x86: Restrict KVM-induced symbol exports to KVM modules where obvious/possible

Extend KVM's export macro framework to provide EXPORT_SYMBOL_FOR_KVM(),
and use the helper macro to export symbols for KVM throughout x86 if and
only if KVM will build one or more modules, and only for those modules.

To avoid unnecessary exports when CONFIG_KVM=m but kvm.ko will not be
built (because no vendor modules are selected), let arch code #define
EXPORT_SYMBOL_FOR_KVM to suppress/override the exports.

Note, the set of symbols to restrict to KVM was generated by manual search
and audit; any "misses" are due to human error, not some grand plan.

Signed-off-by: Sean Christopherson <[e-mail]>
Signed-off-by: Dave Hansen <[e-mail]>
Acked-by: Kai Huang <[e-mail]>
Tested-by: Kai Huang <[e-mail]>
Link: https://patch.msgid.link/20251112173944.1380633-5-seanjc%40google.com

arch/x86/entry/entry.S

···
  */
 
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 #include <linux/linkage.h>
 #include <linux/objtool.h>
 #include <asm/msr-index.h>
···
 	FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET
 	RET
 SYM_FUNC_END(write_ibpb)
-/* For KVM */
-EXPORT_SYMBOL_GPL(write_ibpb);
+EXPORT_SYMBOL_FOR_KVM(write_ibpb);
 
 .popsection
 
···
 	.word __KERNEL_DS
 .align L1_CACHE_BYTES, 0xcc
 SYM_CODE_END(x86_verw_sel);
-/* For KVM */
-EXPORT_SYMBOL_GPL(x86_verw_sel);
+EXPORT_SYMBOL_FOR_KVM(x86_verw_sel);
 
 .popsection
 

arch/x86/entry/entry_64.S

···
  * - idtentry:		Define exception entry points.
  */
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 #include <linux/linkage.h>
 #include <asm/segment.h>
 #include <asm/cache.h>
···
 	pop	%rbp
 	RET
 SYM_FUNC_END(clear_bhb_loop)
-EXPORT_SYMBOL_GPL(clear_bhb_loop)
+EXPORT_SYMBOL_FOR_KVM(clear_bhb_loop)
 STACK_FRAME_NON_STANDARD(clear_bhb_loop)

arch/x86/entry/entry_64_fred.S

···
  */
 
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 
 #include <asm/asm.h>
 #include <asm/fred.h>
···
 	RET
 
 SYM_FUNC_END(asm_fred_entry_from_kvm)
-EXPORT_SYMBOL_GPL(asm_fred_entry_from_kvm);
+EXPORT_SYMBOL_FOR_KVM(asm_fred_entry_from_kvm);
 #endif

arch/x86/events/amd/core.c

···
 #include <linux/perf_event.h>
 #include <linux/jump_label.h>
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/slab.h>
···
 	/* Reload all events */
 	amd_pmu_reload_virt();
 }
-EXPORT_SYMBOL_GPL(amd_pmu_enable_virt);
+EXPORT_SYMBOL_FOR_KVM(amd_pmu_enable_virt);
 
 void amd_pmu_disable_virt(void)
 {
···
 	/* Reload all events */
 	amd_pmu_reload_virt();
 }
-EXPORT_SYMBOL_GPL(amd_pmu_disable_virt);
+EXPORT_SYMBOL_FOR_KVM(amd_pmu_disable_virt);

arch/x86/events/core.c

···
 #include <linux/export.h>
 #include <linux/init.h>
 #include <linux/kdebug.h>
+#include <linux/kvm_types.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/clock.h>
 #include <linux/uaccess.h>
···
 {
 	return static_call(x86_pmu_guest_get_msrs)(nr, data);
 }
-EXPORT_SYMBOL_GPL(perf_guest_get_msrs);
+EXPORT_SYMBOL_FOR_KVM(perf_guest_get_msrs);
 
 /*
  * There may be PMI landing after enabled=0. The PMI hitting could be before or
···
 	cap->events_mask_len	= x86_pmu.events_mask_len;
 	cap->pebs_ept		= x86_pmu.pebs_ept;
 }
-EXPORT_SYMBOL_GPL(perf_get_x86_pmu_capability);
+EXPORT_SYMBOL_FOR_KVM(perf_get_x86_pmu_capability);
 
 u64 perf_get_hw_event_config(int hw_event)
 {
···
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(perf_get_hw_event_config);
+EXPORT_SYMBOL_FOR_KVM(perf_get_hw_event_config);

arch/x86/events/intel/lbr.c

···
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/kvm_types.h>
 #include <linux/perf_event.h>
 #include <linux/types.h>
 
