Messages in this thread | | | Date | Wed, 30 Nov 2022 09:28:47 +0800 | Subject | Re: [PATCH v2 4/7] iommu: Let iommu.strict override ops->def_domain_type | From | Baolu Lu <> |
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On 2022/11/30 4:09, Jason Gunthorpe wrote: > On Tue, Nov 29, 2022 at 06:41:22PM +0000, Robin Murphy wrote: >> On 2022-11-29 17:33, Jason Gunthorpe wrote: >>> On Mon, Nov 28, 2022 at 09:01:43PM +0000, Robin Murphy wrote: >>> >>>> I'm hardly an advocate for trying to save users from themselves, but I >>>> honestly can't see any justifiable reason for not having sysfs respect >>>> iommu_get_def_domain_type(). >>> >>> We really need to rename this value if it is not actually just an >>> advisory "default" but a functional requirement .. >> >> It represents a required default domain type. As in, the type for the >> device's default domain. Not the default type for a domain. It's the >> iommu_def_domain_type variable that holds the *default* default domain type >> ;) > > I find the name "default domain" incredibly confusing at this point in > time. > > I would like to call that the "dma-api domain" - its primary purpose > is to be the domain that the DMA API uses to operate the IOMMU, there > is little "default" about it. This meshes better with our apis talking > about ownership and so forth. > > So, if the op was called > get_dma_api_domain_type() > > It is pretty clear that it is the exact type of domain that should be > created to support the DMA API, which is what I think you have been > describing it is supposed to do? > > And with Lu's series we have the set_platform_dma() (Lu perhaps you > should call this set_platform_dma_api() to re-enforce it is about the > DMA API, not some nebulous DMA thing)
Sure thing. It's more specific.
> > Which is basically the other way to configure the DMA API for > operation. > > And encapsulating more of the logic to setup and manage the DMA API's > domain into dma-iommu.c would also be helpful to understanding. > >> Which reminds me I should finish that patch undoing my terrible >> ops->default_domain_ops idea, not least because they are misleadingly >> unrelated to default domains... > > :) > >>> It is close to being clear, once we get the last touches of dma-iommu >>> stuff out of the drivers it should be quite clear >> >> Cool, some upheaval of .domain_alloc is next on my hitlist anyway, so that >> might be a good excuse to upheave it a bit more and streamline the type >> stuff along the way. > > Yes, I think so. I want to tidy things a bit so adding this "user > space" domain concept is a little nicer > > Jason >
-- Best regards, baolu
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