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From: Xiong Zhang <xiong.y.zhang@linux.intel.com>
To: seanjc@google.com,
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	peterz@infradead.org,
	mizhang@google.com,
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	xiong.y.zhang@linux.intel.com,
	Xiong Zhang <xiong.y.zhang@intel.com>
Subject: [RFC PATCH 05/41] KVM: x86/pmu: Register PMI handler for passthrough PMU
Date: Fri, 26 Jan 2024 16:54:08 +0800
Message-Id: <20240126085444.324918-6-xiong.y.zhang@linux.intel.com>
In-Reply-To: <20240126085444.324918-1-xiong.y.zhang@linux.intel.com>
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From: Xiong Zhang <xiong.y.zhang@intel.com>

Add function to register/unregister PMI handler at KVM module
initialization and destroy time. This allows the host PMU with passthough
capability enabled switch PMI handler at PMU context switch time.

Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 arch/x86/kvm/x86.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2c924075f6f1..4432e736129f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10611,6 +10611,18 @@ void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(__kvm_request_immediate_exit);
 
+void kvm_passthrough_pmu_handler(void)
+{
+	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
+
+	if (!vcpu) {
+		pr_warn_once("%s: no running vcpu found!\n", __func__);
+		return;
+	}
+
+	kvm_make_request(KVM_REQ_PMI, vcpu);
+}
+
 /*
  * Called within kvm->srcu read side.
  * Returns 1 to let vcpu_run() continue the guest execution loop without
@@ -13815,6 +13827,7 @@ static int __init kvm_x86_init(void)
 {
 	kvm_mmu_x86_module_init();
 	mitigate_smt_rsb &= boot_cpu_has_bug(X86_BUG_SMT_RSB) && cpu_smt_possible();
+	kvm_set_vpmu_handler(kvm_passthrough_pmu_handler);
 	return 0;
 }
 module_init(kvm_x86_init);
@@ -13825,5 +13838,6 @@ static void __exit kvm_x86_exit(void)
 	 * If module_init() is implemented, module_exit() must also be
 	 * implemented to allow module unload.
 	 */
+	kvm_set_vpmu_handler(NULL);
 }
 module_exit(kvm_x86_exit);
-- 
2.34.1