···
 	lbr->info = x86_pmu.lbr_info;
 	lbr->has_callstack = x86_pmu_has_lbr_callstack();
 }
-EXPORT_SYMBOL_GPL(x86_perf_get_lbr);
+EXPORT_SYMBOL_FOR_KVM(x86_perf_get_lbr);
 
 struct event_constraint vlbr_constraint =
 	__EVENT_CONSTRAINT(INTEL_FIXED_VLBR_EVENT, (1ULL << INTEL_PMC_IDX_FIXED_VLBR),

arch/x86/events/intel/pt.c

···
 #include <linux/limits.h>
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <linux/kvm_types.h>
 
 #include <asm/cpuid/api.h>
 #include <asm/perf_event.h>
···
 
 	return (c & cd->mask) >> shift;
 }
-EXPORT_SYMBOL_GPL(intel_pt_validate_cap);
+EXPORT_SYMBOL_FOR_KVM(intel_pt_validate_cap);
 
 u32 intel_pt_validate_hw_cap(enum pt_capabilities cap)
 {
 	return intel_pt_validate_cap(pt_pmu.caps, cap);
 }
-EXPORT_SYMBOL_GPL(intel_pt_validate_hw_cap);
+EXPORT_SYMBOL_FOR_KVM(intel_pt_validate_hw_cap);
 
 static ssize_t pt_cap_show(struct device *cdev,
 			   struct device_attribute *attr,
···
 
 	local_irq_restore(flags);
 }
-EXPORT_SYMBOL_GPL(intel_pt_handle_vmx);
+EXPORT_SYMBOL_FOR_KVM(intel_pt_handle_vmx);
 
 /*
  * PMU callbacks

arch/x86/include/asm/kvm_types.h

···
 #define KVM_SUB_MODULES kvm-intel
 #else
 #undef KVM_SUB_MODULES
+/*
+ * Don't export symbols for KVM without vendor modules, as kvm.ko is built iff
+ * at least one vendor module is enabled.
+ */
+#define EXPORT_SYMBOL_FOR_KVM(symbol)
 #endif
 
 #define KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE 40

arch/x86/kernel/apic/apic.c

···
 #include <linux/dmi.h>
 #include <linux/smp.h>
 #include <linux/mm.h>
+#include <linux/kvm_types.h>
 
 #include <xen/xen.h>
 
···
 		dest |= msg->arch_addr_hi.destid_8_31 << 8;
 	return dest;
 }
-EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid);
+EXPORT_SYMBOL_FOR_KVM(x86_msi_msg_get_destid);
 
 static void __init apic_bsp_up_setup(void)
 {

arch/x86/kernel/apic/apic_common.c

···
  * SPDX-License-Identifier: GPL-2.0
  */
 #include <linux/irq.h>
+#include <linux/kvm_types.h>
 #include <asm/apic.h>
 
 #include "local.h"
···
 	else
 		return BAD_APICID;
 }
-EXPORT_SYMBOL_GPL(default_cpu_present_to_apicid);
+EXPORT_SYMBOL_FOR_KVM(default_cpu_present_to_apicid);
 
 /*
  * Set up the logical destination ID when the APIC operates in logical

arch/x86/kernel/cpu/amd.c

···
 #include <linux/bitops.h>
 #include <linux/elf.h>
 #include <linux/mm.h>
-
+#include <linux/kvm_types.h>
 #include <linux/io.h>
 #include <linux/sched.h>
 #include <linux/sched/clock.h>
···
 
 	return per_cpu(amd_dr_addr_mask[dr], smp_processor_id());
 }
-EXPORT_SYMBOL_GPL(amd_get_dr_addr_mask);
+EXPORT_SYMBOL_FOR_KVM(amd_get_dr_addr_mask);
 
 static void zenbleed_check_cpu(void *unused)
 {

arch/x86/kernel/cpu/bugs.c

···
 #include <linux/sched/smt.h>
 #include <linux/pgtable.h>
 #include <linux/bpf.h>
+#include <linux/kvm_types.h>
 
 #include <asm/spec-ctrl.h>
 #include <asm/cmdline.h>
···
 
 /* Control IBPB on vCPU load */
 DEFINE_STATIC_KEY_FALSE(switch_vcpu_ibpb);
-EXPORT_SYMBOL_GPL(switch_vcpu_ibpb);
+EXPORT_SYMBOL_FOR_KVM(switch_vcpu_ibpb);
 
 /* Control CPU buffer clear before idling (halt, mwait) */
 DEFINE_STATIC_KEY_FALSE(cpu_buf_idle_clear);
···
  * mitigation is required.
  */
 DEFINE_STATIC_KEY_FALSE(cpu_buf_vm_clear);
-EXPORT_SYMBOL_GPL(cpu_buf_vm_clear);
+EXPORT_SYMBOL_FOR_KVM(cpu_buf_vm_clear);
 
