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>

1 files changed, 54 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
new file mode 100644
index 000000000000..20070a847304
--- /dev/null
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -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