[Skiboot] [PATCH 3/3] platforms/qemu: Add slot table entries for a PCIe switch

[Cédric Le Goater]

On 05/11/2019 08:43, Oliver O'Halloran wrote:
> Add a more complex slot table example to the Qemu platform. A more complex
> PCIe topology in qemu is useful for testing and it's simple enough to
> serve as an good example of how to use the slot table construction macros.
> 
> Test in Qemu with:
> 
> ./qemu-system-ppc64 -machine powernv -nographic -m 2G  \
> -bios ./skiboot.lid -kernel ./vmlinux -initrd ./petitfs \
> -device x3130-upstream,id=sw0_up,bus=pcie.2 \
> 	-device xio3130-downstream,id=sw0_down0,chassis=1,slot=0,bus=sw0_up,addr=0 \
> 		-drive file=./disk1.img,format=raw,if=none,id=nvme1 \
> 		-device nvme,drive=nvme1,bus=sw0_down0,serial=1 \
> 	-device xio3130-downstream,id=sw0_down1,chassis=1,slot=1,bus=sw0_up,addr=1 \
> 	-device xio3130-downstream,id=sw0_down2,chassis=1,slot=2,bus=sw0_up,addr=2 \
> 		-device e1000e,bus=sw0_down2
> 
> Results in:
> 
> PHB#0002:00:00.0 [ROOT] 1014 04c1 R:00 C:060400 B:01..05 SLOT=pcie.2
> PHB#0002:01:00.0 [SWUP] 104c 8232 R:02 C:060400 B:02..05 SLOT=sw0_up
> PHB#0002:02:00.0 [SWDN] 104c 8233 R:01 C:060400 B:03..03 SLOT=sw0_down0
> PHB#0002:03:00.0 [EP  ] 8086 5845 R:02 C:010802 (  mass-storage) LOC_CODE=sw0_down0
> PHB#0002:02:01.0 [SWDN] 104c 8233 R:01 C:060400 B:04..04 SLOT=sw0_down1
> PHB#0002:02:02.0 [SWDN] 104c 8233 R:01 C:060400 B:05..05 SLOT=sw0_down2
> PHB#0002:05:00.0 [EP  ] 8086 10d3 R:00 C:020000 (      ethernet) LOC_CODE=sw0_down2
> 
> Cc: Cédric Le Goater <clg at kaod.org>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>


Reviewed-by: Cédric Le Goater <clg at kaod.org>

> ---
> Cedric, should we look at adding something like this to the default
> qemu machine?


Are you talking about defining a default set of PCIe devices for 
the QEMU machine to represent better the HW ? 

We had that in the past but it was very incorrect and the QEMU 
maintainers were asking us to be able to remove all devices with 
the -nodefaults option. I just removed them.

I agree that adding a new default set representing correctly HW
would be useful. Can we agree on a topology ? witherspoon has : 

 - one NIC (pec1)
 - one USB (pec1)
 - one bridge with a SATA device  (pec2)

Thanks,

C. 
 
> ---
>  platforms/qemu/qemu.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/platforms/qemu/qemu.c b/platforms/qemu/qemu.c
> index c73bf255f9b4..e4e7c1815996 100644
> --- a/platforms/qemu/qemu.c
> +++ b/platforms/qemu/qemu.c
> @@ -12,7 +12,16 @@ static bool bt_device_present;
>  
>  ST_PLUGGABLE(qemu_slot0, "pcie.0");
>  ST_PLUGGABLE(qemu_slot1, "pcie.1");
> -ST_PLUGGABLE(qemu_slot2, "pcie.2");
> +
> +static const struct slot_table_entry qemu_sw_down[] = {
> +	SW_PLUGGABLE("sw0_down0", 0x0),
> +	SW_BUILTIN  ("sw0_down1", 0x1),
> +	SW_PLUGGABLE("sw0_down2", 0x2),
> +	{ .etype = st_end },
> +};
> +ST_BUILTIN_DEV(qemu_sw_up,   "sw0_up", .children = qemu_sw_down);
> +ST_BUILTIN_DEV(qemu_sw_root, "pcie.2", .children = qemu_sw_up);
> +
>  ST_PLUGGABLE(qemu_slot3, "pcie.3");
>  ST_PLUGGABLE(qemu_slot4, "pcie.4");
>  ST_PLUGGABLE(qemu_slot5, "pcie.5");
> @@ -20,7 +29,7 @@ ST_PLUGGABLE(qemu_slot5, "pcie.5");
>  static const struct slot_table_entry qemu_phb_table[] = {
>  	ST_PHB_ENTRY(0, 0, qemu_slot0),
>  	ST_PHB_ENTRY(0, 1, qemu_slot1),
> -	ST_PHB_ENTRY(0, 2, qemu_slot2),
> +	ST_PHB_ENTRY(0, 2, qemu_sw_root),
>  	ST_PHB_ENTRY(0, 3, qemu_slot3),
>  	ST_PHB_ENTRY(0, 4, qemu_slot4),
>  	ST_PHB_ENTRY(0, 5, qemu_slot5),
>