From: Christoph Hellwig <hch@infradead.org>
To: Julien Grall <julien.grall@arm.com>
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
iommu@lists.linux-foundation.org, leo.yan@linaro.org,
xen-devel <xen-devel@lists.xenproject.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
m.szyprowski@samsung.com
Subject: Re: Fail to boot Dom0 on Xen Arm64 after "dma-mapping: bypass indirect calls for dma-direct"
Date: Thu, 17 Jan 2019 06:11:58 -0800 [thread overview]
Message-ID: <20190117141157.GA5184@infradead.org> (raw)
In-Reply-To: <1855c743-becd-fd52-50b9-86398f6cb985@arm.com>
On Thu, Jan 17, 2019 at 11:43:49AM +0000, Julien Grall wrote:
> Looking at the change for arm64, you will always call dma-direct API. In
> previous Linux version, xen-swiotlb will call dev->archdata.dev_dma_ops (a
> copy of dev->dma_ops before setting Xen DMA ops) if not NULL. Does it mean
> we expect dev->dma_ops to always be NULL and hence using dma-direct API?
The way I understood the code from inspecting it and sking the
maintainers a few askings is that for DOM0 we always use xen-swiotlb
as the actual dma_map_ops, but then use the functions in page-coherent.h
only to deal with cache maintainance, so it should be safe.
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next prev parent reply other threads:[~2019-01-17 14:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 17:25 Fail to boot Dom0 on Xen Arm64 after "dma-mapping: bypass indirect calls for dma-direct" Julien Grall
2019-01-16 18:19 ` Christoph Hellwig
2019-01-17 11:43 ` Julien Grall
2019-01-17 14:11 ` Christoph Hellwig [this message]
[not found] ` <20190117141157.GA5184-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2019-01-19 0:43 ` Stefano Stabellini
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