[SeaBIOS] Re: [PATCH v3 2/2] pci: let firmware reserve IO for pcie-pci-bridge

[Laurent Vivier]

On 29/11/2021 12:48, Igor Mammedov wrote:
> With [1] patch hotplug of rtl8139 succeeds, with caveat that it
> fails to initialize IO bar, which is caused by [2] that makes
> firmware skip IO reservation for any PCIe device, which isn't
> correct in case of pcie-pci-bridge.
> Fix it by exposing hotplug type and making IO resource optional
> only if PCIe hotplug is in use.
>
> [1]
>   "pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35"
> [2]
> Fixes: 76327b9f32a ("fw/pci: do not automatically allocate IO region for PCIe bridges")
> Signed-off-by: Igor Mammedov [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
>
> src/fw/pciinit.c | 19 ++++++++++++++-----
>   1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 7342d8d8..badf13d3 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -793,7 +793,13 @@ 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)
> +typedef enum hotplug_type_t {
> HOTPLUG_NO_SUPPORTED = 0,
> HOTPLUG_PCIE,
> HOTPLUG_SHPC
>
> +} hotplug_type_t;
>
> +static hotplug_type_t pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>   {
>       u8 shpc_cap;
>
> @@ -819,12 +825,13 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>            */
>           u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;
>    return downstream_port && slot_implemented;
>    return downstream_port && slot_implemented ?
>        HOTPLUG_PCIE : HOTPLUG_NO_SUPPORTED;
> }
>
> check_shpc:
>     shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
> return !!shpc_cap;
>
> return !!shpc_cap ? HOTPLUG_SHPC : HOTPLUG_NO_SUPPORTED;
> }
>
> /* Test whether bridge support forwarding of transactions
>
> @@ -909,7 +916,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>           u8 pcie_cap = pci_find_capability(bdf, PCI_CAP_ID_EXP, 0);
>           u8 qemu_cap = pci_find_resource_reserve_capability(bdf);
>    int hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
>    hotplug_type_t hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
>     for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
>         u64 align = (type == PCI_REGION_TYPE_IO) ?
>             PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
>
> @@ -953,7 +960,9 @@ 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]);
>        int resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
>        int resource_optional = 0;
>        if (hotplug_support == HOTPLUG_PCIE)
>            resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
>         if (!sum && hotplug_support && !resource_optional)
>             sum = align; /* reserve min size for hot-plug */
>         if (size > sum) {

Tested-by: Laurent Vivier