linux-kernel - Re: [PATCH v4 18/23] iommu/arm-smmu-v3-iommufd: Support implementation-defined hw

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: <aCY+rXsygxjHYRhK@Asurada-Nvidia>
Date: Thu, 15 May 2025 12:21:17 -0700
From: Nicolin Chen <nicolinc@...dia.com>
To: Jason Gunthorpe <jgg@...dia.com>
CC: <kevin.tian@...el.com>, <corbet@....net>, <will@...nel.org>,
	<bagasdotme@...il.com>, <robin.murphy@....com>, <joro@...tes.org>,
	<thierry.reding@...il.com>, <vdumpa@...dia.com>, <jonathanh@...dia.com>,
	<shuah@...nel.org>, <jsnitsel@...hat.com>, <nathan@...nel.org>,
	<peterz@...radead.org>, <yi.l.liu@...el.com>, <mshavit@...gle.com>,
	<praan@...gle.com>, <zhangzekun11@...wei.com>, <iommu@...ts.linux.dev>,
	<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-tegra@...r.kernel.org>,
	<linux-kselftest@...r.kernel.org>, <patches@...ts.linux.dev>,
	<mochs@...dia.com>, <alok.a.tiwari@...cle.com>, <vasant.hegde@....com>
Subject: Re: [PATCH v4 18/23] iommu/arm-smmu-v3-iommufd: Support
 implementation-defined hw_info

On Thu, May 15, 2025 at 03:56:29PM -0300, Jason Gunthorpe wrote:
> On Thu, May 15, 2025 at 11:52:05AM -0700, Nicolin Chen wrote:
> > On Thu, May 15, 2025 at 02:17:06PM -0300, Jason Gunthorpe wrote:
> > > On Thu, May 08, 2025 at 08:02:39PM -0700, Nicolin Chen wrote:
> > Should the first call return out_data_type=CMDQV while returning
> > the arm_smmu_v3 hw_info data? Otherwise, VMM wouldn't know what
> > to set in the input sub_data_type of the 2nd ioctl?
> 
> No, either set a flag in the smmu_v3 hw_info, as you were doing here,
> or just have the vmm probe it. Given the VMM is likely to be told to
> run in vCMDQ mode on the command line try-and-fail doesn't sound so
> bad.
> 
> And I guess we don't need a "sub type" just a "requested type" where 0
> means return the best one and non-zero means return a specific one or
> fail with EOPNOTSUPP.

OK. I think this would work:
hw_info (req_type=0)     => out_data_type=SMMU_V3, flags=HAS_CMDQV
hw_info (req_type=CMDQV) => out_data_type=CMDQV,   flags=0

Or, would it be simpler by having a sub_data_uptr:
hw_info => out_data_type=SMMU_V3, sub_data_type=CMDQV,
           data_uptr=iommu_hw_info_arm_smmuv3,
	   sub_data_uptr=iommu_hw_info_tegra241_cmdqv
?

Thanks
Nicolin