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From: Zihan Yang <whois.zihan.yang@gmail.com>
To: linux-pci@vger.kernel.org
Subject: Peer bridge fixup issue under multiple pci domain
Date: Sat, 25 Aug 2018 22:58:57 +0800	[thread overview]
Message-ID: <CAKwiv-gK1wxw57TVK7GXe3bfkr=0eCS9zn7F_mZRYUL+2Ovr9w@mail.gmail.com> (raw)

Hi all,

I'm trying to use multiple pci domain in qemu q35, but I find there
might be some issues in peer bridge fixup.

In short, pcibios_fixup_peer_bridges function assumes only one pci
domain (0) by default. This is OK when as qemu by default uses only
one pci domain too. However, if I add another host bridge which is
put into pci domain 1 by using _SEG, and a pcie_pci_bridge is attached
to the bus 1 under this new pci domain 1 rather than domain 0, the
kernel will recognize the bus 01 differently.

More specifically, pcibios_fixup_peer_bridges only reads all the buses
under domain 0 but it can read the pci bus 01 in pci domain 1 and treat
it as a peer bus of 0000:00. The consequence is this 01 bus is recognized
as 0000:01, but it should have been recognized as 0001:01.

The host bus 0001:00 can be recognized so I guess pcibios_fixup_peer_bridges
needs updating to take care of multiple domains? Or is it just an bios issue?
I'm not quite sure and I'm open to any suggestions.

Thanks,
Ziahn

             reply	other threads:[~2018-08-25 18:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-25 14:58 Zihan Yang [this message]
2018-08-28 19:35 ` Peer bridge fixup issue under multiple pci domain Bjorn Helgaas
2018-09-03  1:51   ` Zihan Yang
2018-09-03  1:51     ` Zihan Yang

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