>> business. But INTx should be excluded from this filtering and handled as
>> is, i.e. passed through.
>>
>> Jan
> 
> Ah, I see what you mean.
> So let's add
>     pci_dev->emulate_config_write[PCI_COMMAND + 1] &= ~(PCI_COMMAND_INTX_DISABLE >> 8);
> on top?

Looks good.

Jan

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