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[07/10] KVM: arm64: selftests: Add support to get the vcpuid from MPIDR_EL1

Message ID 20210813211211.2983293-8-rananta@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: selftests: Introduce arch_timer selftest | expand

Commit Message

Raghavendra Rao Ananta Aug. 13, 2021, 9:12 p.m. UTC 
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@google.com>
---
 .../selftests/kvm/include/aarch64/processor.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
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Patch

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index ae7a079ae180..e9342e63d05d 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -248,4 +248,23 @@  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 */