On Mon, May 23, 2016 at 05:01:28PM +0300, Marcel Apfelbaum wrote: > This is a proposal on how to create the iommu with > '-device intel-iommu' instead of '-machine,iommu=on'. > > The device is part of the machine properties because we wanted > to ensure it is created before any other PCI device. > > The alternative is to skip the bus_master_enable_region at > the time the device is created. We can create this region > at machine_done phase. (patch 1) > > Then we can enable sysbus devices for PC machines and make all the > init steps inside the iommu realize function. (patch 2) > > The series is working, but a lot of issues are not resolved: > - minimum testing was done > - the iommu addr should be passed (maybe) in command line rather than > hard-coded > - enabling sysbus devices for PC machines is risky, I am not aware yet > of the side effects of this modification. > - I am not sure moving the bus_master_enable_region to machine_done > is with no undesired effects.
I gave it a shot on the patches and it works nicely (of course no complex configurations, like hot plug). Could you help introduce what will bring us if we use "-device" rather than "-M" options? Benefits I can see is that, we can specify parameters with specific device, rather than messing them up in "machine" options. Do we have any other benefits that I may have missed? Thanks! -- peterx
