Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1521826

Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback

From Joerg Roedel <joro@8bytes.org>
Newsgroups linux.kernel
Subject Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback
Date 2016-11-14 17:30 +0100
Message-ID <sDsiR-Vh-29@gated-at.bofh.it> (permalink)
References (5 earlier) <sCmfv-68Q-1@gated-at.bofh.it> <sCmSd-6F5-1@gated-at.bofh.it> <sCnbz-6LA-1@gated-at.bofh.it> <sDrwu-l5-21@gated-at.bofh.it> <sDrZw-Nx-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Mon, Nov 14, 2016 at 05:08:16PM +0100, Auger Eric wrote:
> There are potentially several MSI doorbell physical pages in the SOC
> that are accessed through the IOMMU (translated). Each of those must
> have a corresponding IOVA and IOVA/PA mapping programmed in the IOMMU.
> Else MSI will fault.
> 
> - step 1 was to define a usable IOVA range for MSI mapping. So now we
> decided the base address and size would be hardcoded for ARM. The
> get_dm_region can be used to retrieve that hardcoded region.
> - Step2 is to allocate IOVAs within that range and map then for each of
> those MSI doorbells. This is done in the MSI controller compose() callback.
> 
> I hope I succeeded in clarifying this time.
> 
> Robin sent today a new version of its cookie think using a dummy
> allocator. I am currently integrating it.

Okay, I understand. A simple bitmap-allocator would probably be
sufficient, and doesn't have the overhead the iova allocator has. About
how many pages are we talking here?


	Joerg

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

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

csiph-web