From: Marc Zyngier <maz@kernel.org>
To: Michael Kelley <mikelley@microsoft.com>
Cc: mark.rutland@arm.com, linux-hyperv@vger.kernel.org,
"boqun.feng" <boqun.feng@gmail.com>,
catalin.marinas@arm.com, jasowang@redhat.com,
linux-kernel@vger.kernel.org, marcelo.cerri@canonical.com,
olaf@aepfle.de, gregkh@linuxfoundation.org, apw@canonical.com,
devel@linuxdriverproject.org, vkuznets <vkuznets@redhat.com>,
KY Srinivasan <kys@microsoft.com>,
will@kernel.org, Sunil Muthuswamy <sunilmut@microsoft.com>,
linux-arm-kernel@lists.infradead.org
Subject: RE: [PATCH v5 2/8] arm64: hyperv: Add hypercall and register access functions
Date: Thu, 07 Nov 2019 10:19:56 +0109 [thread overview]
Message-ID: <c8403255bf874856c10f07189e27080a@www.loen.fr> (raw)
In-Reply-To: <DM5PR21MB013730D09CB8BA7658DE57F7D7790@DM5PR21MB0137.namprd21.prod.outlook.com>
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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next prev parent reply other threads:[~2019-11-07 9:10 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-03 19:03 [PATCH v5 0/8] Enable Linux guests on Hyper-V on ARM64 Michael Kelley
2019-10-03 19:03 ` [PATCH v5 1/8] arm64: hyperv: Add core Hyper-V include files Michael Kelley
2019-10-03 19:03 ` [PATCH v5 2/8] arm64: hyperv: Add hypercall and register access functions Michael Kelley
2019-11-04 4:36 ` Boqun Feng
2019-11-06 0:40 ` Michael Kelley
2019-11-06 10:19 ` Marc Zyngier
2019-11-06 17:59 ` Michael Kelley
2019-11-07 9:10 ` Marc Zyngier [this message]
2019-11-11 17:16 ` Michael Kelley
2019-10-03 19:03 ` [PATCH v5 3/8] arm64: hyperv: Add memory alloc/free functions for Hyper-V size pages Michael Kelley
2019-11-07 14:19 ` Marc Zyngier
2019-11-08 19:00 ` Michael Kelley
2019-10-03 19:03 ` [PATCH v5 4/8] arm64: hyperv: Add interrupt handlers for VMbus and stimer Michael Kelley
2019-10-03 19:03 ` [PATCH v5 5/8] arm64: hyperv: Add kexec and panic handlers Michael Kelley
2019-10-03 19:03 ` [PATCH v5 6/8] arm64: hyperv: Initialize hypervisor on boot Michael Kelley
2019-10-03 19:03 ` [PATCH v5 7/8] Drivers: hv: vmbus: Add hooks for per-CPU IRQ Michael Kelley
2019-10-03 19:03 ` [PATCH v5 8/8] Drivers: hv: Enable Hyper-V code to be built on ARM64 Michael Kelley
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