KVM: arm64: selftests: Add guest support to get the vcpuid

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 <[email protected]>
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Ricardo Koller <[email protected]>
Reviewed-by: Reiji Watanabe <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 files changed, 6 insertions, 0 deletions

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);
+}