On 13 November 2017 at 13:00, Auger Eric <eric.au...@redhat.com> wrote: > On 09/10/2017 19:47, Peter Maydell wrote: >> More generally, why is sysbus-fdt involved in this at all? >> I expected that instantiating and wiring up the SMMU would >> be the job of hw/arm/virt.c, like any other device we >> might have on the board. > I wished to have the same type of option as for x86 where > "-device intel-iommu" is passed to the QEMU command line. smmuv3 device > being a SysBusDevice, a natural framework to handle its node creation > function is sysbus-fdt. Having a -device approach is practical to pass > other options to the device (this was typically the case for the > "caching-mode" option). On Intel there are caching-mode, passthrough > (pt) options.
Not being able to conveniently wire up a sysbus device on the command line or pass it options are general problems. I don't think the SMMU is a special case that should work around these general issues by being created in a different way to everything else. If the "hard to pass options to the device" problem needs solving (which it does anyway if we want to drop '-net' for configuring embedded ethernet devices) we should solve it, not have some small set of sysbus devices be weirdly magic. thanks -- PMM
