KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.c

Call KVM's (un)register perf callbacks helpers directly from arm.c and
delete perf.c

No functional change intended.
Signed-off-by: NSean Christopherson <seanjc@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211111020738.2512932-17-seanjc@google.com

arch/arm64/include/asm/kvm_host.h

@@ -675,9 +675,6 @@ unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len);
 int kvm_handle_mmio_return(struct kvm_vcpu *vcpu);
 int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa);
 
-void kvm_perf_init(void);
-void kvm_perf_teardown(void);
-
 /*
  * Returns true if a Performance Monitoring Interrupt (PMI), a.k.a. perf event,
  * arrived in guest context.  For arm64, any event that arrives while a vCPU is

arch/arm64/kvm/Makefile

@@ -12,7 +12,7 @@ obj-$(CONFIG_KVM) += hyp/
 
 kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \
 	 $(KVM)/vfio.o $(KVM)/irqchip.o $(KVM)/binary_stats.o \
-	 arm.o mmu.o mmio.o psci.o perf.o hypercalls.o pvtime.o \
+	 arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
 	 inject_fault.o va_layout.o handle_exit.o \
 	 guest.o debug.o reset.o sys_regs.o \
 	 vgic-sys-reg-v3.o fpsimd.o pmu.o \

arch/arm64/kvm/arm.c

@@ -1773,7 +1773,8 @@ static int init_subsystems(void)
 	if (err)
 		goto out;
 
-	kvm_perf_init();
+	kvm_register_perf_callbacks(NULL);
+
 	kvm_sys_reg_table_init();
 
 out:
@@ -2161,7 +2162,7 @@ int kvm_arch_init(void *opaque)
 /* NOP: Compiling as a module not supported */
 void kvm_arch_exit(void)
 {
-	kvm_perf_teardown();
+	kvm_unregister_perf_callbacks();
 }
 
 static int __init early_kvm_mode_cfg(char *arg)

arch/arm64/kvm/perf.c

-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Based on the x86 implementation.
- *
- * Copyright (C) 2012 ARM Ltd.
- * Author: Marc Zyngier <marc.zyngier@arm.com>
- */
-
-#include <linux/perf_event.h>
-#include <linux/kvm_host.h>
-
-#include <asm/kvm_emulate.h>
-
-void kvm_perf_init(void)
-{
-	kvm_register_perf_callbacks(NULL);
-}
-
-void kvm_perf_teardown(void)
-{
-	kvm_unregister_perf_callbacks();
-}