[PATCH v5 16/44] KVM: Add a simplified wrapper for registering perf callbacks

Sean Christopherson
2025-08-06T19:57:58Z

Add a parameter-less API for registering perf callbacks in anticipation of
introducing another x86-only parameter for handling mediated PMU PMIs.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/arm64/kvm/arm.c | 2 +-
arch/loongarch/kvm/main.c | 2 +-
arch/riscv/kvm/main.c | 2 +-
arch/x86/kvm/x86.c | 2 +-
include/linux/kvm_host.h | 11 +++++++++--
virt/kvm/kvm_main.c | 5 +++--
6 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 888f7c7abf54..6c604b5214f2 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2328,7 +2328,7 @@ static int __init init_subsystems(void)
if (err)
goto out;

- kvm_register_perf_callbacks(NULL);
+ kvm_register_perf_callbacks();

out:
if (err)
diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
index 80ea63d465b8..f62326fe29fa 100644
--- a/arch/loongarch/kvm/main.c
+++ b/arch/loongarch/kvm/main.c
@@ -394,7 +394,7 @@ static int kvm_loongarch_env_init(void)
}

kvm_init_gcsr_flag();
- kvm_register_perf_callbacks(NULL);
+ kvm_register_perf_callbacks();

/* Register LoongArch IPI interrupt controller interface. */
ret = kvm_loongarch_register_ipi_device();
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index 67c876de74ef..cbe842c2f615 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -159,7 +159,7 @@ static int __init riscv_kvm_init(void)
kvm_info("AIA available with %d guest external interrupts\n",
kvm_riscv_aia_nr_hgei);

- kvm_register_perf_callbacks(NULL);
+ kvm_register_perf_callbacks();

rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
if (rc) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5af2c5aed0f2..d80bbd5e0859 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9689,7 +9689,7 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
set_hv_tscchange_cb(kvm_hyperv_tsc_notifier);
#endif

- kvm_register_perf_callbacks(ops->handle_intel_pt_intr);
+ __kvm_register_perf_callbacks(ops->handle_intel_pt_intr, NULL);

if (IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) && tdp_mmu_enabled)
kvm_caps.supported_vm_types |= BIT(KVM_X86_SW_PROTECTED_VM);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 15656b7fba6c..20c50eaa0089 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1731,10 +1731,17 @@ static inline bool kvm_arch_intc_initialized(struct kvm *kvm)
#ifdef CONFIG_GUEST_PERF_EVENTS
unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu);

-void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void));
+void __kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void),
+ void (*mediated_pmi_handler)(void));
+
+static inline void kvm_register_perf_callbacks(void)
+{
+ __kvm_register_perf_callbacks(NULL, NULL);
+}
+
void kvm_unregister_perf_callbacks(void);
#else
-static inline void kvm_register_perf_callbacks(void *ign) {}
+static inline void kvm_register_perf_callbacks(void) {}
static inline void kvm_unregister_perf_callbacks(void) {}
#endif /* CONFIG_GUEST_PERF_EVENTS */

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ecafab2e17d9..d477a7fda0ae 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -6429,10 +6429,11 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
.handle_mediated_pmi = NULL,
};

-void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void))
+void __kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void),
+ void (*mediated_pmi_handler)(void))
{
kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler;
- kvm_guest_cbs.handle_mediated_pmi = NULL;
+ kvm_guest_cbs.handle_mediated_pmi = mediated_pmi_handler;

perf_register_guest_info_callbacks(&kvm_guest_cbs);
}
--
2.50.1.565.gc32cd1483b-goog