linux/arch/arm64/hyperv/hv_core.c
Michael Kelley 57d276bbbd 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>
2021-08-04 16:54:36 +00:00

130 lines
3.0 KiB
C

// 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);