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Groups > linux.kernel > #1519845
| From | Joerg Roedel <joro@8bytes.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback |
| Date | 2016-11-11 16:10 +0100 |
| Message-ID | <sClCO-5Wb-9@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <szKR3-112-23@gated-at.bofh.it> <sBZLY-871-27@gated-at.bofh.it> <sC05k-8tv-17@gated-at.bofh.it> <sC0f0-77-9@gated-at.bofh.it> <sCl9M-5wV-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Nov 11, 2016 at 02:34:39PM +0000, Robin Murphy wrote:
> On 10/11/16 16:16, Joerg Roedel wrote:
> > On Thu, Nov 10, 2016 at 04:07:08PM +0000, Robin Murphy wrote:
> >> On 10/11/16 15:46, Joerg Roedel wrote:
> >>> On Fri, Nov 04, 2016 at 11:24:06AM +0000, Eric Auger wrote:
> >>>> + resource_list_for_each_entry(window, &bridge->windows) {
> >>>> + if (resource_type(window->res) != IORESOURCE_MEM &&
> >>>> + resource_type(window->res) != IORESOURCE_IO)
> >>>> + continue;
> >>>
> >>> Why do you care about IO resources?
> >>
> >> [since this is essentially code I wrote]
> >>
> >> Because they occupy some area of the PCI address space, therefore I
> >> assumed that, like memory windows, they would be treated as P2P. Is that
> >> not the case?
> >
> > No, not at all. The IO-space is completly seperate from the MEM-space.
> > They are two different address-spaces, addressing different things. And
> > the IO-space is also not translated by any IOMMU I am aware of.
>
> OK. On the particular root complex I have to hand, though, any DMA to
> IOVAs between 0x5f800000 and 0x5fffffff sends an error back to the
> endpoint, and that just so happens to be where the I/O window is placed
> (both on the PCI side and the AXI (i.e. CPU MMIO) side. Whether it's
> that the external MMIO view of the RC's I/O window is explicitly
> duplicated in its PCI memory space as some side-effect of the PCI/AXI
> bridge, or that the thing just doesn't actually respect the access type
> on the PCI side I don't know, but that's how it is (and I spent this
> morning recreating it to make sure I wasn't mistaken).
What you see is that on your platform the io-ports are accessed by an
mmio-window. On x86 you have dedicated instructions to access io-ports.
And the io-port ranges are what is what the io-resources describe. These
resources do no tell you where the mmio-region for that devices io-ports
are.
Joerg
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[RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Eric Auger <eric.auger@redhat.com> - 2016-11-04 12:30 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Robin Murphy <robin.murphy@arm.com> - 2016-11-04 15:20 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-10 16:50 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Auger Eric <eric.auger@redhat.com> - 2016-11-10 17:00 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-10 17:20 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Auger Eric <eric.auger@redhat.com> - 2016-11-10 19:10 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-11 12:50 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Auger Eric <eric.auger@redhat.com> - 2016-11-11 16:50 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-11 17:30 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Auger Eric <eric.auger@redhat.com> - 2016-11-11 17:50 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-14 16:40 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Auger Eric <eric.auger@redhat.com> - 2016-11-14 17:10 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-14 17:30 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Auger Eric <eric.auger@redhat.com> - 2016-11-14 18:00 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Robin Murphy <robin.murphy@arm.com> - 2016-11-10 17:10 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-10 17:20 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Robin Murphy <robin.murphy@arm.com> - 2016-11-11 15:40 +0100
Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Joerg Roedel <joro@8bytes.org> - 2016-11-11 16:10 +0100
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