On Fri, 2012-09-28 at 11:43 +0200, Joerg Roedel wrote: > On Thu, Sep 27, 2012 at 03:34:07PM -0600, Alex Williamson wrote: > > > It really seems like RMRRs are incompatible with IOMMU API use > > though. > > I don't think so. The concept of RMRR is just not defined well enough > (like the concept of unity mappings on the AMD side which is similar to > RMRR). The definition says, that any memory region must be mapped at > any time for the device. But that is not true (at least I have no > counter-example yet). The right definition would be, that the RMRR > regions are only necessary as long as the operating system does not > control the particular device. And assigning a device to a guest also > counts a 'taking control over the device'.
I think HP folks would be very unhappy with that definition. As David indicates, that's how things like USB use RMRR, but the actual definition in the spec leaves much more room for abuse. Thanks, Alex _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
