On 11/22/22 17:56, Dexuan Cui wrote:

quoted

From: Dexuan Cui
[...]
The existing asm code for __tdx_hypercall() passes through R10~R15
(see TDVMCALL_EXPOSE_REGS_MASK) to the (KVM) hypervisor.

Unluckily, for Hyper-V, we need to pass through RDX, R8, R10 and R11
to Hyper-V, so I don't think I can use the existing __tdx_hypercall() ?

I'm checking with the Hyper-V team to see if it's possible for them
to not use RDX and R8, and use R12 and R13 instead. Will keep the
thread updated.

That would be nice.  But, to be honest, I don't expect them to change
the ABI for one OS.  It's not a big deal to just make the function a bit
more flexible.