Re: Initialize data memory in user space emulation

["Libo Zhou" <zhlb29@foxmail.com>]

I actually thought about hacking it to mmap from file into guest memory before running ELF. In include/exec/memory.h, the function memory_region_init_ram_from_file sounds like what I need. But the entire memory.h source file is wrapped by #ifndef CONFIG_USER_ONLY, I cannot use that API in user space emulation, right?

------------------ Original ------------------
From:  "Peter Maydell";<peter.maydell@linaro.org>;
Send time: Friday, Sep 20, 2019 10:55 PM
To: "Libo Zhou"<zhlb29@foxmail.com>; 
Cc: "qemu-devel"<qemu-devel@nongnu.org>; 
Subject:  Re: Initialize data memory in user space emulation

On Fri, 20 Sep 2019 at 15:49, Libo Zhou <zhlb29@foxmail.com> wrote:
> I need to emulate a Digital Signal Processor. The DSP essentially has only basic MIPS ISA, and it manipulates the data stored in a "data memory". I can run an ELF with user space emulation, what I need to additionally do is to initialize the "data memory" first, then run an ELF that manipulates the data in the "data memory", and finally see if the resulting data are correct or not.

QEMU doesn't really support doing that kind of thing, because
actual Linux binaries don't execute in an environment like that.
You could probably hack QEMU to mmap a file into the guest's
memory before we start to run the userspace process, but there's
nothing that will do what you want out of the box.

thanks
-- PMM