Maybe I was wrong about it bypassing windows, IDK but it's certainly not all on-top of Windows.
To my knowledge:
- Cygwin is a "translation layer" between Win32 and POSIX user-mode APIs created as a c library and distributed in a Windows style DLL file (for Cygwin compiled windows binaries of for-Linux user-mode software) see http://cygwin.com/faq.html#faq.api.everything & http://superuser.com/a/729393.
- KVM is a Linux device-driver which has to directly communicate with the OS's kernel (last time I used KVM I had to rebuild my Linux kernel from [patched] sources to add KVM support), thus I wouldn't think that Cygwin would support compiling KVM at all.
So what it looks to me like they've done is to develop a driver with similar purpose to Cygwin but for translating Linux kernel functions to Windows kernel APIs, then to put a piece of Cygwin-based user-mode software running under Windows to interface with it. However since Windows' kernel doesn't have equivalents to all
the functions Linux's kernel needs to have for KVM to function they apparently had to directly use portions of Linux's kernel in their driver, this runs on the hardware itself without (much) communication with Windows' own kernel, and since you now basically have (portions of) two kernels running on the same hardware at the same time without really knowing that the other ones there (AFAIK there are no predefined rules for how such interaction would take place) they can (and do) step on each-others toes. Thus all kinds of weird bugs, and since it's not being developed any more none of the bugs are getting fixed.
Note my interpretation could be totally off base, but that's how I (currently) understand it, if someone who really knows
what's going on can explain it, please do.
Darn it looks like we got off topic again.
Now to go WAY back on-topic:
I was going to edit the wiki to show that qemu's USB tablet option works in current builds, but I'm not sure about the ReactOS wiki's hardware support status updating etiquette.
Should I replace the already existing note stating that it "Failed" with r59118, or am I supposed to add another "Works" entry for 0.13.16 & r62690+ with ssam & I in the tester cell and a comment stating that ssam tested under Fedora 20 w/ qemu & qemu-kvm & I tested under Windows 7 Pro x64? (or is there another way that it should be done which I've not thought of?)