Hi, I am wondering how arm xen process the harddisk requests from DomU, is there a daemon in dom0 to do this work? Thanks, Josh _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
As the dom0 can use map_devices_from_device_tree() to map all devices into dom0 memory space , why we need to use the sysmmu ? 2013/8/12 Josh Zhao <joshsystem@gmail.com>> Hi, > I am wondering how arm xen process the harddisk requests from DomU, is > there a daemon in dom0 to do this work? > > Thanks, > > Josh >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Ian Campbell
2013-Aug-13 20:39 UTC
Re: How ARM Xen process the harddisk requests from DomU
On Mon, 2013-08-12 at 12:06 +0800, Josh Zhao wrote:> I am wondering how arm xen process the harddisk requests from DomU, is > there a daemon in dom0 to do this work?Xen on ARM supports only PV devices, so the PV disk backend will deal with it. I''m not sure anyone has tried qdisk on ARM, although it should work fine, but I expect most people are currently using the in-kernel blkback driver in their driver domain. Ian.
Ian Campbell
2013-Aug-13 20:40 UTC
Re: How ARM Xen process the harddisk requests from DomU
On Mon, 2013-08-12 at 14:23 +0800, Josh Zhao wrote:> As the dom0 can use map_devices_from_device_tree() to map all devices > into dom0 memory space , why we need to use the sysmmu ?All ARM domains run with hardware nested page tables ("second stage paging" in ARM speak, equivalent to HAP for x86 HVM guests). So an IOMMU is needed to translate guest physical addresses into host physical addresses for the device e.g. for doing DMA. Ian.