On Sunday, 17 July 2016 18:56:25 CEST Peter Maydell wrote: > On 16 July 2016 at 23:38, Federico Vaga <federico.v...@vaga.pv.it> wrote: > > I'm super new to qemu and I would like to understand more about the > > hardware components emulation. I surfed for some hours on the internet > > but I cannot find much help. > > By looking at the source code in the 'hw' directory of the qemu git > > repository I can vaguely guess how it works but I would like to see some > > explainations: a manual. > > Sorry, we don't really have much internals documentation. The > source code is the most accurate reference.
It's a pity :( If we end up to use QEMU maybe I will write a couple of lines :) > Most devices are > fairly straightforward: they implement one (occasionally more) > MemoryRegion, which corresponds to a bank of registers that > will be mapped into the emulated system's address maps. And > they provide also some interrupt (irq) lines and perhaps some > input or output GPIO lines. What device would you suggest to look at? > > Then a question. Are these hardware modules dynamically loadable by qemu > > as > > external modules? I mean, can I compile a hardware component out of the > > qemu tree and load it in the qemu I get from the distro? In other words: > > I would like to have something like Linux kernel modules (.ko) that I > > attach to qemu when I launch it. > > No, we don't have devices as modules. We do have some module > support, but this is intended primarily to allow distributions > to split out parts of QEMU which have dependencies on > external shared libraries, so that users who don't need > (for instance) the glusterfs support can just not install > the optional QEMU modules rather than having to pull in > a lot of dependent packages for a feature they're not using. > Our modules code (deliberately) does not support loading a > module from one compile into a QEMU built with another > compile -- there is no stable API/ABI within QEMU. So > loading a separate module into a distro-supplied QEMU will > not work. I see. Does it make sense to have it at some point in the future? -- Federico Vaga