 #undef pr_fmt
 #define pr_fmt(fmt)	"mitigations: " fmt
···
 		speculation_ctrl_update(tif);
 	}
 }
-EXPORT_SYMBOL_GPL(x86_virt_spec_ctrl);
+EXPORT_SYMBOL_FOR_KVM(x86_virt_spec_ctrl);
 
 static void x86_amd_ssb_disable(void)
 {
···
 	return (gds_mitigation == GDS_MITIGATION_FULL ||
 		gds_mitigation == GDS_MITIGATION_FULL_LOCKED);
 }
-EXPORT_SYMBOL_GPL(gds_ucode_mitigated);
+EXPORT_SYMBOL_FOR_KVM(gds_ucode_mitigated);
 
 void update_gds_msr(void)
 {
···
 }
 
 bool itlb_multihit_kvm_mitigation;
-EXPORT_SYMBOL_GPL(itlb_multihit_kvm_mitigation);
+EXPORT_SYMBOL_FOR_KVM(itlb_multihit_kvm_mitigation);
 
 #undef pr_fmt
 #define pr_fmt(fmt)	"L1TF: " fmt
···
 /* Default mitigation for L1TF-affected CPUs */
 enum l1tf_mitigations l1tf_mitigation __ro_after_init =
 	IS_ENABLED(CONFIG_MITIGATION_L1TF) ? L1TF_MITIGATION_AUTO : L1TF_MITIGATION_OFF;
-#if IS_ENABLED(CONFIG_KVM_INTEL)
-EXPORT_SYMBOL_GPL(l1tf_mitigation);
-#endif
+EXPORT_SYMBOL_FOR_KVM(l1tf_mitigation);
 enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
-EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation);
+EXPORT_SYMBOL_FOR_KVM(l1tf_vmx_mitigation);
 
 /*
  * These CPUs all support 44bits physical address space internally in the

arch/x86/kernel/cpu/bus_lock.c

···
 #include <linux/workqueue.h>
 #include <linux/delay.h>
 #include <linux/cpuhotplug.h>
+#include <linux/kvm_types.h>
 #include <asm/cpu_device_id.h>
 #include <asm/cmdline.h>
 #include <asm/traps.h>
···
 	force_sig_fault(SIGBUS, BUS_ADRALN, NULL);
 	return false;
 }
-EXPORT_SYMBOL_GPL(handle_guest_split_lock);
+EXPORT_SYMBOL_FOR_KVM(handle_guest_split_lock);
 
 void bus_lock_init(void)
 {

arch/x86/kernel/cpu/common.c

···
 #include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 #include <linux/percpu.h>
 #include <linux/string.h>
 #include <linux/ctype.h>
···
 		__write_cr4(newval);
 	}
 }
-EXPORT_SYMBOL(cr4_update_irqsoff);
+EXPORT_SYMBOL_FOR_KVM(cr4_update_irqsoff);
 
 /* Read the CR4 shadow. */
 unsigned long cr4_read_shadow(void)
 {
 	return this_cpu_read(cpu_tlbstate.cr4);
 }
-EXPORT_SYMBOL_GPL(cr4_read_shadow);
+EXPORT_SYMBOL_FOR_KVM(cr4_read_shadow);
 
 void cr4_init(void)
 {
···
 	gdt_descr.size = GDT_SIZE - 1;
 	load_gdt(&gdt_descr);
 }
-EXPORT_SYMBOL_GPL(load_direct_gdt);
+EXPORT_SYMBOL_FOR_KVM(load_direct_gdt);
 
 /* Load a fixmap remapping of the per-cpu GDT */
 void load_fixmap_gdt(int cpu)

arch/x86/kernel/cpu/sgx/main.c

···
 #include <linux/freezer.h>
 #include <linux/highmem.h>
 #include <linux/kthread.h>
+#include <linux/kvm_types.h>
 #include <linux/miscdevice.h>
 #include <linux/node.h>
 #include <linux/pagemap.h>
···
 	*allowed_attributes |= SGX_ATTR_PROVISIONKEY;
 	return 0;
 }
-EXPORT_SYMBOL_GPL(sgx_set_attribute);
+EXPORT_SYMBOL_FOR_KVM(sgx_set_attribute);
 
 static int __init sgx_init(void)
 {

arch/x86/kernel/cpu/sgx/virt.c

···
  * Copyright(c) 2021 Intel Corporation.
  */
 
+#include <linux/kvm_types.h>
 #include <linux/miscdevice.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
···
 	WARN_ON_ONCE(ret);
 	return 0;
 }
-EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
+EXPORT_SYMBOL_FOR_KVM(sgx_virt_ecreate);
 
 static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
 			    void __user *secs)
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(sgx_virt_einit);
+EXPORT_SYMBOL_FOR_KVM(sgx_virt_einit);

arch/x86/kernel/e820.c

···
 #include <linux/firmware-map.h>
 #include <linux/sort.h>
 #include <linux/memory_hotplug.h>
+#include <linux/kvm_types.h>
 
