Re: [PATCH v3 2/3] pci: Honour wmask when resetting PCI_INTERRUPT_LINE

[Mark Cave-Ayland]

On 09/03/2020 20:54, BALATON Zoltan wrote:

> On Mon, 9 Mar 2020, Michael S. Tsirkin wrote:
>> On Mon, Mar 09, 2020 at 08:18:13PM +0100, BALATON Zoltan wrote:
>>> The pci_do_device_reset() function (called from pci_device_reset)
>>> clears the PCI_INTERRUPT_LINE config reg of devices on the bus but did
>>> this without taking wmask into account. We'll have a device model now
>>> that needs to set a constant value for this reg and this patch allows
>>> to do that without additional workaround in device emulation to
>>> reverse the effect of this PCI bus reset function.
>>>
>>> Suggested-by: Mark Cave-Ayland <address@hidden>
>>> Signed-off-by: BALATON Zoltan <address@hidden>
>>> ---
>>>  hw/pci/pci.c | 4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>>> index e1ed6677e1..d07e4ed9de 100644
>>> --- a/hw/pci/pci.c
>>> +++ b/hw/pci/pci.c
>>> @@ -302,8 +302,10 @@ static void pci_do_device_reset(PCIDevice *dev)
>>>      pci_word_test_and_clear_mask(dev->config + PCI_STATUS,
>>>                                   pci_get_word(dev->wmask + PCI_STATUS) |
>>>                                   pci_get_word(dev->w1cmask + PCI_STATUS));
>>> +    pci_word_test_and_clear_mask(dev->config + PCI_INTERRUPT_LINE,
>>> +                              pci_get_word(dev->wmask + 
>>> PCI_INTERRUPT_LINE) |
>>> +                              pci_get_word(dev->w1cmask + 
>>> PCI_INTERRUPT_LINE));
>>
>> PCI spec says:
>>
>> Interrupt Line
>> The Interrupt Line register is an eight-bit register used to communicate 
>> interrupt
>> line routing
>> information.
>>
>> I don't see how it makes sense to access it as a word.
> 
> Patch actually comes from Mark, I don't know. Should we change it to
> pci_byte_test_and_clear_mask or what's the appropriate way here?

Ooops yes it should pci_byte_test_and_clear_mask(). Clearly I got a bit too 
excited
from copying the existing examples in pci_do_device_reset().


ATB,

Mark.