[RFC][PATCH 5/5] x86/kvm: Simplify static call handling

From: Josh Poimboeuf
Date: Fri Mar 10 2023 - 15:34:12 EST

Next message: Josh Poimboeuf: "[RFC][PATCH 4/5] static_call: Remove DEFINE_STATIC_CALL_RET0() and its uses"
Previous message: Josh Poimboeuf: "[RFC][PATCH 1/5] static_call: Make NULL static calls consistent"
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Next in thread: Sean Christopherson: "Re: [RFC][PATCH 5/5] x86/kvm: Simplify static call handling"
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Static calls with a NULL function pointer are now "do nothing return 0"
functions by default. Simplify the KVM static call handling
accordingly.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/include/asm/kvm-x86-ops.h | 85 ++++++++++++--------------
arch/x86/include/asm/kvm-x86-pmu-ops.h | 16 ++---
arch/x86/include/asm/kvm_host.h | 2 -
arch/x86/kvm/pmu.c | 7 +--
arch/x86/kvm/x86.c | 12 +---
5 files changed, 48 insertions(+), 74 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 2f0bfd910637..ea18a8abf4a1 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -1,17 +1,12 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#if !defined(KVM_X86_OP) || !defined(KVM_X86_OP_OPTIONAL)
+#if !defined(KVM_X86_OP)
BUILD_BUG_ON(1)
#endif

