On Wed, Nov 03, 2021 at 11:02:37AM +0000, Oleksandr Andrushchenko wrote:
>
>
> On 03.11.21 13:01, Roger Pau Monné wrote:
> > On Wed, Nov 03, 2021 at 10:36:36AM +0000, Oleksandr Andrushchenko wrote:
> >>
> >> On 03.11.21 12:34, Jan Beulich wrote:
> >>> On 03.11.2021 11:24, Oleksandr Andrushchenko wrote:
> >>>> On 03.11.21 11:49, Jan Beulich wrote:
> >>>>> Aiui you want to prevent the guest from clearing the bit if either
> >>>>> MSI or MSI-X are in use. Symmetrically, when the guest enables MSI
> >>>>> or MSI-X, you will want to force the bit set (which may well be in
> >>>>> a separate, future patch).
> >>>> static uint32_t emulate_cmd_reg(const struct pci_dev *pdev, uint32_t cmd)
> >>>> {
> >>>> /* TODO: Add proper emulation for all bits of the command
> >>>> register. */
> >>>>
> >>>> if ( (cmd & PCI_COMMAND_INTX_DISABLE) == 0 )
> >>>> {
> >>>> /* Guest wants to enable INTx. It can't be enabled if
> >>>> MSI/MSI-X enabled. */
> >>>> #ifdef CONFIG_HAS_PCI_MSI
> >>>> if ( pdev->vpci->msi->enabled )
> >>>> cmd |= PCI_COMMAND_INTX_DISABLE;
> >>>> #endif
> >>>> }
> >>>>
> >>>> return cmd;
> >>>> }
> >>>>
> >>>> Is this what you mean?
> >>> Something along these lines, yes. I'd omit the outer if() for clarity /
> >>> brevity.
> >> Sure, thank you!
> >> @Roger are you ok with this approach?
> > Sure, I would even do:
> >
> > #ifdef CONFIG_HAS_PCI_MSI
> > if ( !(cmd & PCI_COMMAND_INTX_DISABLE) && pdev->vpci->msi->enabled )
> > {
> > /* Guest wants to enable INTx. It can't be enabled if MSI/MSI-X
> > enabled. */
> > cmd |= PCI_COMMAND_INTX_DISABLE;
> > }
> > #endif
> >
> > There's no need for the outer check if there's no support for MSI.
> Ok, sounds good!
> Thank you both!!
In fact you could even remove the check for !(cmd &
PCI_COMMAND_INTX_DISABLE) and always set PCI_COMMAND_INTX_DISABLE if
MSI is enabled, which I think is what Jan was pointing to in his
previous reply.
Regards, Roger.
