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

[BALATON Zoltan]

On Tue, 10 Mar 2020, Mark Cave-Ayland wrote:
> 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().

OK will test it and send updated version.

Regards,
BALATON Zoltan