arm64/hyperv: Add some missing functions to arm64

These non-nested msr and fast hypercall functions are present in x86,
but they must be available in both architectures for the root partition
driver code.

While at it, remove the redundant 'extern' keywords from the
hv_do_hypercall() variants in asm-generic/mshyperv.h.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
Link: https://lore.kernel.org/r/1741980536-3865-4-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1741980536-3865-4-git-send-email-nunodasneves@linux.microsoft.com>

Author: NunoDasNeves

arch/arm64/hyperv/hv_core.c

@@ -53,6 +53,23 @@ u64 hv_do_fast_hypercall8(u16 code, u64 input)
 }
 EXPORT_SYMBOL_GPL(hv_do_fast_hypercall8);
 
+/*
+ * hv_do_fast_hypercall16 -- 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_hypercall16(u16 code, u64 input1, u64 input2)
+{
+	struct arm_smccc_res	res;
+	u64			control;
+
+	control = (u64)code | HV_HYPERCALL_FAST_BIT;
+
+	arm_smccc_1_1_hvc(HV_FUNC_ID, control, input1, input2, &res);
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(hv_do_fast_hypercall16);
+
 /*
  * Set a single VP register to a 64-bit value.
  */

arch/arm64/include/asm/mshyperv.h

@@ -40,6 +40,19 @@ static inline u64 hv_get_msr(unsigned int reg)
 	return hv_get_vpreg(reg);
 }
 
+/*
+ * Nested is not supported on arm64
+ */
+static inline void hv_set_non_nested_msr(unsigned int reg, u64 value)
+{
+	hv_set_msr(reg, value);
+}
+
+static inline u64 hv_get_non_nested_msr(unsigned int reg)
+{
+	return hv_get_msr(reg);
+}
+
 /* SMCCC hypercall parameters */
 #define HV_SMCCC_FUNC_NUMBER	1
 #define HV_FUNC_ID	ARM_SMCCC_CALL_VAL(			\

include/asm-generic/mshyperv.h

@@ -70,8 +70,10 @@ extern enum hv_partition_type hv_curr_partition_type;
 extern void * __percpu *hyperv_pcpu_input_arg;
 extern void * __percpu *hyperv_pcpu_output_arg;
 
-extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
-extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
+u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
+u64 hv_do_fast_hypercall8(u16 control, u64 input8);
+u64 hv_do_fast_hypercall16(u16 control, u64 input1, u64 input2);
+
 bool hv_isolation_type_snp(void);
 bool hv_isolation_type_tdx(void);