 #include <asm/e820/api.h>
 #include <asm/setup.h>
···
 {
 	return _e820__mapped_any(e820_table_firmware, start, end, type);
 }
-EXPORT_SYMBOL_GPL(e820__mapped_raw_any);
+EXPORT_SYMBOL_FOR_KVM(e820__mapped_raw_any);
 
 bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
 {

arch/x86/kernel/fpu/core.c

···
 #include <uapi/asm/kvm.h>
 
 #include <linux/hardirq.h>
+#include <linux/kvm_types.h>
 #include <linux/pkeys.h>
 #include <linux/vmalloc.h>
 
···
 
 	return true;
 }
-EXPORT_SYMBOL_GPL(fpu_alloc_guest_fpstate);
+EXPORT_SYMBOL_FOR_KVM(fpu_alloc_guest_fpstate);
 
 void fpu_free_guest_fpstate(struct fpu_guest *gfpu)
 {
···
 	gfpu->fpstate = NULL;
 	vfree(fpstate);
 }
-EXPORT_SYMBOL_GPL(fpu_free_guest_fpstate);
+EXPORT_SYMBOL_FOR_KVM(fpu_free_guest_fpstate);
 
 /*
   * fpu_enable_guest_xfd_features - Check xfeatures against guest perm and enable
···
 
 	return __xfd_enable_feature(xfeatures, guest_fpu);
 }
-EXPORT_SYMBOL_GPL(fpu_enable_guest_xfd_features);
+EXPORT_SYMBOL_FOR_KVM(fpu_enable_guest_xfd_features);
 
 #ifdef CONFIG_X86_64
 void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd)
···
 		xfd_update_state(guest_fpu->fpstate);
 	fpregs_unlock();
 }
-EXPORT_SYMBOL_GPL(fpu_update_guest_xfd);
+EXPORT_SYMBOL_FOR_KVM(fpu_update_guest_xfd);
 
 /**
  * fpu_sync_guest_vmexit_xfd_state - Synchronize XFD MSR and software state
···
 		__this_cpu_write(xfd_state, fpstate->xfd);
 	}
 }
-EXPORT_SYMBOL_GPL(fpu_sync_guest_vmexit_xfd_state);
+EXPORT_SYMBOL_FOR_KVM(fpu_sync_guest_vmexit_xfd_state);
 #endif /* CONFIG_X86_64 */
 
 int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest)
···
 	fpregs_unlock();
 	return 0;
 }
-EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpstate);
+EXPORT_SYMBOL_FOR_KVM(fpu_swap_kvm_fpstate);
 
 void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf,
 				    unsigned int size, u64 xfeatures, u32 pkru)
···
 		ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE;
 	}
 }
-EXPORT_SYMBOL_GPL(fpu_copy_guest_fpstate_to_uabi);
+EXPORT_SYMBOL_FOR_KVM(fpu_copy_guest_fpstate_to_uabi);
 
 int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf,
 				   u64 xcr0, u32 *vpkru)
···
 
 	return copy_uabi_from_kernel_to_xstate(kstate, ustate, vpkru);
 }
-EXPORT_SYMBOL_GPL(fpu_copy_uabi_to_guest_fpstate);
+EXPORT_SYMBOL_FOR_KVM(fpu_copy_uabi_to_guest_fpstate);
 #endif /* CONFIG_KVM */
 
 void kernel_fpu_begin_mask(unsigned int kfpu_mask)
···
 
 	fpregs_restore_userregs();
 }
-EXPORT_SYMBOL_GPL(switch_fpu_return);
+EXPORT_SYMBOL_FOR_KVM(switch_fpu_return);
 
 void fpregs_lock_and_load(void)
 {
···
 
 	WARN_ON_FPU(!fpregs_state_valid(fpu, smp_processor_id()));
 }
-EXPORT_SYMBOL_GPL(fpregs_assert_state_consistent);
+EXPORT_SYMBOL_FOR_KVM(fpregs_assert_state_consistent);
 #endif
 
 void fpregs_mark_activate(void)

arch/x86/kernel/fpu/xstate.c

···
 #include <linux/compat.h>
 #include <linux/cpu.h>
 #include <linux/mman.h>
+#include <linux/kvm_types.h>
 #include <linux/nospec.h>
 #include <linux/pkeys.h>
 #include <linux/seq_file.h>
···
 
 	return __raw_xsave_addr(xsave, xfeature_nr);
 }
-EXPORT_SYMBOL_GPL(get_xsave_addr);
+EXPORT_SYMBOL_FOR_KVM(get_xsave_addr);
 
