linux-kernel - Re: [RFC 09/13] iommu/smmuv3: Get prepared for nested stage support

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: <012d4950-7a06-2d59-85a0-44d511ad893b@redhat.com>
Date:   Fri, 31 Aug 2018 16:11:37 +0200
From:   Auger Eric <eric.auger@...hat.com>
To:     Jean-Philippe Brucker <jean-philippe.brucker@....com>,
        "\"eric.auger.pro"@gmail.com, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        kvmarm@...ts.cs.columbia.edu, joro@...tes.org,
        alex.williamson@...hat.com, jacob.jun.pan@...ux.intel.com,
        "yi.l.liu\""@linux.intel.com, will.deacon@....com,
        robin.murphy@....com
Cc:     marc.zyngier@....com, peter.maydell@...aro.org,
        christoffer.dall@....com
Subject: Re: [RFC 09/13] iommu/smmuv3: Get prepared for nested stage support

Hi Jean-Philippe,

On 08/31/2018 03:20 PM, Jean-Philippe Brucker wrote:
> On 23/08/18 13:17, Eric Auger wrote:
>>  	if (ste->s1_cfg) {
>> -		BUG_ON(ste_live);
> 
> Scary! :) The current code assumes that it can make modifications to the
> STE in any order and enable translation after a sync. So far I haven't
> been able to find anything that violates this rule in the spec: "If
> software modifies the structure while it is valid, it must not allow the
> structure to enter an invalid intermediate state." So maybe it's fine,
> though to be safe I would have started with disabling the STE
> (http://www.linux-arm.org/git?p=linux-jpb.git;a=commitdiff;h=936e49f923e101c061269eadd5fa43fef819d2e9)

Yep this works with my setup but I was waiting for such kind of comments
to turn this prototype into something more "production level" ;-) Did
you send anything upstream, related to this branch?

Thanks

Eric
> 
> Thanks,
> Jean
>