[PATCH v18 22/30] LoongArch: KVM: Implement handle idle exception

From: Tianrui Zhao
Date: Wed Aug 02 2023 - 22:25:38 EST


Implement kvm handle LoongArch vcpu idle exception, using kvm_vcpu_block
to emulate it.

Reviewed-by: Bibo Mao <maobibo@xxxxxxxxxxx>
Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
arch/loongarch/kvm/exit.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index 32edd915ebcb..30748238c78c 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -188,3 +188,23 @@ int _kvm_complete_iocsr_read(struct kvm_vcpu *vcpu, struct kvm_run *run)

return er;
}
+
+int _kvm_emu_idle(struct kvm_vcpu *vcpu)
+{
+ ++vcpu->stat.idle_exits;
+ trace_kvm_exit_idle(vcpu, KVM_TRACE_EXIT_IDLE);
+
+ if (!kvm_arch_vcpu_runnable(vcpu)) {
+ /*
+ * Switch to the software timer before halt-polling/blocking as
+ * the guest's timer may be a break event for the vCPU, and the
+ * hypervisor timer runs only when the CPU is in guest mode.
+ * Switch before halt-polling so that KVM recognizes an expired
+ * timer before blocking.
+ */
+ kvm_save_timer(vcpu);
+ kvm_vcpu_block(vcpu);
+ }
+
+ return EMULATE_DONE;
+}
--
2.39.1