Commit 57d276bb authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

arm64: hyperv: Add Hyper-V hypercall and register access utilities 



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: default avatarMichael Kelley <mikelley@microsoft.com>
Reviewed-by: default avatarSunil Muthuswamy <sunilmut@microsoft.com>
Acked-by: default avatarMarc Zyngier <maz@kernel.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1628092359-61351-2-git-send-email-mikelley@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent e5d9b714

MAINTAINERS

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@@ -8594,6 +8594,9 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git 
F:	Documentation/ABI/stable/sysfs-bus-vmbus

F:	Documentation/ABI/testing/debugfs-hyperv

F:	Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst

F:	arch/arm64/hyperv

F:	arch/arm64/include/asm/hyperv-tlfs.h

F:	arch/arm64/include/asm/mshyperv.h

F:	arch/x86/hyperv

F:	arch/x86/include/asm/hyperv-tlfs.h

F:	arch/x86/include/asm/mshyperv.h

arch/arm64/Kbuild

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@@ -2,4 +2,5 @@ 
obj-y			+= kernel/ mm/ net/

obj-$(CONFIG_KVM)	+= kvm/

obj-$(CONFIG_XEN)	+= xen/

obj-$(subst m,y,$(CONFIG_HYPERV))	+= hyperv/

obj-$(CONFIG_CRYPTO)	+= crypto/

arch/arm64/hyperv/Makefile

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# SPDX-License-Identifier: GPL-2.0

obj-y		:= hv_core.o

arch/arm64/hyperv/hv_core.c

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// SPDX-License-Identifier: GPL-2.0



/*

 * Low level utility routines for interacting with Hyper-V.

 *

 * Copyright (C) 2021, Microsoft, Inc.

 *

 * Author : Michael Kelley <mikelley@microsoft.com>

 */



#include <linux/types.h>

#include <linux/export.h>

#include <linux/mm.h>

#include <linux/hyperv.h>

#include <linux/arm-smccc.h>

#include <linux/module.h>

#include <asm-generic/bug.h>

#include <asm/hyperv-tlfs.h>

#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;



	arm_smccc_1_1_hvc(HV_FUNC_ID, control,

			  input_address, output_address, &res);

	return res.a0;

}

EXPORT_SYMBOL_GPL(hv_do_hypercall);



/*

 * hv_do_fast_hypercall8 -- Invoke the specified hypercall

 * with arguments in registers instead of physical memory.

 * Avoids the overhead of virt_to_phys for simple hypercalls.

 */



u64 hv_do_fast_hypercall8(u16 code, u64 input)

{

	struct arm_smccc_res	res;

	u64			control;



	control = (u64)code | HV_HYPERCALL_FAST_BIT;



	arm_smccc_1_1_hvc(HV_FUNC_ID, control, input, &res);

	return res.a0;

}

EXPORT_SYMBOL_GPL(hv_do_fast_hypercall8);



/*

 * Set a single VP register to a 64-bit value.

 */

void hv_set_vpreg(u32 msr, u64 value)

{

	struct arm_smccc_res res;



	arm_smccc_1_1_hvc(HV_FUNC_ID,

		HVCALL_SET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |

			HV_HYPERCALL_REP_COMP_1,

		HV_PARTITION_ID_SELF,

		HV_VP_INDEX_SELF,

		msr,

		0,

		value,

		0,

		&res);



	/*

	 * Something is fundamentally broken in the hypervisor if

	 * setting a VP register fails. There's really no way to

	 * continue as a guest VM, so panic.

	 */

	BUG_ON(!hv_result_success(res.a0));

}

EXPORT_SYMBOL_GPL(hv_set_vpreg);



/*

 * Get the value of a single VP register.  One version

 * returns just 64 bits and another returns the full 128 bits.

 * The two versions are separate to avoid complicating the

 * calling sequence for the more frequently used 64 bit version.

