[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] Questioning the Xen Design of the VMM
On Thu, 2006-08-10 at 18:34 +0200, Petersson, Mats wrote: > Context-switching is only part of the problem, as Daniel says. > IOMMU is a technology that is coming in future products from AMD > (and I'm sure Intel are working on such products as well. > IBM already have a chipset in production for some of the PowerPC > and x86-based servers). i didn't have a look yet at the papers from amd, but it may be of interest that the PCI interfaces (1998, maybe even earlier) built by sun for their ultrasparc processors already implemented such a beast. al, docs on the bridge should be available from sun online, if you're interested in such things. the basic idea being virtualization of the I/O address space, this feature is quite cool even if you don't give a single thought about system virtualization (sun probably didn't at that point). getting your hands on contiguous, dma-able memory areas can be a permanent headache in os and device driver design if you peripheral bus seeks physical memory untranslated. put a translation table in between and upstream transactions become a non-issue, without offloading any additional logic into the peripheral bus interface. mats, i suppose amd's iommu solves this as well? regards, daniel -- Daniel Stodden LRR - Lehrstuhl fÃr Rechnertechnik und Rechnerorganisation Institut fÃr Informatik der TU MÃnchen D-85748 Garching http://www.lrr.in.tum.de/~stodden mailto:stodden@xxxxxxxxxx PGP Fingerprint: F5A4 1575 4C56 E26A 0B33 3D80 457E 82AE B0D8 735B Attachment:
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