Re: [PATCH v2 00/19] ppc/pnv: Add support for user created PHB3/PHB4 devices

["Cédric Le Goater" <clg@kaod.org>]

On 12/13/21 14:28, Cédric Le Goater wrote:
> Hello,
> 
> On the POWER8 processor, powernv8 machine, PHB3 devices can simply be
> created with :
> 
>     -device pnv-phb3,chip-id=0,index=1
> 
> with a maximum of 3 PHB3s per chip, each PHB3 adding a new PCIe bus.
> 
> On the POWER9 processor, powernv9 machine, the logic is different. The
> the chip comes with 3 PHB4 PECs (PCI Express Controller) and each PEC
> can have several PHBs :
> 
>    * PEC0 provides 1 PHB  (PHB0)
>    * PEC1 provides 2 PHBs (PHB1 and PHB2)
>    * PEC2 provides 3 PHBs (PHB3, PHB4 and PHB5)
> 
> The PEC devices can be created with :
> 
>     -device pnv-phb4-pec,chip-id=0,index=1
> 
> And the number of added PHB4 devices depends on the PEC index. Each
> PHB4 adds a new PCIe bus.
> 
> The following changes are mostly cleanups and improvements of the
> PHB3/4 realize routines to enable support. One important change is
> related to the way the powernv machine populates the device tree. It
> depends on the object hierarchy and it is necessary to reparent user
> created devices to the chip they belong to (see PATCH 5). PHB3 is a
> little more sophisticated because of its SysBusDevice nature (see
> PATCH 6).
> 
> It would be preferable for libvirt and user to add one PHB4 (one PCIe
> bus) at a time but that's another step. The plan is to merge real soon
> the first patches which are required cleanups of the models and give
> some more time for the last ones.

Applied patches 1-14 which are simple cleanups to ppc-next.

Thanks,

C.