 */



void hv_get_vpreg_128(u32 msr, struct hv_get_vp_registers_output *result)

{

	struct arm_smccc_1_2_regs args;

	struct arm_smccc_1_2_regs res;



	args.a0 = HV_FUNC_ID;

	args.a1 = HVCALL_GET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |

			HV_HYPERCALL_REP_COMP_1;

	args.a2 = HV_PARTITION_ID_SELF;

	args.a3 = HV_VP_INDEX_SELF;

	args.a4 = msr;



	/*

	 * Use the SMCCC 1.2 interface because the results are in registers

	 * beyond X0-X3.

	 */

	arm_smccc_1_2_hvc(&args, &res);



	/*

	 * Something is fundamentally broken in the hypervisor if

	 * getting a VP register fails. There's really no way to

	 * continue as a guest VM, so panic.

	 */

	BUG_ON(!hv_result_success(res.a0));



	result->as64.low = res.a6;

	result->as64.high = res.a7;

}

EXPORT_SYMBOL_GPL(hv_get_vpreg_128);



u64 hv_get_vpreg(u32 msr)

{

	struct hv_get_vp_registers_output output;



	hv_get_vpreg_128(msr, &output);



	return output.as64.low;

}

EXPORT_SYMBOL_GPL(hv_get_vpreg);

arch/arm64/include/asm/hyperv-tlfs.h

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/* SPDX-License-Identifier: GPL-2.0 */



/*

 * This file contains definitions from the Hyper-V Hypervisor Top-Level

 * Functional Specification (TLFS):

 * https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs

 *

 * Copyright (C) 2021, Microsoft, Inc.

 *

 * Author : Michael Kelley <mikelley@microsoft.com>

 */



#ifndef _ASM_HYPERV_TLFS_H

#define _ASM_HYPERV_TLFS_H



#include <linux/types.h>



/*

 * All data structures defined in the TLFS that are shared between Hyper-V

 * and a guest VM use Little Endian byte ordering.  This matches the default

 * byte ordering of Linux running on ARM64, so no special handling is required.

 */



/*

 * These Hyper-V registers provide information equivalent to the CPUID

 * instruction on x86/x64.

 */

#define HV_REGISTER_HYPERVISOR_VERSION		0x00000100 /*CPUID 0x40000002 */

#define HV_REGISTER_FEATURES			0x00000200 /*CPUID 0x40000003 */

#define HV_REGISTER_ENLIGHTENMENTS		0x00000201 /*CPUID 0x40000004 */



/*

 * Group C Features. See the asm-generic version of hyperv-tlfs.h

 * for a description of Feature Groups.

 */



/* Crash MSRs available */

#define HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE	BIT(8)



/* STIMER direct mode is available */

#define HV_STIMER_DIRECT_MODE_AVAILABLE		BIT(13)



/*

 * Synthetic register definitions equivalent to MSRs on x86/x64

 */

#define HV_REGISTER_CRASH_P0		0x00000210

#define HV_REGISTER_CRASH_P1		0x00000211

#define HV_REGISTER_CRASH_P2		0x00000212

#define HV_REGISTER_CRASH_P3		0x00000213

#define HV_REGISTER_CRASH_P4		0x00000214

#define HV_REGISTER_CRASH_CTL		0x00000215



#define HV_REGISTER_GUEST_OSID		0x00090002

#define HV_REGISTER_VP_INDEX		0x00090003

#define HV_REGISTER_TIME_REF_COUNT	0x00090004

#define HV_REGISTER_REFERENCE_TSC	0x00090017



#define HV_REGISTER_SINT0		0x000A0000

#define HV_REGISTER_SCONTROL		0x000A0010

#define HV_REGISTER_SIEFP		0x000A0012

#define HV_REGISTER_SIMP		0x000A0013

#define HV_REGISTER_EOM			0x000A0014



#define HV_REGISTER_STIMER0_CONFIG	0x000B0000

#define HV_REGISTER_STIMER0_COUNT	0x000B0001



#include <asm-generic/hyperv-tlfs.h>



#endif