[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v5 11/14] vpci: add initial support for virtual PCI bus topology
On 25.11.2021 12:02, Oleksandr Andrushchenko wrote: > @@ -145,6 +148,53 @@ int vpci_add_handlers(struct pci_dev *pdev) > } > > #ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > +int vpci_add_virtual_device(struct pci_dev *pdev) > +{ > + struct domain *d = pdev->domain; > + pci_sbdf_t sbdf = { 0 }; > + unsigned long new_dev_number; > + > + /* > + * Each PCI bus supports 32 devices/slots at max or up to 256 when > + * there are multi-function ones which are not yet supported. > + */ > + if ( pdev->info.is_extfn ) > + { > + gdprintk(XENLOG_ERR, "%pp: only function 0 passthrough supported\n", > + &pdev->sbdf); > + return -EOPNOTSUPP; > + } > + > + new_dev_number = find_first_zero_bit(&d->vpci_dev_assigned_map, > + VPCI_MAX_VIRT_DEV); > + if ( new_dev_number >= VPCI_MAX_VIRT_DEV ) > + return -ENOSPC; > + > + __set_bit(new_dev_number, &d->vpci_dev_assigned_map); > + > + /* > + * Both segment and bus number are 0: > + * - we emulate a single host bridge for the guest, e.g. segment 0 > + * - with bus 0 the virtual devices are seen as embedded > + * endpoints behind the root complex > + * > + * TODO: add support for multi-function devices. > + */ > + sbdf.devfn = PCI_DEVFN(new_dev_number, 0); > + pdev->vpci->guest_sbdf = sbdf; > + > + return 0; > + > +} > +REGISTER_VPCI_INIT(vpci_add_virtual_device, VPCI_PRIORITY_MIDDLE); Is this function guaranteed to always be invoked ahead of ... > +static void vpci_remove_virtual_device(struct domain *d, > + const struct pci_dev *pdev) > +{ > + __clear_bit(pdev->vpci->guest_sbdf.dev, &d->vpci_dev_assigned_map); > + pdev->vpci->guest_sbdf.sbdf = ~0; > +} ... this one, even when considering error paths? Otherwise you may wrongly clear bit 31 here afaict. Jan
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