Re: [Qemu-devel] [PATCH for-4.0] spapr_pci: Fix broken naming of PCI bus

[David Gibson]

On Thu, Apr 11, 2019 at 06:32:24PM +0200, Greg Kurz wrote:
> Recent commit 5cf0d326a0fe fixed a regression which was preventing the
> guest to access the extended config space of a PCIe device. This was
> done by introducing a new PCI bus subtype for PAPR. The original fix
> was causing PCI busses to be named "spapr-pci-host-bridge-root-bus.N"
> instead of "pci.N", which was making upper layers unhappy of course.
> This got worked around by hardcoding the PCI bus name to "pci.0", but
> this only works for the default PHB. And we're now hitting:
> 
> # qemu-system-ppc64 \
>              -device spapr-pci-host-bridge,index=1 \
>              -device e1000e,bus=pci.0 \
>              -device e1000e,bus=pci.1
> qemu-system-ppc64: -device e1000e,bus=pci.1: Bus 'pci.1' not found
> 
> David already posted some patches [1] to control PCI extended config
> space accesses with a new flag in the base PCI bus class instead of
> subtyping. These patches are a bit more intrusive though, and
> are targetted for 4.1.
> 
> When no name is passed to pci_register_bus(), the core device code
> generates a lowercase name based on the QOM typename. The typename
> for the base PCI bus class is "PCI", hence the "pci.0", "pci.1"
> bus names. Rename the type of the PAPR PCI bus to "pci", so that
> the QOM code can generate proper names. This is a hack but it is
> enough to fix the regression. And all this will be reworked properly
> in 4.1.
> 
> [1] https://patchwork.ozlabs.org/project/qemu-devel/list/?series=100486
> 
> Fixes: 5cf0d326a0fe
> Signed-off-by: Greg Kurz <address@hidden>

Oof.  That's a hack-and-a-half.  But, I don't see a better way of
fixing this quickly, and as you say, I already have clean ups for this
ready to go for 4.1.  Applied to ppc-for-4.0, and I'll try to rush out
a pull request today.

> ---
>  hw/ppc/spapr_pci.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index f0b6b23afc9b..f62e6833b8c9 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1652,7 +1652,7 @@ static void spapr_phb_root_bus_class_init(ObjectClass 
> *klass, void *data)
>      pbc->allows_extended_config_space = 
> spapr_phb_allows_extended_config_space;
>  }
>  
> -#define TYPE_SPAPR_PHB_ROOT_BUS "spapr-pci-host-bridge-root-bus"
> +#define TYPE_SPAPR_PHB_ROOT_BUS "pci"
>  
>  static const TypeInfo spapr_phb_root_bus_info = {
>      .name = TYPE_SPAPR_PHB_ROOT_BUS,
> @@ -1761,7 +1761,7 @@ static void spapr_phb_realize(DeviceState *dev, Error 
> **errp)
>      memory_region_add_subregion(get_system_memory(), sphb->io_win_addr,
>                                  &sphb->iowindow);
>  
> -    bus = pci_register_root_bus(dev, "pci.0",
> +    bus = pci_register_root_bus(dev, NULL,
>                                  pci_spapr_set_irq, pci_spapr_map_irq, sphb,
>                                  &sphb->memspace, &sphb->iospace,
>                                  PCI_DEVFN(0, 0), PCI_NUM_PINS,
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

signature.asc
Description: PGP signature