From: Jason Gunthorpe <jgg@ziepe.ca>
To: Antheas Kapenekakis <lkml@antheas.dev>
Cc: Robin Murphy <robin.murphy@arm.com>,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Vasant Hegde <vasant.hegde@amd.com>,
Alejandro Jimenez <alejandro.j.jimenez@oracle.com>,
dnaim@cachyos.org, Mario.Limonciello@amd.com
Subject: Re: [PATCH v1] iommu: Skip mapping at address 0x0 if it already exists
Date: Fri, 27 Feb 2026 10:01:57 -0400 [thread overview]
Message-ID: <20260227140157.GH44359@ziepe.ca> (raw)
In-Reply-To: <CAGwozwExiRo9RhXOHj4wLpn6Tq0N_pKwAywcr7=SwAyaaZvNZQ@mail.gmail.com>
On Fri, Feb 27, 2026 at 09:06:27AM +0100, Antheas Kapenekakis wrote:
> On Fri, 27 Feb 2026 at 02:03, Jason Gunthorpe <jgg@ziepe.ca> wrote:
> >
> > On Thu, Feb 26, 2026 at 09:40:10PM +0100, Antheas Kapenekakis wrote:
> > > I am still concerned about unaligned checks. It is a functional change
> > > that can cause regressions in all devices. The approach of this patch
> > > does not affect behavior in other devices. I would like for Jason to
> > > weigh in.
> >
> > I think Robin's solution is very clever, but I share the concern
> > regarding what all the implementations do.
>
> I will send a V3 with a ternary instead. This way, only 0 is affected.
> I will compile test now and test later today. I am impartial with either fix.
>
> ```
> phys_addr = iommu_iova_to_phys(domain, addr ? addr : 1);
> ```
Yeah, that's a good idea
Jason
prev parent reply other threads:[~2026-02-27 14:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-21 23:50 [PATCH v1] iommu: Skip mapping at address 0x0 if it already exists Antheas Kapenekakis
2026-02-23 6:02 ` Vasant Hegde
2026-02-23 7:46 ` Antheas Kapenekakis
2026-02-24 8:25 ` Vasant Hegde
2026-02-24 9:16 ` Antheas Kapenekakis
2026-02-24 19:23 ` Jason Gunthorpe
2026-02-24 19:33 ` Antheas Kapenekakis
2026-02-24 19:43 ` Jason Gunthorpe
2026-02-24 19:51 ` Antheas Kapenekakis
2026-02-25 18:27 ` Robin Murphy
2026-02-25 22:05 ` Antheas Kapenekakis
2026-02-26 19:46 ` Robin Murphy
2026-02-26 20:40 ` Antheas Kapenekakis
2026-02-27 1:03 ` Jason Gunthorpe
2026-02-27 8:06 ` Antheas Kapenekakis
2026-02-27 14:01 ` Jason Gunthorpe [this message]
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