LoongArch: KVM: Implement arch-specific functions for guest perf

Three architecture specific functions are added for the guest perf
feature, they are kvm_arch_vcpu_in_kernel(), kvm_arch_vcpu_get_ip()
and kvm_arch_pmi_in_guest().

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: bibo-mao

arch/loongarch/include/asm/kvm_host.h

@@ -12,6 +12,7 @@
 #include <linux/kvm.h>
 #include <linux/kvm_types.h>
 #include <linux/mutex.h>
+#include <linux/perf_event.h>
 #include <linux/spinlock.h>
 #include <linux/threads.h>
 #include <linux/types.h>
@@ -292,6 +293,8 @@ static inline int kvm_get_pmu_num(struct kvm_vcpu_arch *arch)
 	return (arch->cpucfg[6] & CPUCFG6_PMNUM) >> CPUCFG6_PMNUM_SHIFT;
 }
 
+bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu);
+
 /* Debug: dump vcpu state */
 int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
 

arch/loongarch/kvm/vcpu.c

@@ -361,9 +361,32 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 
 bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 {
-	return false;
+	unsigned long val;
+
+	preempt_disable();
+	val = gcsr_read(LOONGARCH_CSR_CRMD);
+	preempt_enable();
+
+	return (val & CSR_PRMD_PPLV) == PLV_KERN;
 }
 
+#ifdef CONFIG_GUEST_PERF_EVENTS
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.pc;
+}
+
+/*
+ * Returns true if a Performance Monitoring Interrupt (PMI), a.k.a. perf event,
+ * arrived in guest context.  For LoongArch64, if PMU is not passthrough to VM,
+ * any event that arrives while a vCPU is loaded is considered to be "in guest".
+ */
+bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+	return (vcpu && !(vcpu->arch.aux_inuse & KVM_LARCH_PMU));
+}
+#endif
+
 bool kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu)
 {
 	return false;