linux-kernel - Re: [PATCH v6 1/5] iommu: Return -EMEDIUMTYPE for incompatible domain and device/group

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: <Yx0fVJpaojM5RNR4@Asurada-Nvidia>
Date:   Sat, 10 Sep 2022 16:35:48 -0700
From:   Nicolin Chen <nicolinc@...dia.com>
To:     Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Jason Gunthorpe <jgg@...dia.com>
CC:     "will@...nel.org" <will@...nel.org>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>,
        "marcan@...can.st" <marcan@...can.st>,
        "sven@...npeter.dev" <sven@...npeter.dev>,
        "alyssa@...enzweig.io" <alyssa@...enzweig.io>,
        "robdclark@...il.com" <robdclark@...il.com>,
        "dwmw2@...radead.org" <dwmw2@...radead.org>,
        "baolu.lu@...ux.intel.com" <baolu.lu@...ux.intel.com>,
        "mjrosato@...ux.ibm.com" <mjrosato@...ux.ibm.com>,
        "gerald.schaefer@...ux.ibm.com" <gerald.schaefer@...ux.ibm.com>,
        "orsonzhai@...il.com" <orsonzhai@...il.com>,
        "baolin.wang@...ux.alibaba.com" <baolin.wang@...ux.alibaba.com>,
        "zhang.lyra@...il.com" <zhang.lyra@...il.com>,
        "thierry.reding@...il.com" <thierry.reding@...il.com>,
        "vdumpa@...dia.com" <vdumpa@...dia.com>,
        "jonathanh@...dia.com" <jonathanh@...dia.com>,
        "jean-philippe@...aro.org" <jean-philippe@...aro.org>,
        "cohuck@...hat.com" <cohuck@...hat.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "shameerali.kolothum.thodi@...wei.com" 
        <shameerali.kolothum.thodi@...wei.com>,
        "thunder.leizhen@...wei.com" <thunder.leizhen@...wei.com>,
        "christophe.jaillet@...adoo.fr" <christophe.jaillet@...adoo.fr>,
        "yangyingliang@...wei.com" <yangyingliang@...wei.com>,
        "jon@...id-run.com" <jon@...id-run.com>,
        "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "asahi@...ts.linux.dev" <asahi@...ts.linux.dev>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
        "linux-s390@...r.kernel.org" <linux-s390@...r.kernel.org>,
        "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
        "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>
Subject: Re: [PATCH v6 1/5] iommu: Return -EMEDIUMTYPE for incompatible
 domain and device/group

On Thu, Sep 08, 2022 at 09:08:38AM -0300, Jason Gunthorpe wrote:
> On Thu, Sep 08, 2022 at 09:30:57AM +0000, Tian, Kevin wrote:

> > There are also cases where common kAPIs are called in the attach
> > path which may return -EINVAL and random errno, e.g.:
> > 
> > omap_iommu_attach_dev()
> >   omap_iommu_attach()
> >     iommu_enable()
> >       pm_runtime_get_sync()
> >         __pm_runtime_resume()
> >           rpm_resume()
> > 	if (dev->power.runtime_error) {
> > 		retval = -EINVAL;
 
> Yes, this is was also on my mind with choosing an unpopular return
> code, it has a higher chance of not coming out of some other kernel
> API

I wonder if it would be safe to just treat a pm_runtime_get_sync()
failure as -ENODEV, since a PM resume() mostly occurs to the IOMMU
that an IOMMU client/master device is behind, while an iommu_domain
rarely intervenes.