[PATCH v3 07/12] KVM: arm64: selftests: Add support to get the vcpuid from MPIDR_EL1

From: Raghavendra Rao Ananta
Date: Wed Sep 01 2021 - 17:14:53 EST


At times, such as when in the interrupt handler, the guest wants to
get the vCPU-id that it's running on. As a result, introduce
get_vcpuid() that parses the MPIDR_EL1 and returns the vcpuid to the
requested caller.

Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
---
.../selftests/kvm/include/aarch64/processor.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index c35bb7b8e870..8b372cd427da 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -251,4 +251,23 @@ static inline void local_irq_disable(void)
asm volatile("msr daifset, #3" : : : "memory");
}

+#define MPIDR_LEVEL_BITS 8
+#define MPIDR_LEVEL_SHIFT(level) (MPIDR_LEVEL_BITS * level)
+#define MPIDR_LEVEL_MASK ((1 << MPIDR_LEVEL_BITS) - 1)
+#define MPIDR_AFFINITY_LEVEL(mpidr, level) \
+ ((mpidr >> MPIDR_LEVEL_SHIFT(level)) & MPIDR_LEVEL_MASK)
+
+static inline uint32_t get_vcpuid(void)
+{
+ uint32_t vcpuid = 0;
+ uint64_t mpidr = read_sysreg(mpidr_el1);
+
+ /* KVM limits only 16 vCPUs at level 0 */
+ vcpuid = mpidr & 0x0f;
+ vcpuid |= MPIDR_AFFINITY_LEVEL(mpidr, 1) << 4;
+ vcpuid |= MPIDR_AFFINITY_LEVEL(mpidr, 2) << 12;
+
+ return vcpuid;
+}
+
#endif /* SELFTEST_KVM_PROCESSOR_H */
--
2.33.0.153.gba50c8fa24-goog