linux-kernel - [PATCH v3 07/12] KVM: arm64: selftests: Add support to get the vcpuid from MPIDR

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Message-Id: <20210901211412.4171835-8-rananta@google.com>
Date:   Wed,  1 Sep 2021 21:14:07 +0000
From:   Raghavendra Rao Ananta <rananta@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Peter Shier <pshier@...gle.com>,
        Ricardo Koller <ricarkol@...gle.com>,
        Oliver Upton <oupton@...gle.com>,
        Reiji Watanabe <reijiw@...gle.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        Raghavendra Rao Anata <rananta@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH v3 07/12] KVM: arm64: selftests: Add support to get the vcpuid
 from MPIDR_EL1

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@...gle.com>
---
 .../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