[PATCH 1/9] KVM: arm64: selftests: Add helpers to extract a field of an ID register

[Reiji Watanabe]

Introduce helpers to extract a field of an ID register.
Subsequent patches will use those helpers.

Signed-off-by: Reiji Watanabe <reijiw at google.com>
---
 .../selftests/kvm/include/aarch64/processor.h     |  2 ++
 .../testing/selftests/kvm/lib/aarch64/processor.c | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index a8124f9dd68a..a9b4b4e0e592 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -193,4 +193,6 @@ void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
 
 uint32_t guest_get_vcpuid(void);
 
+int cpuid_get_sfield(uint64_t val, int field_shift);
+unsigned int cpuid_get_ufield(uint64_t val, int field_shift);
 #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 6f5551368944..0b2ad46e7ff5 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -528,3 +528,18 @@ void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
 		       [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6)
 		     : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7");
 }
+
+/* Helpers to get a signed/unsigned feature field from ID register value */
+int cpuid_get_sfield(uint64_t val, int field_shift)
+{
+	int width = 4;
+
+	return (int64_t)(val << (64 - width - field_shift)) >> (64 - width);
+}
+
+unsigned int cpuid_get_ufield(uint64_t val, int field_shift)
+{
+	int width = 4;
+
+	return (uint64_t)(val << (64 - width - field_shift)) >> (64 - width);
+}
-- 
2.37.1.595.g718a3a8f04-goog