 /*
  * Given an xstate feature nr, calculate where in the xsave buffer the state is.
···
 	if (addr)
 		memset(addr, 0, xstate_sizes[xfeature]);
 }
-EXPORT_SYMBOL_GPL(fpstate_clear_xstate_component);
+EXPORT_SYMBOL_FOR_KVM(fpstate_clear_xstate_component);
 #endif
 
 #ifdef CONFIG_X86_64
···
 {
 	return xstate_get_group_perm(true);
 }
-EXPORT_SYMBOL_GPL(xstate_get_guest_group_perm);
+EXPORT_SYMBOL_FOR_KVM(xstate_get_guest_group_perm);
 
 /**
  * fpu_xstate_prctl - xstate permission operations

arch/x86/kernel/hw_breakpoint.c

···
 #include <linux/percpu.h>
 #include <linux/kdebug.h>
 #include <linux/kernel.h>
+#include <linux/kvm_types.h>
 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
···
 	set_debugreg(DR6_RESERVED, 6);
 	set_debugreg(__this_cpu_read(cpu_dr7), 7);
 }
-EXPORT_SYMBOL_GPL(hw_breakpoint_restore);
+EXPORT_SYMBOL_FOR_KVM(hw_breakpoint_restore);
 
 /*
  * Handle debug exception notifications.

arch/x86/kernel/irq.c

···
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/irq.h>
+#include <linux/kvm_types.h>
 
 #include <asm/irq_stack.h>
 #include <asm/apic.h>
···
 		synchronize_rcu();
 	}
 }
-EXPORT_SYMBOL_GPL(kvm_set_posted_intr_wakeup_handler);
+EXPORT_SYMBOL_FOR_KVM(kvm_set_posted_intr_wakeup_handler);
 
 /*
  * Handler for POSTED_INTERRUPT_VECTOR.

arch/x86/kernel/kvm.c

···
 #include <linux/syscore_ops.h>
 #include <linux/cc_platform.h>
 #include <linux/efi.h>
+#include <linux/kvm_types.h>
 #include <asm/timer.h>
 #include <asm/cpu.h>
 #include <asm/traps.h>
···
 	}
 	finish_swait(&n.wq, &wait);
 }
-EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait_schedule);
+EXPORT_SYMBOL_FOR_KVM(kvm_async_pf_task_wait_schedule);
 
 static void apf_task_wake_one(struct kvm_task_sleep_node *n)
 {
···
 
 	return flags;
 }
-EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
+EXPORT_SYMBOL_FOR_KVM(kvm_read_and_reset_apf_flags);
 
 noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
 {

arch/x86/kernel/nmi.c

···
 #include <linux/export.h>
 #include <linux/atomic.h>
 #include <linux/sched/clock.h>
+#include <linux/kvm_types.h>
 
 #include <asm/cpu_entry_area.h>
 #include <asm/traps.h>
···
 {
 	exc_nmi(regs);
 }
-#if IS_MODULE(CONFIG_KVM_INTEL)
-EXPORT_SYMBOL_GPL(asm_exc_nmi_kvm_vmx);
-#endif
+EXPORT_SYMBOL_FOR_KVM(asm_exc_nmi_kvm_vmx);
 #endif
 
 #ifdef CONFIG_NMI_CHECK_CPU

arch/x86/kernel/process_64.c

···
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 #include <linux/ptrace.h>
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
···
 	save_fsgs(current);
 	local_irq_restore(flags);
 }
-#if IS_ENABLED(CONFIG_KVM)
-EXPORT_SYMBOL_GPL(current_save_fsgs);
-#endif
+EXPORT_SYMBOL_FOR_KVM(current_save_fsgs);
 
 static __always_inline void loadseg(enum which_selector which,
 				    unsigned short sel)

arch/x86/kernel/reboot.c

···
 #include <linux/objtool.h>
 #include <linux/pgtable.h>
 #include <linux/kexec.h>
+#include <linux/kvm_types.h>
 #include <acpi/reboot.h>
 #include <asm/io.h>
 #include <asm/apic.h>
···
 
 	rcu_assign_pointer(cpu_emergency_virt_callback, callback);
 }
-EXPORT_SYMBOL_GPL(cpu_emergency_register_virt_callback);
+EXPORT_SYMBOL_FOR_KVM(cpu_emergency_register_virt_callback);
 
 void cpu_emergency_unregister_virt_callback(cpu_emergency_virt_cb *callback)
 {
···
 	rcu_assign_pointer(cpu_emergency_virt_callback, NULL);
 	synchronize_rcu();
 }
-EXPORT_SYMBOL_GPL(cpu_emergency_unregister_virt_callback);
+EXPORT_SYMBOL_FOR_KVM(cpu_emergency_unregister_virt_callback);
 
