[PATCH v18 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 | 45 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 485998d20322..a862b5ac15a0 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -52,6 +52,51 @@ static void kvm_pre_enter_guest(struct kvm_vcpu *vcpu)
 	vcpu->arch.aux_inuse &= ~KVM_LARCH_CSR;
 }
 
+/*
+ * 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;
+
+	local_irq_enable();
+	guest_state_exit_irqoff();
+
+	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;
+	}
+
+	cond_resched();
+	local_irq_disable();
+
+	if (ret == RESUME_HOST)
+		return ret;
+
+	/* Only check for signals if not already exiting to userspace */
+	if (signal_pending(current)) {
+		vcpu->run->exit_reason = KVM_EXIT_INTR;
+		++vcpu->stat.signal_exits;
+		return -EINTR;
+	}
+
+	kvm_pre_enter_guest(vcpu);
+	trace_kvm_reenter(vcpu);
+	guest_state_enter_irqoff();
+	return RESUME_GUEST;
+}
+
 int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 {
 	unsigned long timer_hz;
-- 
2.39.1