1 files changed, 129 insertions, 0 deletions
diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
new file mode 100644
index 000000000000..4c5dc0f51b12
--- /dev/null
+++ b/arch/arm64/hyperv/hv_core.c
@@ -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);