 /*
  * Disable virtualization, i.e. VMX or SVM, to ensure INIT is recognized during

arch/x86/kernel/tsc.c

···
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/clocksource.h>
+#include <linux/kvm_types.h>
 #include <linux/percpu.h>
 #include <linux/timex.h>
 #include <linux/static_key.h>

arch/x86/lib/cache-smp.c

···
 #include <asm/paravirt.h>
 #include <linux/smp.h>
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 
 static void __wbinvd(void *dummy)
 {
···
 {
 	smp_call_function_single(cpu, __wbinvd, NULL, 1);
 }
-EXPORT_SYMBOL(wbinvd_on_cpu);
+EXPORT_SYMBOL_FOR_KVM(wbinvd_on_cpu);
 
 void wbinvd_on_all_cpus(void)
 {
···
 {
 	on_each_cpu_mask(cpus, __wbinvd, NULL, 1);
 }
-EXPORT_SYMBOL_GPL(wbinvd_on_cpus_mask);
+EXPORT_SYMBOL_FOR_KVM(wbinvd_on_cpus_mask);
 
 static void __wbnoinvd(void *dummy)
 {
···
 {
 	on_each_cpu(__wbnoinvd, NULL, 1);
 }
-EXPORT_SYMBOL_GPL(wbnoinvd_on_all_cpus);
+EXPORT_SYMBOL_FOR_KVM(wbnoinvd_on_all_cpus);
 
 void wbnoinvd_on_cpus_mask(struct cpumask *cpus)
 {
 	on_each_cpu_mask(cpus, __wbnoinvd, NULL, 1);
 }
-EXPORT_SYMBOL_GPL(wbnoinvd_on_cpus_mask);
+EXPORT_SYMBOL_FOR_KVM(wbnoinvd_on_cpus_mask);

arch/x86/lib/msr.c

···
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/export.h>
+#include <linux/kvm_types.h>
 #include <linux/percpu.h>
 #include <linux/preempt.h>
 #include <asm/msr.h>
···
 {
 	return __flip_bit(msr, bit, true);
 }
-EXPORT_SYMBOL_GPL(msr_set_bit);
+EXPORT_SYMBOL_FOR_KVM(msr_set_bit);
 
 /**
  * msr_clear_bit - Clear @bit in a MSR @msr.
···
 {
 	return __flip_bit(msr, bit, false);
 }
-EXPORT_SYMBOL_GPL(msr_clear_bit);
+EXPORT_SYMBOL_FOR_KVM(msr_clear_bit);
 
 #ifdef CONFIG_TRACEPOINTS
 void do_trace_write_msr(u32 msr, u64 val, int failed)

arch/x86/mm/pat/memtype.c

···
 #include <linux/highmem.h>
 #include <linux/fs.h>
 #include <linux/rbtree.h>
+#include <linux/kvm_types.h>
 
 #include <asm/cpu_device_id.h>
 #include <asm/cacheflush.h>
···
 	       cm == _PAGE_CACHE_MODE_UC_MINUS ||
 	       cm == _PAGE_CACHE_MODE_WC;
 }
-EXPORT_SYMBOL_GPL(pat_pfn_immune_to_uc_mtrr);
+EXPORT_SYMBOL_FOR_KVM(pat_pfn_immune_to_uc_mtrr);
 
 /**
  * memtype_reserve_io - Request a memory type mapping for a region of memory

arch/x86/mm/tlb.c

···
 #include <linux/task_work.h>
 #include <linux/mmu_notifier.h>
 #include <linux/mmu_context.h>
+#include <linux/kvm_types.h>
 
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
···
 	VM_BUG_ON(cr3 != __read_cr3());
 	return cr3;
 }
-EXPORT_SYMBOL_GPL(__get_current_cr3_fast);
+EXPORT_SYMBOL_FOR_KVM(__get_current_cr3_fast);
 
 /*
  * Flush one page in the kernel mapping
···
 		flush_tlb_local();
 	}
 }
-EXPORT_SYMBOL_GPL(__flush_tlb_all);
+EXPORT_SYMBOL_FOR_KVM(__flush_tlb_all);
 
 void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
 {

arch/x86/virt/vmx/tdx/tdx.c

···
 #include <linux/acpi.h>
 #include <linux/suspend.h>
 #include <linux/idr.h>
+#include <linux/kvm_types.h>
 #include <asm/page.h>
 #include <asm/special_insns.h>
 #include <asm/msr-index.h>
···
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(tdx_cpu_enable);
+EXPORT_SYMBOL_FOR_KVM(tdx_cpu_enable);
 
