[Qemu-devel] Re: [PATCH v2 0/6] qdev reset refactoring and pci bus reset

[Isaku Yamahata <yamahata@valinux.co.jp>]

On Wed, Nov 24, 2010 at 07:27:58AM +0200, Michael S. Tsirkin wrote:
> Right. So let's add an inline helper to avoid code duplication here?
> 
> pci: fix bus walk under secondary bus reset
> 
> Take into account secondary bus reset bit for
> bus walk: devices behind a reset bus should not
> respond to configuration cycles.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> 
> diff --git a/hw/pci.c b/hw/pci.c
> index d02f980..0c15b13 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -1540,6 +1540,16 @@ void pci_bridge_update_mappings(PCIBus *b)
>      }
>  }
>  
> +/* Whether a given bus number is in range of the secondary
> + * bus of the given bridge device. */
> +static bool pci_secondary_bus_in_range(PCIDevice *dev, int bus_num)
> +{
> +    return !(pci_get_word(dev->config + PCI_BRIDGE_CONTROL) &
> +             PCI_BRIDGE_CTL_BUS_RESET) /* Don't walk the bus if it's reset. */ &&
> +        dev->config[PCI_SECONDARY_BUS] < bus_num &&
> +        bus_num <= dev->config[PCI_SUBORDINATE_BUS];
> +}
> +
>  PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
>  {
>      PCIBus *sec;
> @@ -1552,20 +1562,21 @@ PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
>          return bus;
>      }
>  
> +    /* Consider all bus numbers in range for the host pci bridge. */
> +    if (bus->parent_dev &&
> +        !pci_secondary_bus_in_range(bus->parent_dev, bus_num)) {
> +        return NULL;
> +    }
> +
>      /* try child bus */
> -    if (!bus->parent_dev /* host pci bridge */ ||
> -        (bus->parent_dev->config[PCI_SECONDARY_BUS] < bus_num &&
> -         bus_num <= bus->parent_dev->config[PCI_SUBORDINATE_BUS])) {
> -        for (; bus; bus = sec) {
> -            QLIST_FOREACH(sec, &bus->child, sibling) {
> -                assert(sec->parent_dev);
> -                if (sec->parent_dev->config[PCI_SECONDARY_BUS] == bus_num) {
> -                    return sec;
> -                }
> -                if (sec->parent_dev->config[PCI_SECONDARY_BUS] < bus_num &&
> -                    bus_num <= sec->parent_dev->config[PCI_SUBORDINATE_BUS]) {
> -                    break;
> -                }
> +    for (; bus; bus = sec) {
> +        QLIST_FOREACH(sec, &bus->child, sibling) {
> +            assert(sec->parent_dev);
> +            if (sec->parent_dev->config[PCI_SECONDARY_BUS] == bus_num) {
> +                return sec;
> +            }
> +            if (pci_secondary_bus_in_range(sec->parent_dev, bus_num)) {

This condition should be "if (!pci_...)"


> +                break;
>              }
>          }
>      }
> 
> > -- 
> > yamahata
> 

-- 
yamahata