Re: [Qemu-devel] Question on pointers in the qemu user space emulation

[Peter Maydell]

On 17 January 2014 06:33, Erik de Castro Lopo <address@hidden> wrote:
> I'm currently working on implementing a missing part of a linux-user
> syscall. This syscall includes a function pointer for a callback.

Which syscall? Callbacks from the kernel are pretty tricky.
Basically you need to register a host function as the callback
with the host kernel, and stash the guest function pointer somewhere
so that when the callback comes in from the host kernel you can
arrange to interrupt the guest and restart it at the desired
location.

Pretty much the only situation we support this for is the special
case of signal handlers. In fact I wasn't even aware there was
any other kind of kernel-to-userspace callback...

thanks
-- PMM