Re: [SeaBIOS] [PATCH] pci: fix 'io hints' capability for RedHat PCI bridges

[Michael S. Tsirkin]

On Thu, Jan 11, 2018 at 10:15:12PM +0200, Marcel Apfelbaum wrote:
> Commit ec6cb17f (pci: enable RedHat PCI bridges to reserve additional
>                  resources on PCI init)
> added a new vendor specific PCI capability for RedHat PCI bridges
> allowing them to reserve additional buses and/or IO/MEM space.
>
> When adding the IO hints PCI capability to the pcie-root-port
> without specifying a value for bus reservation, the subordinate bus
> computation is wrong and the guest kernel gets messed up.
>
> Fix it by returning to prev code if the value for bus
> reservation is not set.
>
> Removed also a wrong debug print "PCI: invalid QEMU resource reserve
> cap offset" which appears if the 'IO hints' capability is not present.
>
> Signed-off-by: Marcel Apfelbaum

Acked-by: Michael S. Tsirkin
> src/fw/pciinit.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 7f0e439..3a2f747 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -540,8 +540,6 @@ static u8 pci_find_resource_reserve_capability(u16 bdf)
>                  dprintf(1, "PCI: QEMU resource reserve cap length %d is invalid\n",
>                          cap_len);
>              }
>    } else {
>        dprintf(1, "PCI: invalid QEMU resource reserve cap offset\n");
>    }
>    return cap;
> } else {
>
> @@ -619,13 +617,11 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
>                                  res_bus);
>                          res_bus = 0;
>                      }
>            }
>            if (secbus + res_bus > *pci_bus) {
>                dprintf(1, "PCI: QEMU resource reserve cap: bus = %u\n",
>                        res_bus);
>                res_bus = secbus + res_bus;
>            } else {
>                res_bus = *pci_bus;
>                if (secbus + res_bus > *pci_bus) {
>                    dprintf(1, "PCI: QEMU resource reserve cap: bus = %u\n",
>                            res_bus);
>                    res_bus = secbus + res_bus;
>                }
>            }
>        }
>        dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",