linux-kernel - [PATCH 2/3] LoongArch: KVM: Implement arch specified functions for guest perf

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Message-Id: <20250224095618.1436016-3-maobibo@loongson.cn>
Date: Mon, 24 Feb 2025 17:56:17 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Tianrui Zhao <zhaotianrui@...ngson.cn>,
	Huacai Chen <chenhuacai@...nel.org>
Cc: WANG Xuerui <kernel@...0n.name>,
	kvm@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] LoongArch: KVM: Implement arch specified functions for guest perf

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

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 arch/loongarch/include/asm/kvm_host.h |  2 ++
 arch/loongarch/kvm/vcpu.c             | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 590982cd986e..49b71ea9c44f 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/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>
@@ -291,6 +292,7 @@ static inline int kvm_get_pmu_num(struct kvm_vcpu_arch *arch)
 
 /* Debug: dump vcpu state */
 int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
+bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu);
 
 /* MMU handling */
 void kvm_flush_tlb_all(void);
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 3318a55a0699..fb85c38f4886 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -361,8 +361,34 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 
 bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 {
+	unsigned long val;
+
+	preempt_disable();
+	val = gcsr_read(LOONGARCH_CSR_CRMD);
+	preempt_enable();
+
+	return (val & CSR_PRMD_PPLV) == 0;
+}
+
+#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)
+{
+	if (vcpu && !(vcpu->arch.aux_inuse & KVM_LARCH_PMU))
+		return true;
+
 	return false;
 }
+#endif
 
 bool kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu)
 {
-- 
2.39.3