linux-kernel - Re: [PATCH v1 0/3] Clean-up arm-smmu-v3-sva.c: remove arm_smmu

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]

Date:   Tue, 5 Sep 2023 21:24:22 +0800
From:   Michael Shavit <mshavit@...gle.com>
To:     Jason Gunthorpe <jgg@...dia.com>
Cc:     iommu@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, will@...nel.org,
        robin.murphy@....com, nicolinc@...dia.com,
        jean-philippe@...aro.org, tina.zhang@...el.com,
        Joerg Roedel <joro@...tes.org>,
        Kevin Tian <kevin.tian@...el.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>,
        Tomas Krcka <krckatom@...zon.de>,
        Yicong Yang <yangyicong@...ilicon.com>
Subject: Re: [PATCH v1 0/3] Clean-up arm-smmu-v3-sva.c: remove arm_smmu_bond

On Tue, Sep 5, 2023 at 8:35 PM Jason Gunthorpe <jgg@...dia.com> wrote:
>
> On Tue, Sep 05, 2023 at 07:49:11PM +0800, Michael Shavit wrote:
> >
> > Note that arm-smmu-v3-sva performs a second level of normalization by
> > mapping multiple bonds (now SVA domains) attached to devices with the
> > same SMMU (if those devices have the same RID domain attached) to a
> > single arm_smmu_mmu_notifier. This is not affected by these patches.
>
> Ultimately the notifier should be per-iommu_domain as well.

Speaking of, I'm questioning whether the multi-SMMU domain patchseries
and Tina's sva domain sharing are really prerequisites to get rid of
the notifier sharing. Is anyone really depending on or taking
advantage of this? The optimization only kicks in if multiple devices
with the same SMMU, share the same RID iommu domain (although this
would be improved by fixing SVA to not depend on the RID domain) , and
are bound to common MMs.