From: Jason Gunthorpe <jgg@ziepe.ca>
To: Vijayanand Jitta <vijayanand.jitta@oss.qualcomm.com>
Cc: Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
"Joerg Roedel (AMD)" <joro@8bytes.org>,
linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org,
Prakash Gupta <prakash.gupta@oss.qualcomm.com>
Subject: Re: [PATCH v5] iommu/io-pgtable-arm: Add support for contiguous hint bit
Date: Wed, 23 Sep 2026 21:15:02 -0300 [thread overview]
Message-ID: <20260924001502.GO1540250@ziepe.ca> (raw)
In-Reply-To: <20260921-iommu_contig_hint-v5-1-e7fbd1c3774d@oss.qualcomm.com>
On Mon, Sep 21, 2026 at 04:44:07PM +0530, Vijayanand Jitta wrote:
> From: Prakash Gupta <prakash.gupta@oss.qualcomm.com>
>
> Add support for the contiguous hint (CONT) bit in ARM LPAE page tables.
> When a set of consecutive PTEs map a naturally aligned contiguous block of
> memory, set CONT on every descriptor in that group so the hardware can
> combine translations and improve TLB reach.
>
> Advertise the supported CONT group sizes in pgsize_bitmap. Callers select
> those sizes through the normal page-size selection path; io-pgtable-arm
> then installs the corresponding tagged descriptors directly. A partial
> unmap of a tagged CONT group is rejected before modifying any descriptor,
> so a rejected request cannot leave the group partly unmapped.
>
> The IO_PGTABLE_QUIRK_ARM_NO_CONT_HINT quirk allows SMMU drivers to disable
> CONT support for hardware with implementation-specific errata.
smmuv3 has this errata, it must be disabled there too. I didn't notice
it in this patch?
Jason
next prev parent reply other threads:[~2026-09-24 0:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-21 11:14 Vijayanand Jitta
2026-09-24 0:15 ` Jason Gunthorpe [this message]
2026-09-24 18:49 ` Daniel Mentz
2026-09-24 22:53 ` Jason Gunthorpe
2026-09-24 20:36 ` Daniel Mentz
2026-09-24 22:55 ` Jason Gunthorpe
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