From: Joerg Roedel <joro@8bytes.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: iommu@lists.linux-foundation.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joerg Roedel <jroedel@suse.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] iommu/of: Use device_iommu_mapped()
Date: Fri, 7 Dec 2018 10:31:58 +0100 [thread overview]
Message-ID: <20181207093158.GL16835@8bytes.org> (raw)
In-Reply-To: <42cb32df-5358-f00d-12f5-eb3135ec680a@arm.com>
On Thu, Dec 06, 2018 at 05:42:16PM +0000, Robin Murphy wrote:
> For sure - although I am now wondering whether "mapped" is perhaps a little
> ambiguous in the naming, since the answer to "can I use the API" is yes even
> when the device may currently be attached to an identity/passthrough domain
> or blocked completely, neither of which involve any "mapping". Maybe simply
> "device_has_iommu()" would convey the intent better?
The name is shorter version of:
device_is_behind_an_iommu_remapping_its_dma_transactions()
:)
The name is not perfect, but device_has_iommu() is not better because it
might be considered as a check whether the device itself has an IOMMU
built-in.
In the end an identity-mapping is also still a mapping (if the iommu
needs a page-table for that is an implementation detail), as is a
mapping with no page-table entries at all (blocking). So I think
device_iommu_mapped() is a reasonable choice.
Regards,
Joerg
next prev parent reply other threads:[~2018-12-07 9:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 17:24 [PATCH 0/5] Introduce device_iommu_maped() function Joerg Roedel
2018-12-04 17:25 ` [PATCH 1/5] driver core: Introduce device_iommu_mapped() function Joerg Roedel
2018-12-06 12:55 ` Greg Kroah-Hartman
2018-12-06 15:39 ` Joerg Roedel
2018-12-04 17:25 ` [PATCH 2/5] iommu/of: Use device_iommu_mapped() Joerg Roedel
2018-12-05 17:17 ` Robin Murphy
2018-12-06 15:35 ` Joerg Roedel
2018-12-06 17:42 ` Robin Murphy
2018-12-07 9:31 ` Joerg Roedel [this message]
2018-12-04 17:25 ` [PATCH 3/5] ACPI/IORT: " Joerg Roedel
2018-12-04 17:25 ` [PATCH 4/5] powerpc/iommu: " Joerg Roedel
2018-12-04 17:25 ` [PATCH 5/5] xhci: " Joerg Roedel
2018-12-05 17:17 ` [PATCH 0/5] Introduce device_iommu_maped() function Robin Murphy
2018-12-06 15:36 ` Joerg Roedel
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