linux-kernel - Re: PCIe MSI address is not written at pci_enable_msi

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]

Message-ID: <5783733C.70702@arm.com>
Date:	Mon, 11 Jul 2016 11:21:48 +0100
From:	Marc Zyngier <marc.zyngier@....com>
To:	Bharat Kumar Gogada <bharat.kumar.gogada@...inx.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:	Arnd Bergmann <arnd@...db.de>, Bjorn Helgaas <bhelgaas@...gle.com>,
	nofooter <nofooter@...inx.com>
Subject: Re: PCIe MSI address is not written at pci_enable_msi_range call

[Please don't top-post]

On 11/07/16 10:33, Bharat Kumar Gogada wrote:
> Hi Marc,
> 
> Thanks for the reply.
> 
> From PCIe Spec:
> MSI Enable Bit:
> If 1 and the MSI-X Enable bit in the MSI-X Message
> Control register (see Section 6.8.2.3) is 0, the
> function is permitted to use MSI to request service
> and is prohibited from using its INTx# pin.
> 
> From Endpoint perspective, MSI Enable = 1 indicates MSI can be used which means MSI address and data fields are available/programmed.
> 
> In our SoC whenever MSI Enable goes from 0 --> 1 the hardware latches onto MSI address and MSI data values.
> 
> With current MSI implementation in kernel, our SoC is latching on to incorrect address and data values, as address/data
> are updated much later than MSI Enable bit.

Interesting. It looks like we're doing something wrong in the MSI flow.
Can you confirm that this is limited to MSI and doesn't affect MSI-X?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...