For months Broadcom has been working on the VMware Hypercall API for the Linux kernel. This "vmware_hyperscall" is a new family of functions for use by the VMware guest code and virtual device drivers in an architecture-independent manner.

The VMware Hypercall API aims to improve upon existing VMware guest / virtual device support in a more CPU architecture independent manner. It is said that this new VMware Hypercall API will also improve the enablement of other new features in the VMware virtualization space such as for Intel TDX and AMD SEV-ES.

The latest [1]patch series this week sums up the VMware Hypercall API effort for the Linux kernel as:

"VMware hypercalls invocations were all spread out across the kernel implementing same ABI as in-place asm-inline. With encrypted memory and confidential computing it became harder to maintain every changes in these hypercall implementations.

Intention of this patchset is to introduce arch independent VMware hypercall API layer other subsystems such as device drivers can call to, while hiding architecture specific implementation behind.

First patch introduces the vmware_hypercall low and high bandwidth families of functions, with little enhancements there. And the last patch adds tdx hypercall support."

These patches were briefly [2]queued into tip/tip.git's "x86/vmware" branch. But besides the time of seeing this activity on Saturday and writing the article today, the x86/vmware branch appears to have been reset. But in any event it looks like this VMware Hypercall API support is about ready for mainlining and so hopefully these patches will reappear within TIP's x86/vmware branch ahead of the Linux 6.11 merge window opening up in mid-July.



[1] https://lore.kernel.org/all/20240613191650.9913-1-alexey.makhalov@broadcom.com/

[2] https://lore.kernel.org/lkml/171843970672.10875.12481364592821283411.tip-bot2@tip-bot2/