On Wed, Jul 21, 2021 at 08:53:36AM +0800, Boqun Feng wrote: > Currently we retrieve the PCI domain number of the host bridge from the > bus sysdata (or pci_config_window if PCI_DOMAINS_GENERIC=y). Actually > we have the information at PCI host bridge probing time, and it makes > sense that we store it into pci_host_bridge. One benefit of doing so is > the requirement for supporting PCI on Hyper-V for ARM64, because the > host bridge of Hyper-V doesn't have pci_config_window, whereas ARM64 is > a PCI_DOMAINS_GENERIC=y arch, so we cannot retrieve the PCI domain > number from pci_config_window on ARM64 Hyper-V guest. > > As the preparation for ARM64 Hyper-V PCI support, we introduce the > domain_nr in pci_host_bridge and a sentinel value to allow drivers to > set domain numbers properly at probing time. Currently > CONFIG_PCI_DOMAINS_GENERIC=y archs are only users of this > newly-introduced field. > > Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx> > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > --- > drivers/pci/probe.c | 6 +++++- > include/linux/pci.h | 10 ++++++++++ > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 79177ac37880..60c50d4f156f 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -594,6 +594,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge) > bridge->native_pme = 1; > bridge->native_ltr = 1; > bridge->native_dpc = 1; > + bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET; > > device_initialize(&bridge->dev); > } > @@ -898,7 +899,10 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) > bus->ops = bridge->ops; > bus->number = bus->busn_res.start = bridge->busnr; > #ifdef CONFIG_PCI_DOMAINS_GENERIC > - bus->domain_nr = pci_bus_find_domain_nr(bus, parent); > + if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET) > + bus->domain_nr = pci_bus_find_domain_nr(bus, parent); > + else > + bus->domain_nr = bridge->domain_nr; > #endif > > b = pci_find_bus(pci_domain_nr(bus), bridge->busnr); > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 540b377ca8f6..ba61f4e144aa 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -526,6 +526,15 @@ static inline int pci_channel_offline(struct pci_dev *pdev) > return (pdev->error_state != pci_channel_io_normal); > } > > +/* > +* Currently in ACPI spec, for each PCI host bridge, PCI Segment Group number is > +* limited to a 16-bit value, therefore (int)-1 is not a valid PCI domain number, > +* and can be used as a sentinel value indicating ->domain_nr is not set by the > +* driver (and CONFIG_PCI_DOMAINS_GENERIC=y archs will set it with > +* pci_bus_find_domain_nr()). > +*/ Hmm.. I forgot to fix this part. Just fixed it locally. Apologies... Lorenzo, how does the rest look to you? If you think they are good to take then I can send a updated version of this patch #1 (version 5.2 maybe), otherwise (if you think more reviews are needed), I will wait and resolve other feedbacks (if any) and put the updated patch #1 into next iteration (maybe after next -rc is out). Thanks! Just in case, this is the link for the whole series: https://lore.kernel.org/lkml/20210720134429.511541-1-boqun.feng@xxxxxxxxx/ Regards, Boqun > +#define PCI_DOMAIN_NR_NOT_SET (-1) > + > struct pci_host_bridge { > struct device dev; > struct pci_bus *bus; /* Root bus */ > @@ -533,6 +542,7 @@ struct pci_host_bridge { > struct pci_ops *child_ops; > void *sysdata; > int busnr; > + int domain_nr; > struct list_head windows; /* resource_entry */ > struct list_head dma_ranges; /* dma ranges resource list */ > u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */ > -- > 2.30.2 >