/*
- * KVM_X86_OP() and KVM_X86_OP_OPTIONAL() are used to help generate
- * both DECLARE/DEFINE_STATIC_CALL() invocations and
- * "static_call_update()" calls.
- *
- * KVM_X86_OP_OPTIONAL() can be used for those functions that can have
- * a NULL definition. KVM_X86_OP_OPTIONAL_RET0() can be used likewise
- * to make a definition optional, but in this case the default will
- * be __static_call_return0.
+ * KVM_X86_OP() is used to help generate both DECLARE/DEFINE_STATIC_CALL()
+ * invocations and "static_call_update()" calls. Note that NULL static calls
+ * default to "do-nothing return 0" functions.
*/
KVM_X86_OP(check_processor_compatibility)
KVM_X86_OP(hardware_enable)
@@ -20,8 +15,8 @@ KVM_X86_OP(hardware_unsetup)
KVM_X86_OP(has_emulated_msr)
KVM_X86_OP(vcpu_after_set_cpuid)
KVM_X86_OP(vm_init)
-KVM_X86_OP_OPTIONAL(vm_destroy)
-KVM_X86_OP_OPTIONAL_RET0(vcpu_precreate)
+KVM_X86_OP(vm_destroy)
+KVM_X86_OP(vcpu_precreate)
KVM_X86_OP(vcpu_create)
KVM_X86_OP(vcpu_free)
KVM_X86_OP(vcpu_reset)
@@ -37,7 +32,7 @@ KVM_X86_OP(get_cpl)
KVM_X86_OP(set_segment)
KVM_X86_OP(get_cs_db_l_bits)
KVM_X86_OP(set_cr0)
-KVM_X86_OP_OPTIONAL(post_set_cr3)
+KVM_X86_OP(post_set_cr3)
KVM_X86_OP(is_valid_cr4)
KVM_X86_OP(set_cr4)
KVM_X86_OP(set_efer)
@@ -53,15 +48,15 @@ KVM_X86_OP(set_rflags)
KVM_X86_OP(get_if_flag)
KVM_X86_OP(flush_tlb_all)
KVM_X86_OP(flush_tlb_current)
-KVM_X86_OP_OPTIONAL(tlb_remote_flush)
-KVM_X86_OP_OPTIONAL(tlb_remote_flush_with_range)
+KVM_X86_OP(tlb_remote_flush)
+KVM_X86_OP(tlb_remote_flush_with_range)
KVM_X86_OP(flush_tlb_gva)
KVM_X86_OP(flush_tlb_guest)
KVM_X86_OP(vcpu_pre_run)
KVM_X86_OP(vcpu_run)
KVM_X86_OP(handle_exit)
KVM_X86_OP(skip_emulated_instruction)
-KVM_X86_OP_OPTIONAL(update_emulated_instruction)
+KVM_X86_OP(update_emulated_instruction)
KVM_X86_OP(set_interrupt_shadow)
KVM_X86_OP(get_interrupt_shadow)
KVM_X86_OP(patch_hypercall)
@@ -75,19 +70,19 @@ KVM_X86_OP(get_nmi_mask)
KVM_X86_OP(set_nmi_mask)
KVM_X86_OP(enable_nmi_window)
KVM_X86_OP(enable_irq_window)
-KVM_X86_OP_OPTIONAL(update_cr8_intercept)
+KVM_X86_OP(update_cr8_intercept)
KVM_X86_OP(refresh_apicv_exec_ctrl)
-KVM_X86_OP_OPTIONAL(hwapic_irr_update)
-KVM_X86_OP_OPTIONAL(hwapic_isr_update)
-KVM_X86_OP_OPTIONAL_RET0(guest_apic_has_interrupt)
-KVM_X86_OP_OPTIONAL(load_eoi_exitmap)
-KVM_X86_OP_OPTIONAL(set_virtual_apic_mode)
-KVM_X86_OP_OPTIONAL(set_apic_access_page_addr)
+KVM_X86_OP(hwapic_irr_update)
+KVM_X86_OP(hwapic_isr_update)
+KVM_X86_OP(guest_apic_has_interrupt)
+KVM_X86_OP(load_eoi_exitmap)
+KVM_X86_OP(set_virtual_apic_mode)
+KVM_X86_OP(set_apic_access_page_addr)
KVM_X86_OP(deliver_interrupt)
-KVM_X86_OP_OPTIONAL(sync_pir_to_irr)
-KVM_X86_OP_OPTIONAL_RET0(set_tss_addr)
-KVM_X86_OP_OPTIONAL_RET0(set_identity_map_addr)
-KVM_X86_OP_OPTIONAL_RET0(get_mt_mask)
+KVM_X86_OP(sync_pir_to_irr)
+KVM_X86_OP(set_tss_addr)
+KVM_X86_OP(set_identity_map_addr)
+KVM_X86_OP(get_mt_mask)
KVM_X86_OP(load_mmu_pgd)
KVM_X86_OP(has_wbinvd_exit)
KVM_X86_OP(get_l2_tsc_offset)
@@ -99,15 +94,15 @@ KVM_X86_OP(check_intercept)
KVM_X86_OP(handle_exit_irqoff)
KVM_X86_OP(request_immediate_exit)
KVM_X86_OP(sched_in)
-KVM_X86_OP_OPTIONAL(update_cpu_dirty_logging)
-KVM_X86_OP_OPTIONAL(vcpu_blocking)
-KVM_X86_OP_OPTIONAL(vcpu_unblocking)
-KVM_X86_OP_OPTIONAL(pi_update_irte)
-KVM_X86_OP_OPTIONAL(pi_start_assignment)
-KVM_X86_OP_OPTIONAL(apicv_post_state_restore)
-KVM_X86_OP_OPTIONAL_RET0(dy_apicv_has_pending_interrupt)
-KVM_X86_OP_OPTIONAL(set_hv_timer)
-KVM_X86_OP_OPTIONAL(cancel_hv_timer)
+KVM_X86_OP(update_cpu_dirty_logging)
+KVM_X86_OP(vcpu_blocking)
+KVM_X86_OP(vcpu_unblocking)
+KVM_X86_OP(pi_update_irte)
+KVM_X86_OP(pi_start_assignment)
+KVM_X86_OP(apicv_post_state_restore)
+KVM_X86_OP(dy_apicv_has_pending_interrupt)
+KVM_X86_OP(set_hv_timer)
+KVM_X86_OP(cancel_hv_timer)
KVM_X86_OP(setup_mce)
#ifdef CONFIG_KVM_SMM
KVM_X86_OP(smi_allowed)
@@ -115,22 +110,20 @@ KVM_X86_OP(enter_smm)
KVM_X86_OP(leave_smm)
KVM_X86_OP(enable_smi_window)
#endif
-KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
-KVM_X86_OP_OPTIONAL(mem_enc_register_region)
-KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
-KVM_X86_OP_OPTIONAL(vm_copy_enc_context_from)
-KVM_X86_OP_OPTIONAL(vm_move_enc_context_from)
-KVM_X86_OP_OPTIONAL(guest_memory_reclaimed)
+KVM_X86_OP(mem_enc_ioctl)
+KVM_X86_OP(mem_enc_register_region)
+KVM_X86_OP(mem_enc_unregister_region)
+KVM_X86_OP(vm_copy_enc_context_from)
+KVM_X86_OP(vm_move_enc_context_from)
+KVM_X86_OP(guest_memory_reclaimed)
KVM_X86_OP(get_msr_feature)
KVM_X86_OP(can_emulate_instruction)
KVM_X86_OP(apic_init_signal_blocked)
-KVM_X86_OP_OPTIONAL(enable_l2_tlb_flush)
-KVM_X86_OP_OPTIONAL(migrate_timers)
+KVM_X86_OP(enable_l2_tlb_flush)
+KVM_X86_OP(migrate_timers)
KVM_X86_OP(msr_filter_changed)
KVM_X86_OP(complete_emulated_msr)
KVM_X86_OP(vcpu_deliver_sipi_vector)
-KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
+KVM_X86_OP(vcpu_get_apicv_inhibit_reasons);

#undef KVM_X86_OP
-#undef KVM_X86_OP_OPTIONAL
-#undef KVM_X86_OP_OPTIONAL_RET0
diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
index 6815319c4ff3..b11885d1bcd4 100644
--- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
+++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
@@ -1,15 +1,12 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#if !defined(KVM_X86_PMU_OP) || !defined(KVM_X86_PMU_OP_OPTIONAL)
+#if !defined(KVM_X86_PMU_OP)
BUILD_BUG_ON(1)
#endif

