From: Donet Tom <donettom@linux.ibm.com>
To: gbatra@linux.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org, maddy@linux.ibm.com,
Donet Tom <donettom@linux.ibm.com>
Subject: Re: [PATCH] powerpc/iommu: bypass DMA APIs for coherent allocations for pre-mapped memory
Date: Fri, 30 Jan 2026 11:16:02 +0530 [thread overview]
Message-ID: <20260130054602.21331-1-donettom@linux.ibm.com> (raw)
In-Reply-To: <20251107161105.85999-1-gbatra@linux.ibm.com>
On Fri, 07 Nov 2025 10:11:05 -0600, Gaurav Batra wrote:
> Leverage ARCH_HAS_DMA_MAP_DIRECT config option for coherent allocations as
> well. This will bypass DMA ops for memory allocations that have been
> pre-mapped.
>
> Always set device bus_dma_limit when memory is pre-mapped. In some
> architectures, like PowerPC, pmemory can be converted to regular memory via
> daxctl command. This will gate the coherent allocations to pre-mapped RAM
> only, by dma_coherent_ok().
>
> [...]
Even though this patch is now merged. But FWIW, I had verified this on my
system and it fixed the iommu_alloc failure problem for me. So
Tested-by: Donet Tom <donettom@linux.ibm.com>
--
2.52.0
prev parent reply other threads:[~2026-01-30 5:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-07 16:11 [PATCH] powerpc/iommu: bypass DMA APIs for coherent allocations for pre-mapped memory Gaurav Batra
2026-01-14 3:04 ` Madhavan Srinivasan
2026-01-30 5:46 ` Donet Tom [this message]
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