Re: [Qemu-devel] [PATCH v3 3/3] pci: enable RedHat PCI bridges to reserve additional buses on PCI init

["Michael S. Tsirkin" <mst@redhat.com>]

On Sat, Jul 29, 2017 at 02:34:32AM +0300, Aleksandr Bezzubikov wrote:
> In case of Red Hat Generic PCIE Root Port reserve additional buses,
> which number is provided in a vendor-specific capability.
> 
> Signed-off-by: Aleksandr Bezzubikov <zuban32s@gmail.com>

Why does this ignore io/memory reserve parts of the capability?

> ---
>  src/fw/pciinit.c | 37 +++++++++++++++++++++++++++++++++++--
>  src/hw/pci_ids.h |  3 +++
>  src/types.h      |  2 ++
>  3 files changed, 40 insertions(+), 2 deletions(-)
> 
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 864954f..a302a85 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -15,6 +15,7 @@
>  #include "hw/pcidevice.h" // pci_probe_devices
>  #include "hw/pci_ids.h" // PCI_VENDOR_ID_INTEL
>  #include "hw/pci_regs.h" // PCI_COMMAND
> +#include "fw/dev-pci.h" // qemu_pci_cap
>  #include "list.h" // struct hlist_node
>  #include "malloc.h" // free
>  #include "output.h" // dprintf
> @@ -578,9 +579,41 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
>          pci_bios_init_bus_rec(secbus, pci_bus);
>  
>          if (subbus != *pci_bus) {
> +            u8 res_bus = 0;
> +            if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
> +                    pci_config_readw(bdf, PCI_DEVICE_ID) ==
> +                            PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
> +                u8 cap;
> +                do {
> +                    cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);
> +                } while (cap &&
> +                         pci_config_readb(bdf, cap + PCI_CAP_VNDR_SPEC_TYPE) !=
> +                                REDHAT_CAP_TYPE_QEMU);
> +                if (cap) {
> +                    u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
> +                    if (cap_len != QEMU_PCI_CAP_SIZE) {
> +                        dprintf(1, "PCI: QEMU cap length %d is invalid\n",
> +                                cap_len);
> +                    } else {
> +                        res_bus = pci_config_readb(bdf,
> +                                                   cap + QEMU_PCI_CAP_BUS_RES);
> +                        if ((u8)(res_bus + secbus) < secbus ||
> +                            (u8)(res_bus + secbus) < res_bus) {
> +                            dprintf(1, "PCI: bus_reserve value %d is invalid\n",
> +                                    res_bus);
> +                            res_bus = 0;
> +                        } else {
> +                            dprintf(1, "PCI: QEMU cap is found, value = %u\n",
> +                                    res_bus);
> +                        }
> +                    }
> +                }
> +                res_bus = MAX(*pci_bus, secbus + res_bus);
> +            }
>              dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",
> -                    subbus, *pci_bus);
> -            subbus = *pci_bus;
> +                    subbus, res_bus);
> +            subbus = res_bus;
> +            *pci_bus = res_bus;
>          } else {
>              dprintf(1, "PCI: subordinate bus = 0x%x\n", subbus);
>          }
> diff --git a/src/hw/pci_ids.h b/src/hw/pci_ids.h
> index 4ac73b4..38fa2ca 100644
> --- a/src/hw/pci_ids.h
> +++ b/src/hw/pci_ids.h
> @@ -2263,6 +2263,9 @@
>  #define PCI_DEVICE_ID_KORENIX_JETCARDF0	0x1600
>  #define PCI_DEVICE_ID_KORENIX_JETCARDF1	0x16ff
>  
> +#define PCI_VENDOR_ID_REDHAT		0x1b36
> +#define PCI_DEVICE_ID_REDHAT_ROOT_PORT	0x000C
> +
>  #define PCI_VENDOR_ID_TEKRAM		0x1de1
>  #define PCI_DEVICE_ID_TEKRAM_DC290	0xdc29
>  
> diff --git a/src/types.h b/src/types.h
> index 19d9f6c..75d9108 100644
> --- a/src/types.h
> +++ b/src/types.h
> @@ -122,6 +122,8 @@ extern void __force_link_error__only_in_16bit(void) __noreturn;
>              typeof(divisor) __divisor = divisor;        \
>              (((x) + ((__divisor) / 2)) / (__divisor));  \
>          })
> +#define MIN(a, b) (((a) < (b)) ? (a) : (b))
> +#define MAX(a, b) (((a) > (b)) ? (a) : (b))
>  #define ALIGN(x,a)              __ALIGN_MASK(x,(typeof(x))(a)-1)
>  #define __ALIGN_MASK(x,mask)    (((x)+(mask))&~(mask))
>  #define ALIGN_DOWN(x,a)         ((x) & ~((typeof(x))(a)-1))
> -- 
> 2.7.4