Re: [PATCH v5 2/8] arm64: hyperv: Add hypercall and register access functions

From: Marc Zyngier
Date: Wed Nov 06 2019 - 05:19:18 EST


On 2019-10-03 20:12, Michael Kelley wrote:
Add ARM64-specific code to make Hyper-V hypercalls and to
access virtual processor synthetic registers via hypercalls.
Hypercalls use a Hyper-V specific calling sequence with a non-zero
immediate value per Section 2.9 of the SMC Calling Convention
spec.

I find this "following the spec by actively sidestepping it" counter
productive. You (or rather the Hyper-V people) are reinventing the
wheel (of the slightly square variety) instead of using the standard
that the whole of the ARM ecosystem seems happy to take advantage
of.

I wonder what is the rational for this. If something doesn't quite
work for Hyper-V, I think we'd all like to know.

Thanks,

M.
--
Jazz is not dead. It just smells funny...