[PATCH v7 10/15] KVM: arm64: selftests: Add guest support to get the vcpuid

[Raghavendra Rao Ananta]

At times, such as when in the interrupt handler, the guest wants
to get the vcpuid that it's running on to pull the per-cpu private
data. As a result, introduce guest_get_vcpuid() that returns the
vcpuid of the calling vcpu. The interface is architecture
independent, but defined only for arm64 as of now.

Suggested-by: Reiji Watanabe <reijiw at google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta at google.com>
Reviewed-by: Ricardo Koller <ricarkol at google.com>
Reviewed-by: Reiji Watanabe <reijiw at google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h      | 2 ++
 tools/testing/selftests/kvm/lib/aarch64/processor.c | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 010b59b13917..bcf05f5381ed 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -400,4 +400,6 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
 int vm_get_stats_fd(struct kvm_vm *vm);
 int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
 
+uint32_t guest_get_vcpuid(void);
+
 #endif /* SELFTEST_KVM_UTIL_H */
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 34f6bd47661f..b4eeeafd2a70 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -277,6 +277,7 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_vcpu_init
 	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TCR_EL1), tcr_el1);
 	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_MAIR_EL1), DEFAULT_MAIR_EL1);
 	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TTBR0_EL1), vm->pgd);
+	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TPIDR_EL1), vcpuid);
 }
 
 void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
@@ -426,3 +427,8 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
 	assert(vector < VECTOR_NUM);
 	handlers->exception_handlers[vector][0] = handler;
 }
+
+uint32_t guest_get_vcpuid(void)
+{
+	return read_sysreg(tpidr_el1);
+}
-- 
2.33.0.309.g3052b89438-goog