Messages in this thread | | | Subject | RE: [PATCH v5 2/8] arm64: hyperv: Add hypercall and register access functions | Date | Thu, 07 Nov 2019 10:19:56 +0109 | From | Marc Zyngier <> |
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On 2019-11-06 19:08, Michael Kelley wrote: > From: Marc Zyngier <maz@kernel.org> Sent: Wednesday, November 6, > 2019 2:20 AM >> >> 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. >> > > I'll go another round internally with the Hyper-V people on this > topic and impress upon them the desire of the Linux community to > have Hyper-V adopt the true spirit of the spec. But I know they are > fairly set in their approach at this point, regardless of the > technical > merits or lack thereof. Hyper-V is shipping and in use as a > commercial > product on ARM64 hardware, which makes it harder to change. I > hope we can find a way to avoid a complete impasse ....
Hyper-V shipping with their own calling convention is fine by me. Linux having to implement multiple calling conventions because the Hyper-V folks refuse (for undisclosed reason) to adopt the standard isn't fine at all.
HV can perfectly retain its interface for Windows or other things, but please *at least* implement the standard interface on which all existing operating systems rely.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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