[PATCH v5 05/14] KVM: arm64: selftests: Add support for cpu_relax

Raghavendra Rao Ananta
2021-09-13T20:50:27Z

Implement the guest helper routine, cpu_relax(), to yield
the processor to other tasks.

The function was derived from
arch/arm64/include/asm/vdso/processor.h.

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/include/aarch64/processor.h | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 93797783abad..265054c24481 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -122,6 +122,11 @@ void vm_install_exception_handler(struct kvm_vm *vm,
void vm_install_sync_handler(struct kvm_vm *vm,
int vector, int ec, handler_fn handler);

+static inline void cpu_relax(void)
+{
+ asm volatile("yield" ::: "memory");
+}
+
#define isb() asm volatile("isb" : : : "memory")
#define dsb(opt) asm volatile("dsb " #opt : : : "memory")
#define dmb(opt) asm volatile("dmb " #opt : : : "memory")
--
2.33.0.309.g3052b89438-goog