/*
- * KVM_X86_PMU_OP() and KVM_X86_PMU_OP_OPTIONAL() are used to help generate
- * both DECLARE/DEFINE_STATIC_CALL() invocations and
- * "static_call_update()" calls.
- *
- * KVM_X86_PMU_OP_OPTIONAL() can be used for those functions that can have
- * a NULL definition.
+ * KVM_X86_PMU_OP() is used to help generate both DECLARE/DEFINE_STATIC_CALL()
+ * invocations and "static_call_update()" calls. Note that NULL static calls
+ * default to "do-nothing return 0" functions.
*/
KVM_X86_PMU_OP(hw_event_available)
KVM_X86_PMU_OP(pmc_is_enabled)
@@ -23,8 +20,7 @@ KVM_X86_PMU_OP(set_msr)
KVM_X86_PMU_OP(refresh)
KVM_X86_PMU_OP(init)
KVM_X86_PMU_OP(reset)
-KVM_X86_PMU_OP_OPTIONAL(deliver_pmi)
-KVM_X86_PMU_OP_OPTIONAL(cleanup)
+KVM_X86_PMU_OP(deliver_pmi)
+KVM_X86_PMU_OP(cleanup)

#undef KVM_X86_PMU_OP
-#undef KVM_X86_PMU_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1dfba499d3e5..612531e1c478 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1789,8 +1789,6 @@ extern struct kvm_x86_ops kvm_x86_ops;

#define KVM_X86_OP(func) \
DECLARE_STATIC_CALL(kvm_x86_##func, *(((struct kvm_x86_ops *)0)->func));
-#define KVM_X86_OP_OPTIONAL KVM_X86_OP
-#define KVM_X86_OP_OPTIONAL_RET0 KVM_X86_OP
#include <asm/kvm-x86-ops.h>

int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops);
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 6accb46295a3..5f7f860c5f17 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -77,20 +77,15 @@ static struct kvm_pmu_ops kvm_pmu_ops __read_mostly;
#define KVM_X86_PMU_OP(func) \
DEFINE_STATIC_CALL_NULL(kvm_x86_pmu_##func, \
*(((struct kvm_pmu_ops *)0)->func));
-#define KVM_X86_PMU_OP_OPTIONAL KVM_X86_PMU_OP
#include <asm/kvm-x86-pmu-ops.h>

void kvm_pmu_ops_update(const struct kvm_pmu_ops *pmu_ops)
{
memcpy(&kvm_pmu_ops, pmu_ops, sizeof(kvm_pmu_ops));

-#define __KVM_X86_PMU_OP(func) \
- static_call_update(kvm_x86_pmu_##func, kvm_pmu_ops.func);
#define KVM_X86_PMU_OP(func) \
- WARN_ON(!kvm_pmu_ops.func); __KVM_X86_PMU_OP(func)
-#define KVM_X86_PMU_OP_OPTIONAL __KVM_X86_PMU_OP
+ static_call_update(kvm_x86_pmu_##func, kvm_pmu_ops.func);
#include <asm/kvm-x86-pmu-ops.h>
-#undef __KVM_X86_PMU_OP
}

static inline bool pmc_is_enabled(struct kvm_pmc *pmc)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fcf845fc5770..a9521e5b2435 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -135,9 +135,8 @@ struct kvm_x86_ops kvm_x86_ops __read_mostly;
#define KVM_X86_OP(func) \
DEFINE_STATIC_CALL_NULL(kvm_x86_##func, \
*(((struct kvm_x86_ops *)0)->func));
-#define KVM_X86_OP_OPTIONAL KVM_X86_OP
-#define KVM_X86_OP_OPTIONAL_RET0 KVM_X86_OP
#include <asm/kvm-x86-ops.h>
+
EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);

@@ -9316,16 +9315,9 @@ static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)
{
memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));

-#define __KVM_X86_OP(func) \
- static_call_update(kvm_x86_##func, kvm_x86_ops.func);
#define KVM_X86_OP(func) \
- WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
-#define KVM_X86_OP_OPTIONAL __KVM_X86_OP
-#define KVM_X86_OP_OPTIONAL_RET0(func) \
- static_call_update(kvm_x86_##func, (void *)kvm_x86_ops.func ? : \
- (void *)__static_call_return0);
+ static_call_update(kvm_x86_##func, kvm_x86_ops.func);
#include <asm/kvm-x86-ops.h>
-#undef __KVM_X86_OP

kvm_pmu_ops_update(ops->pmu_ops);
}
--
2.39.2

Next message: Josh Poimboeuf: "[RFC][PATCH 4/5] static_call: Remove DEFINE_STATIC_CALL_RET0() and its uses"
Previous message: Josh Poimboeuf: "[RFC][PATCH 1/5] static_call: Make NULL static calls consistent"
In reply to: Peter Zijlstra: "Re: [RFC][PATCH 1/5] static_call: Make NULL static calls consistent"
Next in thread: Sean Christopherson: "Re: [RFC][PATCH 5/5] x86/kvm: Simplify static call handling"
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