Add Bochs user mode emulator like SDE or QEMU

[stlintel]

For QEMU it is: QEMU User space emulator, mentioned in QEMU docs: https://www.qemu.org/docs/master/user/main.html

I believe code from QEMU could be heavily reused as well

[stlintel]

In ideal world instead of copying console linux binary into Bochs and running I would

bochs [-h] [-d] [-L path] [-s size] [-cpu model] [-g port] [-B offset] program [arguments...]

[Vort]

Bochs is a portable IA-32 (x86) PC emulator

From your link:

In this mode, QEMU can launch processes compiled for one CPU on another CPU.

Launching processes and emulating computers are different things in my opinion.

[stlintel]

Intel SDE is also emulator of CPU as well as QEMU. For Intel SDE it is mainly to emulate future ISA, for QEMU it is to emulate one ISA on another.

But for this feature main advantage is abstraction from disk images and guest operating system. In my CPU validation code I compare Bochs implementation to SDE implementation on automatically generated unit tests, one per instruction. I generate one instruction like VDPBF16PS with millions of random inputs and compare results against same thing running on SDE. Running it locally without uploading to disk image and downloading results would be huge advantage.

How I see it ? Smth similar to Load32OSHack feature we had many years ago and deprecated.

• Set up CPU to pre-defined state matching one running under linux
• load ELF file with binary
• allocate memory for the ELF file in host memory by creating page tables on the fly
• map system calls from ELF to corresponding host handlers or, in future, emulated handlers
• transfer control to the ELF by setting RIP=ELF_START and running cpu_loop()

[Vort]

Running it locally without uploading to disk image and downloading results would be huge advantage.

With SSH access to guest there should not be many problems in automating this task. It looks like it can be done with relatively simple script. Am I missing something?