NetBSD microvm, Git, and PV Clock
Tom and I had a call today discussing commit history pertaining to the NetBSD microvm implementation, viewing Git logs locally, and next steps regarding the PV clock driver.
NetBSD microvm Commits
Tom knew that the user iMil is the primary contributor for the NetBSD microvm implementation. On Github, his commits to the NetBSD source are found at https://github.com/NetBSD/src/commits?author=iMilnb. They’re easy to parse since, as of today, he has done a relatively small number of commits to the project, and all of them but one from 2009 pertain to the microvm port.
Git Logs
To more effectively view Git logs locally, Tom provided the following list of Git commands:
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git log # show everything that has happened in the source tree chronologically
git log . # show log for this directory
git log --author="Tom Jones" # show Tom Jones' commits
git log --stat # show the files changed and their churn for commit log
git log -p # show a patch along with commit
git show <commit> # show log and changes for a commit
git log <file> # show all changes for a file
PV Clock
It may be worth looking into using PV clock in the microvm build instead of TSC. We previously disabled it entirely to bypass a TSC KASSERT, but my assumption is that we shouldn’t be getting to the check in the first place if things are properly configured. The PV clock driver implementation in FreeBSD is located at sys/x86/x86/pvclock.c.
If it’s at all helpful, we also noted that OpenBSD has a PV clock driver implementation. A minimal manpage for the driver is located at https://man.openbsd.org/pvclock.4. This may or may not be helpful in figuring out what PV clock is, as I currently don’t know too much about it. Either way, if changing the configuration doesn’t work right away, which it probably won’t, I’ll want to look more into what the PV clock actually is.