[PATCH v5 10/14] KVM: arm64: selftests: Add light-weight spinlock support

Raghavendra Rao Ananta
2021-09-13T20:51:21Z

Add a simpler version of spinlock support for ARM64 for
the guests to use.

The implementation is loosely based on the spinlock
implementation in kvm-unit-tests.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
tools/testing/selftests/kvm/Makefile | 2 +-
.../selftests/kvm/include/aarch64/spinlock.h | 13 +++++++++
.../selftests/kvm/lib/aarch64/spinlock.c | 27 +++++++++++++++++++
3 files changed, 41 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/kvm/include/aarch64/spinlock.h
create mode 100644 tools/testing/selftests/kvm/lib/aarch64/spinlock.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 5d05801ab816..61f0d376af99 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -35,7 +35,7 @@ endif

LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/rbtree.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c
LIBKVM_x86_64 = lib/x86_64/apic.c lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S
-LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S
+LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S lib/aarch64/spinlock.c
LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c

TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test
diff --git a/tools/testing/selftests/kvm/include/aarch64/spinlock.h b/tools/testing/selftests/kvm/include/aarch64/spinlock.h
new file mode 100644
index 000000000000..cf0984106d14
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/aarch64/spinlock.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef SELFTEST_KVM_ARM64_SPINLOCK_H
+#define SELFTEST_KVM_ARM64_SPINLOCK_H
+
+struct spinlock {
+ int v;
+};
+
+extern void spin_lock(struct spinlock *lock);
+extern void spin_unlock(struct spinlock *lock);
+
+#endif /* SELFTEST_KVM_ARM64_SPINLOCK_H */
diff --git a/tools/testing/selftests/kvm/lib/aarch64/spinlock.c b/tools/testing/selftests/kvm/lib/aarch64/spinlock.c
new file mode 100644
index 000000000000..a076e780be5d
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/aarch64/spinlock.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ARM64 Spinlock support
+ */
+#include <stdint.h>
+
+#include "spinlock.h"
+
+void spin_lock(struct spinlock *lock)
+{
+ int val, res;
+
+ asm volatile(
+ "1: ldaxr %w0, [%2]\n"
+ " cbnz %w0, 1b\n"
+ " mov %w0, #1\n"
+ " stxr %w1, %w0, [%2]\n"
+ " cbnz %w1, 1b\n"
+ : "=&r" (val), "=&r" (res)
+ : "r" (&lock->v)
+ : "memory");
+}
+
+void spin_unlock(struct spinlock *lock)
+{
+ asm volatile("stlr wzr, [%0]\n" : : "r" (&lock->v) : "memory");
+}
--
2.33.0.309.g3052b89438-goog