A patch making it to a TIP Git branch this week adds Linux kernel support for detecting the FreeBSD Bhyve hypervisor, which will become important with today’s growing server CPU counts.
As covered originally a few days ago, the Linux kernel has been working on Bhyve hypervisor detection for being able to support more than 255 vCPUs. The FreeBSD 15.0 release coming out in December has 15-bit MSI enlightenment support for being able to handle more than 255 vCPUs. Thus for Linux VM usage with Bhyve there’s now a need for this hypervisor detection.
This patch made it into tip/tip.git’s “x86/cpu” Git branch this week. With that milestone now achieved, the support should be merged in the coming weeks with the Linux 6.18 merge window.
“x86/cpu: Detect FreeBSD Bhyve hypervisor
Detect the Bhyve hypervisor and enable 15-bit MSI support if available.
Detecting Bhyve used to be a purely cosmetic issue of the kernel printing ‘Hypervisor detected: Bhyve’ at boot time.
But FreeBSD 15.0 will support¹ the 15-bit MSI enlightenment to support more than 255 vCPUs which means there’s now actually some functional reason to do so.”
Both FreeBSD 15.0 and Linux 6.18 should coincidentally see their stable releases in December.
