linux-kernel - Re: PCI express switch handling ..

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 14 Mar 2010 23:32:09 -0600
From:	Grant Grundler <grundler@...isc-linux.org>
To:	Manu Abraham <abraham.manu@...il.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-pci@...r.kernel.org,
	Grant Grundler <grundler@...isc-linux.org>
Subject: Re: PCI express switch handling ..

On Sun, Mar 14, 2010 at 11:18:05PM +0400, Manu Abraham wrote:
> Hi All,
> 
> I have one of these PCIe switches on one of the PCIe cards that I have:
> 
> http://www.plxtech.com/products/expresslane/pex8604
> 
> I was wondering how to handle this thing, ie;
> 
> I have to PCIe devices behind this switch, which looks thus:
> 
> 06:00.0 PCI bridge: PLX Technology, Inc. Device 8604 (rev ba)
> 07:01.0 PCI bridge: PLX Technology, Inc. Device 8604 (rev ba)
> 07:04.0 PCI bridge: PLX Technology, Inc. Device 8604 (rev ba)
> 07:05.0 PCI bridge: PLX Technology, Inc. Device 8604 (rev ba)
> 09:00.0 Multimedia controller: Philips Semiconductors Device 7231 (rev aa)
> 0a:00.0 Multimedia controller: Philips Semiconductors Device 7231 (rev aa)

Can you post "lspci -vt" and "lspci -v" output?
It will tell us alot more about the heirarchy and address space routing.

> I am wondering if i need to access or address the switch specifically
> to forward data specifically to one of the bridges behind the switch.

No. MMIO routing is handling by MMIO "window" register in the bridge.

While it's called a "switch" because it can route MMIO transactions
from one downstream PCI-e link to any other.

> At present I can access one of the Multimedia controllers (09:00.0) ,
> but it seems I can't access the other one and hence my question as to
> determine whether it is something else.

"lspci -vt" will show what is visible in PCI Config space.

"lspci -v" will tell us how the bridge is configured.

hth,
grant
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/