linux-kernel - Re: [PATCH v1 0/4] iommu/arm-smmu-v3: Allocate vmid per vsmmu instead of s2

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: <20250305183151.GE133783@nvidia.com>
Date: Wed, 5 Mar 2025 14:31:51 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Nicolin Chen <nicolinc@...dia.com>
Cc: will@...nel.org, robin.murphy@....com, joro@...tes.org,
	linux-arm-kernel@...ts.infradead.org, iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org, shameerali.kolothum.thodi@...wei.com
Subject: Re: [PATCH v1 0/4] iommu/arm-smmu-v3: Allocate vmid per vsmmu
 instead of s2_parent

On Wed, Mar 05, 2025 at 10:23:36AM -0800, Nicolin Chen wrote:
> On Wed, Mar 05, 2025 at 12:54:52PM -0400, Jason Gunthorpe wrote:
> > On Tue, Mar 04, 2025 at 09:03:59PM -0800, Nicolin Chen wrote:
> > 
> > > Have a pair of patches getting the functions ready for the vmid migration.
> > > Decouple the vmid from S2 parent domains and move its allocation to vSMMU
> > > instances. Note that a regular S2 domain (!nest_parent) has to retain the
> > > s2_cfg and vmid for non-nesting use cases, if the SMMU HW doesn't support
> > > stage 1. Then, an S2 invalidation has to be iterated for all the vmids in
> > > the vSMMU list introduced in the S2 parent domain.
> > 
> > I was planning to also fix the S2 to be able to attach to multiple
> > IOMMU instances at the same time as getting VMID to the viommu.. It
> > doesn't quite make sense to me that viommu would allow multi-attach
> > but the normal cases wouldn't. Did you find a shortcut?
> 
> Hmm, not quite following the question. You mean vIOMMU attaching to
> multiple S2 domains?

I mean a normal S2 domain attaching to multiple devices on multiple
instances.

Jason