From: Joonwon Kang <joonwonkang@google•com>
To: kevin.tian@intel•com, jgg@ziepe•ca
Cc: Alexander.Grest@microsoft•com,
alexander.shishkin@linux•intel.com, amhetre@nvidia•com,
baolu.lu@linux•intel.com, bp@alien8•de,
dave.hansen@linux•intel.com,
easwar.hariharan@linux•microsoft.com, hpa@zytor•com,
iommu@lists•linux.dev, jacob.jun.pan@linux•intel.com,
joonwonkang@google•com, joro@8bytes•org, jpb@kernel•org,
kas@kernel•org, kees@kernel•org,
linux-arm-kernel@lists•infradead.org,
linux-kernel@vger•kernel.org, mingo@redhat•com,
nicolinc@nvidia•com, peterz@infradead•org, praan@google•com,
robin.murphy@arm•com, ryasuoka@redhat•com, smostafa@google•com,
sohil.mehta@intel•com, tglx@kernel•org, will@kernel•org,
x86@kernel•org, xin@zytor•com
Subject: RE: [PATCH v2] iommu: Allow device driver to use its own PASID space for SVA
Date: Tue, 26 May 2026 12:36:06 +0000 [thread overview]
Message-ID: <20260526123606.2488278-1-joonwonkang@google.com> (raw)
In-Reply-To: <DM6PR11MB3690699A3178F1559D4BE1CA8C0B2@DM6PR11MB3690.namprd11.prod.outlook.com>
> > From: Joonwon Kang <joonwonkang@google•com>
> > Sent: Tuesday, May 26, 2026 2:58 PM
> >
> > > On Mon, May 25, 2026 at 03:29:24PM +0000, Joonwon Kang wrote:
> > >
> > > > Currently, the only known expected user of the new kAPI is our team.
> > Since
> > > > I test if the patch resolves our problem before sending it, I believe it
> > > > should be good enough. Do you mean more than our team by
> > "accompanied
> > > > users"?
> > >
> > > He means you cannot send patches like this that only serve OOT drivers
> > > to the mainline kernel.
> >
> > Hmm, it gets back to the chicken-and-egg problem. So, do you recommend
> > deferring the patch submission until we find a new in-tree user of the
> > new kAPI? I believe we will not make our module in-tree anytime soon.
> > Or, is it like I still can send the patch and get it reviewed although we
> > cannot merge it to the mainline?
> >
>
> It's not chicken-and-egg problem. Just always send them together.
>
> so let's wait until your module is ready for in-tree review...
Since adding a new kAPI has this limitation, what do you think about the
idea of adding a new boot parameter to enforce disabling ENQCMD at EL0 and
using the non-global PASID space in that case? This way, I guess we could
resolve our issue without having to wait until we have new in-tree users.
Do you think it should have the same limitation?
Thanks,
Joonwon Kang
next prev parent reply other threads:[~2026-05-26 12:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-20 15:07 [PATCH v2] iommu: Allow device driver to use its own PASID space for SVA Joonwon Kang
2026-05-21 7:39 ` Baolu Lu
2026-05-21 8:25 ` Joonwon Kang
2026-05-25 8:10 ` Tian, Kevin
2026-05-25 15:29 ` Joonwon Kang
2026-05-25 16:47 ` Jason Gunthorpe
2026-05-26 6:58 ` Joonwon Kang
2026-05-26 7:21 ` Tian, Kevin
2026-05-26 8:44 ` Joonwon Kang
2026-05-26 12:36 ` Joonwon Kang [this message]
2026-05-26 12:39 ` Jason Gunthorpe
2026-05-26 12:46 ` Joonwon Kang
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