selftests: KVM: Create helper for making SMCCC calls

The PSCI and PV stolen time tests both need to make SMCCC calls within
the guest. Create a helper for making SMCCC calls and rework the
existing tests to use the library function.

Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220504032446.4133305-10-oupton@google.com

diff --git a/tools/testing/selftests/kvm/aarch64/psci_test.c b/tools/testing/selftests/kvm/aarch64/psci_test.c
index 4c5f681..8c998f0 100644 (file)
--- a/tools/testing/selftests/kvm/aarch64/psci_test.c
+++ b/tools/testing/selftests/kvm/aarch64/psci_test.c
@@ -26,32 +26,23 @@
 static uint64_t psci_cpu_on(uint64_t target_cpu, uint64_t entry_addr,
                            uint64_t context_id)
 {
-       register uint64_t x0 asm("x0") = PSCI_0_2_FN64_CPU_ON;
-       register uint64_t x1 asm("x1") = target_cpu;
-       register uint64_t x2 asm("x2") = entry_addr;
-       register uint64_t x3 asm("x3") = context_id;
+       struct arm_smccc_res res;
 
-       asm("hvc #0"
-           : "=r"(x0)
-           : "r"(x0), "r"(x1), "r"(x2), "r"(x3)
-           : "memory");
+       smccc_hvc(PSCI_0_2_FN64_CPU_ON, target_cpu, entry_addr, context_id,
+                 0, 0, 0, 0, &res);
 
-       return x0;
+       return res.a0;
 }
 
 static uint64_t psci_affinity_info(uint64_t target_affinity,
                                   uint64_t lowest_affinity_level)
 {
-       register uint64_t x0 asm("x0") = PSCI_0_2_FN64_AFFINITY_INFO;
-       register uint64_t x1 asm("x1") = target_affinity;
-       register uint64_t x2 asm("x2") = lowest_affinity_level;
+       struct arm_smccc_res res;
 
-       asm("hvc #0"
-           : "=r"(x0)
-           : "r"(x0), "r"(x1), "r"(x2)
-           : "memory");
+       smccc_hvc(PSCI_0_2_FN64_AFFINITY_INFO, target_affinity, lowest_affinity_level,
+                 0, 0, 0, 0, 0, &res);
 
-       return x0;
+       return res.a0;
 }
 
 static void guest_main(uint64_t target_cpu)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 8f9f469..59ece9d 100644 (file)
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -185,4 +185,26 @@ static inline void local_irq_disable(void)
        asm volatile("msr daifset, #3" : : : "memory");
 }
 
+/**
+ * struct arm_smccc_res - Result from SMC/HVC call
+ * @a0-a3 result values from registers 0 to 3
+ */
+struct arm_smccc_res {
+       unsigned long a0;
+       unsigned long a1;
+       unsigned long a2;
+       unsigned long a3;
+};
+
+/**
+ * smccc_hvc - Invoke a SMCCC function using the hvc conduit
+ * @function_id: the SMCCC function to be called
+ * @arg0-arg6: SMCCC function arguments, corresponding to registers x1-x7
+ * @res: pointer to write the return values from registers x0-x3
+ *
+ */
+void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
+              uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
+              uint64_t arg6, struct arm_smccc_res *res);
+
 #endif /* SELFTEST_KVM_PROCESSOR_H */

diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 9343d82..6a04128 100644 (file)
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -500,3 +500,28 @@ void __attribute__((constructor)) init_guest_modes(void)
 {
        guest_modes_append_default();
 }
+
+void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
+              uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
+              uint64_t arg6, struct arm_smccc_res *res)
+{
+       asm volatile("mov   w0, %w[function_id]\n"
+                    "mov   x1, %[arg0]\n"
+                    "mov   x2, %[arg1]\n"
+                    "mov   x3, %[arg2]\n"
+                    "mov   x4, %[arg3]\n"
+                    "mov   x5, %[arg4]\n"
+                    "mov   x6, %[arg5]\n"
+                    "mov   x7, %[arg6]\n"
+                    "hvc   #0\n"
+                    "mov   %[res0], x0\n"
+                    "mov   %[res1], x1\n"
+                    "mov   %[res2], x2\n"
+                    "mov   %[res3], x3\n"
+                    : [res0] "=r"(res->a0), [res1] "=r"(res->a1),
+                      [res2] "=r"(res->a2), [res3] "=r"(res->a3)
+                    : [function_id] "r"(function_id), [arg0] "r"(arg0),
+                      [arg1] "r"(arg1), [arg2] "r"(arg2), [arg3] "r"(arg3),
+                      [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6)
+                    : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7");
+}

diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index 62f2eb9..8c4e811 100644 (file)
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -118,17 +118,10 @@ struct st_time {
 
 static int64_t smccc(uint32_t func, uint64_t arg)
 {
-       unsigned long ret;
+       struct arm_smccc_res res;
 
-       asm volatile(
-               "mov    w0, %w1\n"
-               "mov    x1, %2\n"
-               "hvc    #0\n"
-               "mov    %0, x0\n"
-       : "=r" (ret) : "r" (func), "r" (arg) :
-         "x0", "x1", "x2", "x3");
-
-       return ret;
+       smccc_hvc(func, arg, 0, 0, 0, 0, 0, 0, &res);
+       return res.a0;
 }
 
 static void check_status(struct st_time *st)