[PATCH v19 08/30] LoongArch: KVM: Implement vcpu handle exit interface

[Tianrui Zhao]

Implement vcpu handle exit interface, getting the exit code by ESTAT
register and using kvm exception vector to handle it.

Reviewed-by: Bibo Mao <maobibo@xxxxxxxxxxx>
Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
 arch/loongarch/kvm/vcpu.c | 41 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 83f2988ea67b..ca4e8d074e6c 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -103,6 +103,47 @@ static int kvm_pre_enter_guest(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+/*
+ * Return 1 for resume guest and "<= 0" for resume host.
+ */
+static int _kvm_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+	unsigned long exst = vcpu->arch.host_estat;
+	u32 intr = exst & 0x1fff; /* ignore NMI */
+	u32 exccode = (exst & CSR_ESTAT_EXC) >> CSR_ESTAT_EXC_SHIFT;
+	int ret = RESUME_GUEST;
+
+	vcpu->mode = OUTSIDE_GUEST_MODE;
+
+	/* Set a default exit reason */
+	run->exit_reason = KVM_EXIT_UNKNOWN;
+
+	guest_timing_exit_irqoff();
+	guest_state_exit_irqoff();
+	local_irq_enable();
+
+	trace_kvm_exit(vcpu, exccode);
+	if (exccode) {
+		ret = _kvm_handle_fault(vcpu, exccode);
+	} else {
+		WARN(!intr, "vm exiting with suspicious irq\n");
+		++vcpu->stat.int_exits;
+	}
+
+	if (ret == RESUME_GUEST)
+		ret = kvm_pre_enter_guest(vcpu);
+
+	if (ret != RESUME_GUEST) {
+		local_irq_disable();
+		return ret;
+	}
+
+	guest_timing_enter_irqoff();
+	guest_state_enter_irqoff();
+	trace_kvm_reenter(vcpu);
+	return RESUME_GUEST;
+}
+
 int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 {
 	unsigned long timer_hz;
-- 
2.39.1