[PATCH v5 03/10] arm64/hyperv: Add some missing functions to arm64

Nuno Das Neves
2025-02-26T23:08:59Z

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

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
---
arch/arm64/hyperv/hv_core.c | 17 +++++++++++++++++
arch/arm64/include/asm/mshyperv.h | 12 ++++++++++++
include/asm-generic/mshyperv.h | 2 ++
3 files changed, 31 insertions(+)

diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
index 69004f619c57..e33a9e3c366a 100644
--- a/arch/arm64/hyperv/hv_core.c
+++ b/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.
*/
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index 2e2f83bafcfb..2a900ba00622 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -40,6 +40,18 @@ 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( \
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index c020d5d0ec2a..258034dfd829 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -72,6 +72,8 @@ 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);
+extern u64 hv_do_fast_hypercall16(u16 control, u64 input1, u64 input2);
+
bool hv_isolation_type_snp(void);
bool hv_isolation_type_tdx(void);

--
2.34.1