On Mon, Jan 22, 2018 at 05:59:00PM +0000, Peter Maydell wrote: > On 22 January 2018 at 17:52, Alexander Monakov <amona...@ispras.ru> wrote: > > Is it feasible to consume a DTB file in Qemu itself to make the board match > > the > > DeviceTree hardware description? For example on Arm there are quite a few > > .dts > > files in Linux tree for various boards; having a "generic" Arm board in > > Qemu that > > could [to what degree?] emulate any of those sounds attractive in theory. > > This is an idea that people have suggested before, and it's certainly > an attractive theory, but unfortunately it doesn't work. The dtb files > contain enough information about the hardware to allow an OS (and in > particular Linux) to boot, but they don't include enough information > in all cases to allow QEMU to create the hardware in the correct way. > > (There are some specialized situations where you can do it, for > instance if you're an SoC manufacturer and you're creating both > hardware and DTB and QEMU model yourself you can ensure that they're > all consistent and generated from the same original information and > the DTB has all the info QEMU needs in it; but we can't do it upstream > in the general case.) > > Also, the main reason we don't have support for a wider range of Arm > boards is that all the devices are different -- it's no good being > able to read a dtb file that says there is a "mediatek,mt6797-uart" at > a particular address if we don't actually have a model of that UART. > Once you have all the device models, wiring up the SoC and board > level code in QEMU isn't really all that difficult (though we could > probably manage to make it a bit less boiler-platy).
Thanks for explaining. Alexander: Thanks for raising the idea for discussion! If you have anything else, please don't hesitate to post on qemu-devel. Stefan
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