Messages in this thread | | | Date | Tue, 27 Sep 2022 16:50:03 +0100 | Subject | Re: [PATCH] iommu/io-pgtable: Make IOMMU_IO_PGTABLE_DART invisible | From | Robin Murphy <> |
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On 2022-09-27 16:29, Geert Uytterhoeven wrote: > Hi Robin, > > On Tue, Sep 27, 2022 at 5:09 PM Robin Murphy <robin.murphy@arm.com> wrote: >> On 2022-09-27 15:48, Geert Uytterhoeven wrote: >>> On Tue, Sep 27, 2022 at 4:15 PM Robin Murphy <robin.murphy@arm.com> wrote: >>>> On 2022-09-27 14:36, Geert Uytterhoeven wrote: >>>>> There is no point in asking the user about both "Apple DART Formats" and >>>>> "Apple DART IOMMU Support", as the former is useless without the latter, >>>>> and the latter auto-selects the former. >>>>> >>>>> Fixes: 745ef1092bcfcf3b ("iommu/io-pgtable: Move Apple DART support to its own file") >>>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >>>>> --- >>>>> Should IOMMU_IO_PGTABLE_LPAE and IOMMU_IO_PGTABLE_ARMV7S be made >>>>> invisible, too? >>>>> Are there users that do not select them? >>>> >>>> The aim was for formats to be independently selectable for COMPILE_TEST >>>> coverage. The Arm formats are manually selectable for the sake of their >>>> runtime self-tests, which are self-contained, but since DART format >>>> doesn't do anything by itself I'd agree there's no need to prompt when >>>> !COMPILE_TEST here. >>> >>> IOMMU_IO_PGTABLE_LPAE and IOMMU_IO_PGTABLE_ARMV7S are >>> selected by other symbols that can be enabled when compile-testing, so >>> the tests can still be enabled in those cases, too >> >> Sure, but when you want to compile-test a thing, what would you rather >> do: enable the thing, or go hunting to find some other thing that >> happens to select the thing you actually want, then potentially have to >> figure out *that* thing's dependencies, and so on? > > Agreed. > >> Coverage isn't solely about whether it's technically possible to ever >> reach somewhere at all, it's just as much about how easily and/or often >> you can get there in practice. I don't see who benefits from making >> COMPILE_TEST harder to use :/ > > So perhaps the visibility of IOMMU_IO_PGTABLE_LPAE and > IOMMU_IO_PGTABLE_ARMV7S should depend on COMPILE_TEST? > Normal users would still get it through select when needed.
As I say those still offer functionality beyond compile-testing, but now you've got me suspecting that it's already suboptimal that one has to enable the format to make the self-test option appear... Perhaps what we want is a separate master option to enable io-pgtable self-tests in general, then rejig the rest around that.
Of course the self-tests would be even more useful if the harness was at the level of the core io-pgtable API so it could cover new formats automatically as long as they provide the configuration parameters, but that's a separate matter for someone with sufficient free time and enthusiasm :)
Cheers, Robin.
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