[PATCH 0/4] Add support for updated vmware hypercall instruction

From: Thomas HellstrÃm (VMware)
Date: Sun Aug 18 2019 - 10:40:39 EST


Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: <x86@xxxxxxxxxx>
Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Cc: <linux-input@xxxxxxxxxxxxxxx>

VMware has started using "vmcall" / "vmmcall" instead of an inl instruction
for the "backdoor" interface. This series detects support for those
instructions.
Outside of the platform code we use the "ALTERNATIVES" self-patching
mechanism similarly to how this is done with KVM.
Unfortunately we need two x86 cpu feature flags for this, since we need
the default instruction to be "inl". IIRC the vmmouse driver is used by
other virtualization solutions than VMware, and those might break if
they encounter any of the other instructions.