linux-kernel - Re: [PATCH v2] iommu/vt-d: Make DMAR_UNITS

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:   Wed, 18 May 2022 14:58:23 -0500
From:   Steve Wahl <steve.wahl@....com>
To:     Baolu Lu <baolu.lu@...ux.intel.com>
Cc:     Steve Wahl <steve.wahl@....com>, Joerg Roedel <jroedel@...e.de>,
        David Woodhouse <dwmw2@...radead.org>,
        Will Deacon <will@...nel.org>,
        iommu@...ts.linux-foundation.org,
        Mike Travis <mike.travis@....com>,
        Dimitri Sivanich <sivanich@....com>,
        Russ Anderson <russ.anderson@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] iommu/vt-d: Make DMAR_UNITS_SUPPORTED a config setting

On Fri, May 13, 2022 at 10:09:46AM +0800, Baolu Lu wrote:
> On 2022/5/13 07:12, Steve Wahl wrote:
> > On Thu, May 12, 2022 at 10:13:09AM -0500, Steve Wahl wrote:
> > > To support up to 64 sockets with 10 DMAR units each (640), make the
> > > value of DMAR_UNITS_SUPPORTED adjustable by a config variable,
> > > CONFIG_DMAR_UNITS_SUPPORTED, and make it's default 1024 when MAXSMP is
> > > set.
> > > 
> > > If the available hardware exceeds DMAR_UNITS_SUPPORTED (previously set
> > > to MAX_IO_APICS, or 128), it causes these messages: "DMAR: Failed to
> > > allocate seq_id", "DMAR: Parse DMAR table failure.", and "x2apic: IRQ
> > > remapping doesn't support X2APIC mode x2apic disabled"; and the system
> > > fails to boot properly.
> > > 
> > > Signed-off-by: Steve Wahl <steve.wahl@....com>
> > 
> > I've received a report from the kernel test robot <lkp@...el.com>,
> > that this patch causes an error (shown below) when
> > CONFIG_IOMMU_SUPPORT is not set.
> > 
> > In my opinion, this is because include/linux/dmar.h and
> > include/linux/intel-iommu are being #included when they are not really
> > being used.
> > 
> > I've tried placing the contents of intel-iommu.h within an #ifdef
> > CONFIG_INTEL_IOMMU, and that fixes the problem.
> > 
> > Two questions:
> > 
> > A) Is this the desired approach to to the fix?
> 
> Most part of include/linux/intel-iommu.h is private to Intel IOMMU
> driver. They should be put in a header like drivers/iommu/intel
> /iommu.h. Eventually, we should remove include/linux/intel-iommu.h
> and device drivers interact with iommu subsystem through the IOMMU
> kAPIs.
> 
> Best regards,
> baolu

Baolu's recent patch to move intel-iommu.h private still allows my
[PATCH v2] to apply with no changes, and gets rid of the compile
errors when CONFIG_IOMMU_SUPPORT is not set, so the kernel test robot
should be happy now.

Is there another step I should do to bring this patch back into focus?

Thanks.

--> Steve

-- 
Steve Wahl, Hewlett Packard Enterprise