From: Joerg Roedel <joro@8bytes.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: iommu@lists.linux-foundation.org, Vincent.Wan@amd.com,
Joerg Roedel <jroedel@suse.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 07/20] iommu/amd: Remove special mapping code for dma_ops path
Date: Tue, 12 Jul 2016 13:08:39 +0200 [thread overview]
Message-ID: <20160712110839.GF12639@8bytes.org> (raw)
In-Reply-To: <5784CCAB.8000007@arm.com>
Hi Robin,
On Tue, Jul 12, 2016 at 11:55:39AM +0100, Robin Murphy wrote:
> > start = address;
> > for (i = 0; i < pages; ++i) {
> > - ret = dma_ops_domain_map(dma_dom, start, paddr, dir);
> > - if (ret == DMA_ERROR_CODE)
> > + ret = iommu_map_page(&dma_dom->domain, start, paddr,
> > + PAGE_SIZE, prot, GFP_ATOMIC);
>
> I see that amd_iommu_map/unmap() takes a lock around calling
> iommu_map/unmap_page(), but we don't appear to do that here. That seems
> to suggest that either one is unsafe or the other is unnecessary.
At this point no locking is required, because in this code path we know
that we own the memory range and that nobody else is mapping that range.
In the IOMMU-API path we can't make that assumption, so locking is
required there. Both code-path use different types of domains, so there
is also no chance that a domain is used in both code-paths (except when
a dma-ops domain is set up).
Joerg
next prev parent reply other threads:[~2016-07-12 11:08 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 11:44 [PATCH 00/20] iommu/amd: Use generic IOVA allocator Joerg Roedel
2016-07-08 11:44 ` [PATCH 06/20] iommu/amd: Pass gfp-flags to iommu_map_page() Joerg Roedel
[not found] ` <1467978311-28322-1-git-send-email-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-07-08 11:44 ` [PATCH 01/20] iommu: Add apply_dm_region call-back to iommu-ops Joerg Roedel
2016-07-08 11:44 ` [PATCH 02/20] iommu/amd: Select IOMMU_IOVA for AMD IOMMU Joerg Roedel
2016-07-08 11:44 ` [PATCH 03/20] iommu/amd: Allocate iova_domain for dma_ops_domain Joerg Roedel
2016-07-08 11:44 ` [PATCH 04/20] iommu/amd: Create a list of reserved iova addresses Joerg Roedel
2016-07-08 11:44 ` [PATCH 05/20] iommu/amd: Implement apply_dm_region call-back Joerg Roedel
2016-07-08 11:44 ` [PATCH 07/20] iommu/amd: Remove special mapping code for dma_ops path Joerg Roedel
[not found] ` <1467978311-28322-8-git-send-email-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-07-12 10:55 ` Robin Murphy
2016-07-12 11:08 ` Joerg Roedel [this message]
2016-07-12 11:42 ` Robin Murphy
[not found] ` <5784D7C3.4010104-5wv7dgnIgG8@public.gmane.org>
2016-07-12 11:48 ` Joerg Roedel
2016-07-08 11:44 ` [PATCH 08/20] iommu/amd: Make use of the generic IOVA allocator Joerg Roedel
2016-07-08 11:45 ` [PATCH 09/20] iommu/amd: Remove other remains of old address allocator Joerg Roedel
2016-07-08 11:45 ` [PATCH 10/20] iommu/amd: Remove align-parameter from __map_single() Joerg Roedel
2016-07-08 11:45 ` [PATCH 11/20] iommu/amd: Set up data structures for flush queue Joerg Roedel
2016-07-08 11:45 ` [PATCH 12/20] iommu/amd: Allow NULL pointer parameter for domain_flush_complete() Joerg Roedel
2016-07-08 11:45 ` [PATCH 13/20] iommu/amd: Implement flush queue Joerg Roedel
2016-07-08 11:45 ` [PATCH 14/20] iommu/amd: Implement timeout to flush unmap queues Joerg Roedel
2016-07-08 11:45 ` [PATCH 15/20] iommu/amd: Introduce dir2prot() helper Joerg Roedel
2016-07-08 11:45 ` [PATCH 17/20] iommu/amd: Use dev_data->domain in get_domain() Joerg Roedel
2016-07-08 11:45 ` [PATCH 16/20] iommu/amd: Optimize map_sg and unmap_sg Joerg Roedel
2016-07-12 11:33 ` Robin Murphy
[not found] ` <5784D597.4010703-5wv7dgnIgG8@public.gmane.org>
2016-07-12 13:30 ` [PATCH 16/20 v2] " Joerg Roedel
2016-07-12 15:34 ` Robin Murphy
[not found] ` <57850DF8.9040507-5wv7dgnIgG8@public.gmane.org>
2016-07-13 10:27 ` Joerg Roedel
2016-07-08 11:45 ` [PATCH 18/20] iommu/amd: Handle IOMMU_DOMAIN_DMA in ops->domain_free call-back Joerg Roedel
2016-07-08 11:45 ` [PATCH 19/20] iommu/amd: Flush iova queue before releasing dma_ops_domain Joerg Roedel
2016-07-08 11:45 ` [PATCH 20/20] iommu/amd: Use container_of to get dma_ops_domain Joerg Roedel
2016-07-12 9:03 ` [PATCH 00/20] iommu/amd: Use generic IOVA allocator Wan Zongshun
2016-07-12 10:55 ` Joerg Roedel
[not found] ` <20160712105533.GE12639-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-07-13 9:44 ` Wan Zongshun
[not found] ` <57860D78.5090409-6ukY98dZOFrYtjvyW6yDsg@public.gmane.org>
2016-07-13 9:51 ` Joerg Roedel
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