linux-kernel - Re: [PATCH v2 4/5] iommu: Support mm PASID 1:n with sva domains

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: <ZO+oRPOf9jyNG2+B@ziepe.ca>
Date:   Wed, 30 Aug 2023 17:36:20 -0300
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Vasant Hegde <vasant.hegde@....com>
Cc:     Tina Zhang <tina.zhang@...el.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Michael Shavit <mshavit@...gle.com>, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/5] iommu: Support mm PASID 1:n with sva domains

On Mon, Aug 28, 2023 at 02:02:52PM +0530, Vasant Hegde wrote:

> I am not sure whether I understood the flow completely. Just wondering why you
> are not freeing pasid in iommu_sva_unbind_device().
> I mean once iommu_mm->sva_domains becomes free shouldn't we free the
> iommu_mm->pasid?

No, for Intel use cases that PASID permanently becomes part of the
ENQCMD MSR and cannot be revoked once it has been set
 
> Also in this function (mm_pasid_drop()), should we check/free sva domains?

No, the driver must support a SVA domain with an empty mm_struct, eg
by hooking release.

Jason