If you have MACHINE set to qemuarm and then run devtool modify virtual/kernel you get the following error: ----------- snip ----------- INFO: Copying kernel config to workspace Traceback (most recent call last): File "/data/poky/scripts/devtool", line 334, in <module> ret = main() File "/data/poky/scripts/devtool", line 321, in main ret = args.func(args, config, basepath, workspace) File "/data/poky/scripts/lib/devtool/standard.py", line 844, in modify shutil.copy2(os.path.join(kconfpath, '.config'),srctree) File "/usr/lib/python3.6/shutil.py", line 257, in copy2 copyfile(src, dst, follow_symlinks=follow_symlinks) File "/usr/lib/python3.6/shutil.py", line 120, in copyfile with open(src, 'rb') as fsrc: FileNotFoundError: [Errno 2] No such file or directory: '/data/poky/build/tmp/work/qemuarm-poky-linux-gnueabi/linux-yocto/5.2.17+gitAUTOINC+b867b78b50_255a750d28-r0/linux-qemuarm-standard-build/.config' ----------- snip ----------- The actual workdir is at /data/poky/build/tmp/work/qemuarm-poky-linux-gnueabi/linux-yocto/5.2.17+gitAUTOINC+b867b78b50_47b80ef7bd-r0/ so it's using the wrong SRCREV. The same thing works fine with MACHINE = "qemux86", so I suspect that it's using the generic SRCREV rather than the one for the machine, given that qemuarm has its own custom value (see meta/recipes-kernel/linux/linux-yocto_5.2.bb) whereas qemux86 uses the same hash as the generic SRCREV.
http://git.yoctoproject.org/cgit.cgi/poky/commit/?id=d427f58977a46f2bda4b7f30cf83793373e401d3