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Subject: Re: [edk2-devel] [PATCH v2 0/4] Add extra pci roots support for Arm
To: <devel@edk2.groups.io>, <lersek@redhat.com>, Ard Biesheuvel
	<ard.biesheuvel@arm.com>
CC: <jordan.l.justen@intel.com>, <leif@nuviainc.com>, <xieyingtai@huawei.com>,
	<miaoyubo@huawei.com>
References: <20201109130511.5946-1-cenjiahui@huawei.com>
 <bb4c43a9-455d-aaba-37f4-a6874eb5ac51@arm.com>
 <286c4d14-82f4-6238-2fb1-15e6072fad07@redhat.com>
From: "Jiahui Cen" <cenjiahui@huawei.com>
Message-ID: <0575acab-fb25-9805-8735-f85f57d8764a@huawei.com>
Date: Mon, 16 Nov 2020 09:33:21 +0800
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On 2020/11/14 3:44, Laszlo Ersek wrote:
> On 11/12/20 09:49, Ard Biesheuvel wrote:
>> On 11/9/20 2:05 PM, Jiahui Cen wrote:
>>> Changes with v1
>>> v1->v2:
>>> Separated into four patches.
>>> Factor the same logic parts into a new library.
>>>
>>> v1: https://edk2.groups.io/g/devel/topic/72723351#56901
>>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3059
>>> QEMU:
>>> https://lore.kernel.org/qemu-devel/20201103120157.2286-1-cenjiahui@huawei.com/
>>>
>>>
>>> This patch series adds support for extra pci roots for ARM.
>>>
>>
>> Why?
> 
> I don't know Jiahui Cen's particular reasons; on x86, pxb-pcie is useful
> for associating PCIe hierarchies with particular NUMA nodes. See
> "docs/pci_expander_bridge.txt" in the QEMU tree.
> 
> Also, in Jiahui Cen's QEMU blurb linked above, the following is included:
> 
>> Currently pxb-pcie is not supported by arm,
>> the reason for it is pxb-pcie is not described in DSDT table
>> and only one main host bridge is described in acpi tables,
>> which means it is not impossible to present different io numas
>> for different devices.
> 
> So I guess this work aims to extend the same PCI(e)<->NUMA association
> feature, from x86 to ARM.
> > Thanks,
> Laszlo
> 
> 
> .
> 

Right, we'd like to extend the pxb-pcie feature on ARM so that PCI(e)
can be associated with particular NUMA nodes.

Thanks,
Jiahui