 /*
  * Add a memory region as a TDX memory block.  The caller must make sure
···
 {
 	tdx_quirk_reset_paddr(page_to_phys(page), PAGE_SIZE);
 }
-EXPORT_SYMBOL_GPL(tdx_quirk_reset_page);
+EXPORT_SYMBOL_FOR_KVM(tdx_quirk_reset_page);
 
 static void tdmr_quirk_reset_pamt(struct tdmr_info *tdmr)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdx_enable);
+EXPORT_SYMBOL_FOR_KVM(tdx_enable);
 
 static bool is_pamt_page(unsigned long phys)
 {
···
 
 	return p;
 }
-EXPORT_SYMBOL_GPL(tdx_get_sysinfo);
+EXPORT_SYMBOL_FOR_KVM(tdx_get_sysinfo);
 
 u32 tdx_get_nr_guest_keyids(void)
 {
 	return tdx_nr_guest_keyids;
 }
-EXPORT_SYMBOL_GPL(tdx_get_nr_guest_keyids);
+EXPORT_SYMBOL_FOR_KVM(tdx_get_nr_guest_keyids);
 
 int tdx_guest_keyid_alloc(void)
 {
···
 			       tdx_guest_keyid_start + tdx_nr_guest_keyids - 1,
 			       GFP_KERNEL);
 }
-EXPORT_SYMBOL_GPL(tdx_guest_keyid_alloc);
+EXPORT_SYMBOL_FOR_KVM(tdx_guest_keyid_alloc);
 
 void tdx_guest_keyid_free(unsigned int keyid)
 {
 	ida_free(&tdx_guest_keyid_pool, keyid);
 }
-EXPORT_SYMBOL_GPL(tdx_guest_keyid_free);
+EXPORT_SYMBOL_FOR_KVM(tdx_guest_keyid_free);
 
 static inline u64 tdx_tdr_pa(struct tdx_td *td)
 {
···
 
 	return __seamcall_dirty_cache(__seamcall_saved_ret, TDH_VP_ENTER, args);
 }
-EXPORT_SYMBOL_GPL(tdh_vp_enter);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_enter);
 
 u64 tdh_mng_addcx(struct tdx_td *td, struct page *tdcs_page)
 {
···
 	tdx_clflush_page(tdcs_page);
 	return seamcall(TDH_MNG_ADDCX, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mng_addcx);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_addcx);
 
 u64 tdh_mem_page_add(struct tdx_td *td, u64 gpa, struct page *page, struct page *source, u64 *ext_err1, u64 *ext_err2)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mem_page_add);
+EXPORT_SYMBOL_FOR_KVM(tdh_mem_page_add);
 
 u64 tdh_mem_sept_add(struct tdx_td *td, u64 gpa, int level, struct page *page, u64 *ext_err1, u64 *ext_err2)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mem_sept_add);
+EXPORT_SYMBOL_FOR_KVM(tdh_mem_sept_add);
 
 u64 tdh_vp_addcx(struct tdx_vp *vp, struct page *tdcx_page)
 {
···
 	tdx_clflush_page(tdcx_page);
 	return seamcall(TDH_VP_ADDCX, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_vp_addcx);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_addcx);
 
 u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, int level, struct page *page, u64 *ext_err1, u64 *ext_err2)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mem_page_aug);
+EXPORT_SYMBOL_FOR_KVM(tdh_mem_page_aug);
 
 u64 tdh_mem_range_block(struct tdx_td *td, u64 gpa, int level, u64 *ext_err1, u64 *ext_err2)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mem_range_block);
+EXPORT_SYMBOL_FOR_KVM(tdh_mem_range_block);
 
 u64 tdh_mng_key_config(struct tdx_td *td)
 {
···
 
 	return seamcall(TDH_MNG_KEY_CONFIG, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mng_key_config);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_key_config);
 
 u64 tdh_mng_create(struct tdx_td *td, u16 hkid)
 {
···
 	tdx_clflush_page(td->tdr_page);
 	return seamcall(TDH_MNG_CREATE, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mng_create);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_create);
 
 u64 tdh_vp_create(struct tdx_td *td, struct tdx_vp *vp)
 {
···
 	tdx_clflush_page(vp->tdvpr_page);
 	return seamcall(TDH_VP_CREATE, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_vp_create);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_create);
 
 u64 tdh_mng_rd(struct tdx_td *td, u64 field, u64 *data)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mng_rd);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_rd);
 
 u64 tdh_mr_extend(struct tdx_td *td, u64 gpa, u64 *ext_err1, u64 *ext_err2)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mr_extend);
+EXPORT_SYMBOL_FOR_KVM(tdh_mr_extend);
 
 u64 tdh_mr_finalize(struct tdx_td *td)
 {
···
 
 	return seamcall(TDH_MR_FINALIZE, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mr_finalize);
+EXPORT_SYMBOL_FOR_KVM(tdh_mr_finalize);
 
 u64 tdh_vp_flush(struct tdx_vp *vp)
 {
···
 
 	return seamcall(TDH_VP_FLUSH, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_vp_flush);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_flush);
 
 u64 tdh_mng_vpflushdone(struct tdx_td *td)
 {
···
 
 	return seamcall(TDH_MNG_VPFLUSHDONE, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mng_vpflushdone);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_vpflushdone);
 
