Re: [SeaBIOS] [PATCH v3] hw/pci: reserve IO and mem for pci express downstream ports with no devices attached

[Michael S. Tsirkin]

On Mon, Jun 23, 2014 at 06:29:51PM +0300, Marcel Apfelbaum wrote:
> Commit c6e298e1f12e0f4ca02b6da5e42919ae055f6830
>     hw/pci: reserve IO and mem for pci-2-pci bridges with no devices attached
>
> introduced support for hot-plugging devices behind pci-2-pci bridges.
> Extend hotplug support also for pci express downstream ports.
>
> Signed-off-by: Marcel Apfelbaum

Reviewed-by: Michael S. Tsirkin

Gerd, is there a plan to do a release for QEMU 2.1?
It would be nice to have this patch there.

Thanks,
> v2 -> v3:
>  Addressed Michael S. Tsirkin comments:
> Refactored pci_bus_hotplug_support function.
> Removed PCI_EXP_FLAGS_TYPE_SHIFT macro.
>
> v1 -> v2:
>  Wrong prefix on first patch.
>
> src/fw/pciinit.c | 34 ++++++++++++++++++++++++++++++++--
>  1 file changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 0ad548f..fd5dfb9 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -636,6 +636,36 @@ pci_region_create_entry(struct pci_bus *bus, struct pci_device *dev,
>      return entry;
>  }
>
> +static int pci_bus_hotplug_support(struct pci_bus *bus)
> +{
> u8 pcie_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_EXP);
> u8 shpc_cap;
> if (pcie_cap) {
>    u16 pcie_flags = pci_config_readw(bus->bus_dev->bdf,
>                                      pcie_cap + PCI_EXP_FLAGS);
>    u8 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
>                   (__builtin_ffs(PCI_EXP_FLAGS_TYPE) - 1));
>    u8 downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
>                         (port_type == PCI_EXP_TYPE_ROOT_PORT);
>    /*
>     * PCI Express SPEC, 7.8.2:
>     *   Slot Implemented – When Set, this bit indicates that the Link
>     *   HwInit associated with this Port is connected to a slot (as
>     *   compared to being connected to a system-integrated device or
>     *   being disabled).
>     *   This bit is valid for Downstream Ports. This bit is undefined
>     *   for Upstream Ports.
>     */
>    u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;
>    return downstream_port && slot_implemented;
> }
> shpc_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_SHPC);
> return !!shpc_cap;
>
> +}
>
> static int pci_bios_check_devices(struct pci_bus *busses)
>  {
>      dprintf(1, "PCI: check devices\n");
> @@ -678,7 +708,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>              continue;
>          struct pci_bus *parent = &busses[pci_bdf_to_bus(s->bus_dev->bdf)];
>          int type;
>    u8 shpc_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_SHPC);
>    int hotplug_support = pci_bus_hotplug_support(s);
>    for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
>        u64 align = (type == PCI_REGION_TYPE_IO) ?
>            PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
>
> @@ -687,7 +717,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>              if (pci_region_align(&s->r[type]) > align)
>                   align = pci_region_align(&s->r[type]);
>              u64 sum = pci_region_sum(&s->r[type]);
>        if (!sum && shpc_cap)
>        if (!sum && hotplug_support)
>            sum = align; /* reserve min size for hot-plug */
>        u64 size = ALIGN(sum, align);
>        int is64 = pci_bios_bridge_region_is64(&s->r[type],