linux-kernel - Re: [PATCH v2 0/5] PCI: dwc: improve msi 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]

Message-ID: <8e06a370-a37a-5f33-b43b-2830adb31b3e@nvidia.com>
Date:   Tue, 29 Sep 2020 14:22:57 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Jisheng Zhang <Jisheng.Zhang@...aptics.com>
CC:     Kishon Vijay Abraham I <kishon@...com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Richard Zhu <hongxing.zhu@....com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        "Pengutronix Kernel Team" <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        "NXP Linux Team" <linux-imx@....com>,
        Yue Wang <yue.wang@...ogic.com>,
        "Kevin Hilman" <khilman@...libre.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Jesper Nilsson <jesper.nilsson@...s.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Xiaowei Song <songxiaowei@...ilicon.com>,
        Binghui Wang <wangbinghui@...ilicon.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Stanimir Varbanov <svarbanov@...sol.com>,
        Pratyush Anand <pratyush.anand@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        <linux-omap@...r.kernel.org>, <linux-pci@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-samsung-soc@...r.kernel.org>,
        <linux-amlogic@...ts.infradead.org>, <linux-arm-kernel@...s.com>,
        <linux-arm-msm@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        Vidya Sagar <vidyas@...dia.com>
Subject: Re: [PATCH v2 0/5] PCI: dwc: improve msi handling

Hi Jisheng,

On 29/09/2020 11:48, Jisheng Zhang wrote:
> Hi Jon,
> 
> On Fri, 25 Sep 2020 09:53:45 +0100 Jon Hunter wrote:
> 
>>
>> On 24/09/2020 12:05, Jisheng Zhang wrote:
>>> Improve the msi code:
>>> 1. Add proper error handling.
>>> 2. Move dw_pcie_msi_init() from each users to designware host to solve
>>> msi page leakage in resume path.  
>>
>> Apologies if this is slightly off topic, but I have been meaning to ask
>> about MSIs and PCI. On Tegra194 which uses the DWC PCI driver, whenever we
>> hotplug CPUs we see the following warnings ...
>>
>>  [      79.068351] WARNING KERN IRQ70: set affinity failed(-22).
>>  [      79.068362] WARNING KERN IRQ71: set affinity failed(-22).
>>
> 
> I tried to reproduce this issue on Synaptics SoC, but can't reproduce it.
> Per my understanding of the code in kernel/irq/cpuhotplug.c, this warning
> happened when we migrate irqs away from the offline cpu, this implicitly
> implies that before this point the irq has bind to the offline cpu, but how
> could this happen given current dw_pci_msi_set_affinity() implementation
> always return -EINVAL

By default the smp_affinity should be set so that all CPUs can be
interrupted ...

$ cat /proc/irq/70/smp_affinity
0xff

In my case there are 8 CPUs and so 0xff implies that the interrupt can
be triggered on any of the 8 CPUs.

Do you see the set_affinity callback being called for the DWC irqchip in
migrate_one_irq()?

Cheers
Jon

-- 
nvpublic