Re: [SeaBIOS] [PATCH v3 3/5] hw/pci: introduce bridge-only vendor-specific capability to provide some hints to firmware

[Marcel Apfelbaum]

On 29/07/2017 2:37, Aleksandr Bezzubikov wrote:
> On PCI init PCI bridges may need some
> extra info about bus number to reserve, IO, memory and
> prefetchable memory limits. QEMU can provide this
> with a special vendor-specific PCI capability.
> Signed-off-by: Aleksandr Bezzubikov
>
> hw/pci/pci_bridge.c         | 37 +++++++++++++++++++++++++++++++++++++
>   include/hw/pci/pci_bridge.h | 28 ++++++++++++++++++++++++++++
>   2 files changed, 65 insertions(+)
>
> diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
> index 720119b..e9f12d6 100644
> --- a/hw/pci/pci_bridge.c
> +++ b/hw/pci/pci_bridge.c
> @@ -408,6 +408,43 @@ void pci_bridge_map_irq(PCIBridge *br, const char* bus_name,
>       br->bus_name = bus_name;
>   }

Hi Alexksander,
> +int pci_bridge_qemu_cap_init(PCIDevice *dev, int cap_offset,
>                          uint8_t bus_reserve, uint32_t io_reserve,
>                          uint16_t non_pref_reserve, uint64_t pref_reserve,
>                          Error **errp)

Maybe we should change it to something like
pci_bridge_res_reseve_cap_init ? Maybe we will
have other caps in the future.
> +{
> size_t cap_len = sizeof(PCIBridgeQemuCap);
> PCIBridgeQemuCap cap = {
>        .len = cap_len,
>        .type = REDHAT_PCI_CAP_QEMU,
>        .bus_res = bus_reserve,
>        .non_pref_16 = non_pref_reserve
> };
> if ((uint8_t)io_reserve == io_reserve) {
>    cap.io_8 = io_reserve;
> } else {
>    cap.io_32 = io_reserve;
> }
> if ((uint16_t)pref_reserve == pref_reserve) {
>    cap.pref_32 = pref_reserve;
> } else {
>    cap.pref_64 = pref_reserve;
> }
> int offset = pci_add_capability(dev, PCI_CAP_ID_VNDR,
>                                cap_offset, cap_len, errp);
> if (offset < 0) {
>    return offset;
> }
> memcpy(dev->config + offset + PCI_CAP_FLAGS,
>        (char *)&cap + PCI_CAP_FLAGS,
>        cap_len - PCI_CAP_FLAGS);
> return 0;
>
> +}
> static const TypeInfo pci_bridge_type_info = {
>     .name = TYPE_PCI_BRIDGE,
>     .parent = TYPE_PCI_DEVICE,
>
> diff --git a/include/hw/pci/pci_bridge.h b/include/hw/pci/pci_bridge.h
> index ff7cbaa..e9b7cf4 100644
> --- a/include/hw/pci/pci_bridge.h
> +++ b/include/hw/pci/pci_bridge.h
> @@ -67,4 +67,32 @@ void pci_bridge_map_irq(PCIBridge *br, const char* bus_name,
>   #define  PCI_BRIDGE_CTL_DISCARD_STATUS	0x400	/* Discard timer status */
>   #define  PCI_BRIDGE_CTL_DISCARD_SERR	0x800	/* Discard timer SERR# enable */
>
> +typedef struct PCIBridgeQemuCap {
> uint8_t id;     /* Standard PCI capability header field */
> uint8_t next;   /* Standard PCI capability header field */
> uint8_t len;    /* Standard PCI vendor-specific capability header field */
> uint8_t type;   /* Red Hat vendor-specific capability type.
>                   Types are defined with REDHAT_PCI_CAP_ prefix */
> uint16_t non_pref_16;   /* Non-prefetchable memory limit */
> uint8_t bus_res;        /* Minimum number of buses to reserve */
> uint8_t io_8;           /* IO space limit in case of 8-bit value */
> uint32_t io_32;         /* IO space limit in case of 32-bit value
>                           This 2 values are mutually exclusive,
>                           i.e. they can't be  >0 both*/
> uint32_t pref_32;       /* Prefetchable memory limit
>                           in case of 32-bit value */
> uint64_t pref_64;       /* Prefetchable memory limit
>                           in case of 64-bit value
>                           This 2 values are mutually exclusive (just as
>                           IO limit), i.e. they can't be  >0 both */

The same comments as for the SeaBIOS series, can the capability
be more simple?
    uint32_t bus_res
    uint32_t io_res
    uint32_t mem_res
    uint32_t pref_32_res
    uint64_t pref_64_res

It is possible I missed some arguments, I'll have another look
on the thread.

Thanks,
Marcel
> +} PCIBridgeQemuCap;
>
> +#define REDHAT_PCI_CAP_QEMU     1
>
> +int pci_bridge_qemu_cap_init(PCIDevice *dev, int cap_offset,
>                          uint8_t bus_reserve, uint32_t io_reserve,
>                          uint16_t mem_reserve, uint64_t pref_reserve,
>                          Error **errp);
> #endif /* QEMU_PCI_BRIDGE_H */