From: Jason Gunthorpe <jgg@ziepe.ca>
To: Robin Murphy <robin.murphy@arm.com>
Cc: will@kernel.org, joro@8bytes.org, iommu@lists.linux.dev,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] iommu/arm-smmu-v3: Retire disable_bypass parameter
Date: Thu, 11 Apr 2024 11:26:11 -0300 [thread overview]
Message-ID: <20240411142611.GM223006@ziepe.ca> (raw)
In-Reply-To: <ea3ac4cd595a81b5511729601b2f7d4668178438.1712335927.git.robin.murphy@arm.com>
On Fri, Apr 05, 2024 at 05:52:07PM +0100, Robin Murphy wrote:
> The disable_bypass parameter has been mostly meaningless for a long time
> since the introduction of default domains. Its original intent is now
> fulfilled by the controls users have over the default domain type, and
> its remaining effect in the brief window between Stream Table
> initialisation and default domain creation hardly seems worth the
> complication. Furthermore, thanks to 2-level Stream Tables, disabling
> disable_bypass (there's another reason not to like it right there) has
> never guaranteed that any particular StreamID *will* bypass anyway - any
> device which might actually care about that wants RMRs - so there's not
> really much lost by taking away that option (which has already been
> non-default for nearing 6 years now).
>
> As part of this, also remove the weird behaviour where we "successfully"
> probe and register a non-functional SMMU if the DT "#iommu-cells"
> property is wrong. I have no memory of what possessed me to think that
> was a good idea at the time, and by now I suspect it's likely to break
> things worse than simply failing probe would.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 46 ++++++---------------
> 1 file changed, 13 insertions(+), 33 deletions(-)
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
prev parent reply other threads:[~2024-04-11 14:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-05 16:52 [PATCH] iommu/arm-smmu-v3: Retire disable_bypass parameter Robin Murphy
2024-04-09 10:19 ` Mostafa Saleh
2024-04-09 12:55 ` Will Deacon
2024-04-11 14:26 ` Jason Gunthorpe [this message]
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