 u64 tdh_mng_key_freeid(struct tdx_td *td)
 {
···
 
 	return seamcall(TDH_MNG_KEY_FREEID, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mng_key_freeid);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_key_freeid);
 
 u64 tdh_mng_init(struct tdx_td *td, u64 td_params, u64 *extended_err)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mng_init);
+EXPORT_SYMBOL_FOR_KVM(tdh_mng_init);
 
 u64 tdh_vp_rd(struct tdx_vp *vp, u64 field, u64 *data)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_vp_rd);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_rd);
 
 u64 tdh_vp_wr(struct tdx_vp *vp, u64 field, u64 data, u64 mask)
 {
···
 
 	return seamcall(TDH_VP_WR, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_vp_wr);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_wr);
 
 u64 tdh_vp_init(struct tdx_vp *vp, u64 initial_rcx, u32 x2apicid)
 {
···
 	/* apicid requires version == 1. */
 	return seamcall(TDH_VP_INIT | (1ULL << TDX_VERSION_SHIFT), &args);
 }
-EXPORT_SYMBOL_GPL(tdh_vp_init);
+EXPORT_SYMBOL_FOR_KVM(tdh_vp_init);
 
 /*
  * TDX ABI defines output operands as PT, OWNER and SIZE. These are TDX defined fomats.
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_phymem_page_reclaim);
+EXPORT_SYMBOL_FOR_KVM(tdh_phymem_page_reclaim);
 
 u64 tdh_mem_track(struct tdx_td *td)
 {
···
 
 	return seamcall(TDH_MEM_TRACK, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_mem_track);
+EXPORT_SYMBOL_FOR_KVM(tdh_mem_track);
 
 u64 tdh_mem_page_remove(struct tdx_td *td, u64 gpa, u64 level, u64 *ext_err1, u64 *ext_err2)
 {
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(tdh_mem_page_remove);
+EXPORT_SYMBOL_FOR_KVM(tdh_mem_page_remove);
 
 u64 tdh_phymem_cache_wb(bool resume)
 {
···
 
 	return seamcall(TDH_PHYMEM_CACHE_WB, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_phymem_cache_wb);
+EXPORT_SYMBOL_FOR_KVM(tdh_phymem_cache_wb);
 
 u64 tdh_phymem_page_wbinvd_tdr(struct tdx_td *td)
 {
···
 
 	return seamcall(TDH_PHYMEM_PAGE_WBINVD, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_phymem_page_wbinvd_tdr);
+EXPORT_SYMBOL_FOR_KVM(tdh_phymem_page_wbinvd_tdr);
 
 u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct page *page)
 {
···
 
 	return seamcall(TDH_PHYMEM_PAGE_WBINVD, &args);
 }
-EXPORT_SYMBOL_GPL(tdh_phymem_page_wbinvd_hkid);
+EXPORT_SYMBOL_FOR_KVM(tdh_phymem_page_wbinvd_hkid);
 
 #ifdef CONFIG_KEXEC_CORE
 void tdx_cpu_flush_cache_for_kexec(void)
···
 	wbinvd();
 	this_cpu_write(cache_state_incoherent, false);
 }
-EXPORT_SYMBOL_GPL(tdx_cpu_flush_cache_for_kexec);
+EXPORT_SYMBOL_FOR_KVM(tdx_cpu_flush_cache_for_kexec);
 #endif

include/linux/kvm_types.h

···
 #ifdef KVM_SUB_MODULES
 #define EXPORT_SYMBOL_FOR_KVM_INTERNAL(symbol) \
 	EXPORT_SYMBOL_FOR_MODULES(symbol, __stringify(KVM_SUB_MODULES))
+#define EXPORT_SYMBOL_FOR_KVM(symbol) \
+	EXPORT_SYMBOL_FOR_MODULES(symbol, "kvm," __stringify(KVM_SUB_MODULES))
 #else
 #define EXPORT_SYMBOL_FOR_KVM_INTERNAL(symbol)
+/*
+ * Allow architectures to provide a custom EXPORT_SYMBOL_FOR_KVM, but only
+ * if there are no submodules, e.g. to allow suppressing exports if KVM=m, but
+ * kvm.ko won't actually be built (due to lack of at least one submodule).
+ */
+#ifndef EXPORT_SYMBOL_FOR_KVM
+#if IS_MODULE(CONFIG_KVM)
+#define EXPORT_SYMBOL_FOR_KVM(symbol) EXPORT_SYMBOL_FOR_MODULES(symbol, "kvm")
+#else
+#define EXPORT_SYMBOL_FOR_KVM(symbol)
+#endif /* IS_MODULE(CONFIG_KVM) */
+#endif /* EXPORT_SYMBOL_FOR_KVM */
 #endif
 
 #ifndef __ASSEMBLER__