lkml.org 
[lkml]   [2011]   [Nov]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] iommu: Include MSI susceptibility to DMA in creating iommu groups
* Joerg Roedel (joro@8bytes.org) wrote:
> >From device standpoint a MSI transaction is always a DMA memory write
> to a given address range. The IOMMU-API should export a feature flag
> whether it supports filtering on those transaction or not. We have that
> today with the IOMMU_CAP_INTR_REMAP. I agree that the interface to get
> this information is ugly because a domain is needed. But the interface
> can be fixed. While doing this I suggest to rename that feature
> IOMMU_CAP_INTR_ISOLATION or something like that.
> VFIO can then check for this flag on module-load and refuse to load if
> it is not available.

I can see that the native grouping (the typical pci bridge type) is
really more a property of the topology.

The isolation properties of a group (arguably the whole point of the
group) is subtly different.

Leaves the questions:

What is the value of a group w/out complete isolation?
Is there a practical problem w/ conflating the subtleties above?

thanks,
-chris


\
 
 \ /
  Last update: 2011-11-22 00:37    [W:0.062 / U:0.956 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site