From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org
Cc: Oliver O'Halloran <oohall@gmail.com>,
Cédric Le Goater <clg@kaod.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH kernel] powerpc/dma: Fix dma_map_ops::get_required_mask
Date: Thu, 10 Sep 2020 22:55:32 +1000 (AEST) [thread overview]
Message-ID: <159974250724.1017939.2306300501613089726.b4-ty@ellerman.id.au> (raw)
In-Reply-To: <20200908015106.79661-1-aik@ozlabs.ru>
On Tue, 8 Sep 2020 11:51:06 +1000, Alexey Kardashevskiy wrote:
> There are 2 problems with it:
> 1. "<" vs expected "<<"
> 2. the shift number is an IOMMU page number mask, not an address mask
> as the IOMMU page shift is missing.
>
> This did not hit us before f1565c24b596 ("powerpc: use the generic
> dma_ops_bypass mode") because we had there additional code to handle
> bypass mask so this chunk (almost?) never executed. However there
> were reports that aacraid does not work with "iommu=nobypass".
> After f1565c24b596, aacraid (and probably others which call
> dma_get_required_mask() before setting the mask) was unable to
> enable 64bit DMA and fall back to using IOMMU which was known not to work,
> one of the problems is double free of an IOMMU page.
>
> [...]
Applied to powerpc/fixes.
[1/1] powerpc/dma: Fix dma_map_ops::get_required_mask
https://git.kernel.org/powerpc/c/437ef802e0adc9f162a95213a3488e8646e5fc03
cheers
prev parent reply other threads:[~2020-09-10 13:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 1:51 [PATCH kernel] powerpc/dma: Fix dma_map_ops::get_required_mask Alexey Kardashevskiy
2020-09-08 5:44 ` Christoph Hellwig
2020-09-08 12:06 ` Alexey Kardashevskiy
2020-09-08 12:19 ` Christoph Hellwig
[not found] ` <1746dd66810.27bb.1ca38dd7e845b990cd13d431eb58563d@ozlabs.ru>
[not found] ` <20200909075849.GA12282@lst.de>
2020-09-09 9:36 ` Alexey Kardashevskiy
2020-09-15 6:50 ` Christoph Hellwig
2020-09-22 2:26 ` Alexey Kardashevskiy
2020-09-23 14:10 ` Christoph Hellwig
2020-09-24 7:03 ` Alexey Kardashevskiy
2020-09-25 4:56 ` Christoph Hellwig
2021-09-29 8:48 ` Alexey Kardashevskiy
2020-09-08 6:45 ` Michael Ellerman
2020-09-08 11:45 ` Cédric Le Goater
2020-09-10 12:55 ` Michael Ellerman [this message]
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