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: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1628092359-61351-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Michael Kelley 2021-08-04 08:52:35 -07:00 committed by Wei Liu
parent e5d9b714fe
commit 57d276bbbd
6 changed files with 258 additions and 0 deletions

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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

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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/

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@ -0,0 +1,2 @@
# SPDX-License-Identifier: GPL-2.0
obj-y := hv_core.o

129
arch/arm64/hyperv/hv_core.c Normal file
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@ -0,0 +1,129 @@
// 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);

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@ -0,0 +1,69 @@
/* 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

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@ -0,0 +1,54 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Linux-specific definitions for managing interactions with Microsoft's
* Hyper-V hypervisor. The definitions in this file are specific to
* the ARM64 architecture. See include/asm-generic/mshyperv.h for
* definitions are that architecture independent.
*
* Definitions that are specified in the Hyper-V Top Level Functional
* Spec (TLFS) should not go in this file, but should instead go in
* hyperv-tlfs.h.
*
* Copyright (C) 2021, Microsoft, Inc.
*
* Author : Michael Kelley <mikelley@microsoft.com>
*/
#ifndef _ASM_MSHYPERV_H
#define _ASM_MSHYPERV_H
#include <linux/types.h>
#include <linux/arm-smccc.h>
#include <asm/hyperv-tlfs.h>
/*
* Declare calls to get and set Hyper-V VP register values on ARM64, which
* requires a hypercall.
*/
void hv_set_vpreg(u32 reg, u64 value);
u64 hv_get_vpreg(u32 reg);
void hv_get_vpreg_128(u32 reg, struct hv_get_vp_registers_output *result);
static inline void hv_set_register(unsigned int reg, u64 value)
{
hv_set_vpreg(reg, value);
}
static inline u64 hv_get_register(unsigned int reg)
{
return hv_get_vpreg(reg);
}
/* SMCCC hypercall parameters */
#define HV_SMCCC_FUNC_NUMBER 1
#define HV_FUNC_ID ARM_SMCCC_CALL_VAL( \
ARM_SMCCC_STD_CALL, \
ARM_SMCCC_SMC_64, \
ARM_SMCCC_OWNER_VENDOR_HYP, \
HV_SMCCC_FUNC_NUMBER)
#include <asm-generic/mshyperv.h>
#endif