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From: Michael Kelley <mikelley@microsoft.com>
To: Mark Rutland <Mark.Rutland@arm.com>
Cc: "will@kernel.org" <will@kernel.org>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
	"sudeep.holla@arm.com" <sudeep.holla@arm.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"wei.liu@kernel.org" <wei.liu@kernel.org>,
	"ardb@kernel.org" <ardb@kernel.org>,
	"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
	KY Srinivasan <kys@microsoft.com>
Subject: RE: [PATCH v10 2/7] arm64: hyperv: Add Hyper-V hypercall and register access utilities
Date: Fri, 14 May 2021 15:14:41 +0000	[thread overview]
Message-ID: <MWHPR21MB1593A7625285A3E3F376B352D7509@MWHPR21MB1593.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20210514125243.GC30645@C02TD0UTHF1T.local>

From: Mark Rutland <mark.rutland@arm.com> Sent: Friday, May 14, 2021 5:53 AM
> 
> On Wed, May 12, 2021 at 10:37:42AM -0700, Michael Kelley wrote:
> > hyperv-tlfs.h defines Hyper-V interfaces from the Hyper-V Top Level
> > Functional Spec (TLFS), and #includes the architecture-independent
> > part of hyperv-tlfs.h in include/asm-generic.  The published TLFS
> > is distinctly oriented to x86/x64, so the ARM64-specific
> > hyperv-tlfs.h includes information for ARM64 that is not yet formally
> > published. The TLFS is available here:
> >
> >   docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs
> >
> > mshyperv.h defines Linux-specific structures and routines for
> > interacting with Hyper-V on ARM64, and #includes the architecture-
> > independent part of mshyperv.h in include/asm-generic.
> >
> > Use these definitions to provide utility functions to make
> > Hyper-V hypercalls and to get and set Hyper-V provided
> > registers associated with a virtual processor.
> >
> > Signed-off-by: Michael Kelley <mikelley@microsoft.com>
> > Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> > ---
> >  MAINTAINERS                          |   3 +
> >  arch/arm64/Kbuild                    |   1 +
> >  arch/arm64/hyperv/Makefile           |   2 +
> >  arch/arm64/hyperv/hv_core.c          | 130 +++++++++++++++++++++++++++++++++++
> >  arch/arm64/include/asm/hyperv-tlfs.h |  69 +++++++++++++++++++
> >  arch/arm64/include/asm/mshyperv.h    |  54 +++++++++++++++
> >  6 files changed, 259 insertions(+)
> >  create mode 100644 arch/arm64/hyperv/Makefile
> >  create mode 100644 arch/arm64/hyperv/hv_core.c
> >  create mode 100644 arch/arm64/include/asm/hyperv-tlfs.h
> >  create mode 100644 arch/arm64/include/asm/mshyperv.h
> 
> > +/*
> > + * hv_do_hypercall- Invoke the specified hypercall
> > + */
> > +u64 hv_do_hypercall(u64 control, void *input, void *output)
> > +{
> > +	struct arm_smccc_res	res;
> > +	u64			input_address;
> > +	u64			output_address;
> > +
> > +	input_address = input ? virt_to_phys(input) : 0;
> > +	output_address = output ? virt_to_phys(output) : 0;
> 
> I may have asked this before, but are `input` and `output` always linear
> map pointers, or can they ever be vmalloc pointers?
> 
> Otherwise, this looks fine to me.
> 

The caller must ensure that hypercall arguments are aligned to
4 Kbytes, and no larger than 4 Kbytes, since that's the page size
used by Hyper-V regardless of the guest page size.  A per-CPU
4 Kbyte memory area (hyperv_pcpu_input_arg) meeting these
requirements is pre-allocated that callers can use for this purpose.
On the x86 side there's also a similar hyperv_pcpu_output_arg,
but there are no use cases for it on ARM64.

Michael

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  reply	other threads:[~2021-05-14 15:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-12 17:37 [PATCH v10 0/7] Enable Linux guests on Hyper-V on ARM64 Michael Kelley
2021-05-12 17:37 ` [PATCH v10 1/7] asm-generic: hyperv: Fix incorrect architecture dependencies Michael Kelley
2021-05-12 17:37 ` [PATCH v10 2/7] arm64: hyperv: Add Hyper-V hypercall and register access utilities Michael Kelley
2021-05-14 12:52   ` Mark Rutland
2021-05-14 15:14     ` Michael Kelley [this message]
2021-05-17 11:44       ` Mark Rutland
2021-05-17 16:41         ` Michael Kelley
2021-05-12 17:37 ` [PATCH v10 3/7] arm64: hyperv: Add Hyper-V clocksource/clockevent support Michael Kelley
2021-05-14 12:37   ` Mark Rutland
2021-05-14 15:35     ` Michael Kelley
2021-05-17 13:08       ` Mark Rutland
2021-05-17 17:27         ` Michael Kelley
2021-05-18 17:00           ` Mark Rutland
2021-06-08 15:36             ` Michael Kelley
2021-06-10 16:45               ` Mark Rutland
2021-06-14  2:42                 ` Michael Kelley
2021-06-16 20:17                   ` Michael Kelley
2021-06-22  9:54                   ` Mark Rutland
2021-06-23  8:56                     ` Marc Zyngier
2021-06-28  2:21                       ` Michael Kelley
2021-05-12 17:37 ` [PATCH v10 4/7] arm64: hyperv: Add kexec and panic handlers Michael Kelley
2021-05-12 17:37 ` [PATCH v10 5/7] arm64: hyperv: Initialize hypervisor on boot Michael Kelley
2021-05-13 15:16   ` Wei Liu
2021-05-12 17:37 ` [PATCH v10 6/7] arm64: efi: Export screen_info Michael Kelley
2021-05-12 17:37 ` [PATCH v10 7/7] Drivers: hv: Enable Hyper-V code to be built on ARM64 Michael Kelley
2021-05-13 13:17 ` [PATCH v10 0/7] Enable Linux guests on Hyper-V " Sudeep Holla

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