linux-kernel - [PATCH v2 2/3] KVM: x86: introduce definitions to support static calls for kvm_x86

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Message-Id: <e5cc82ead7ab37b2dceb0837a514f3f8bea4f8d1.1610680941.git.jbaron@akamai.com>
Date:   Thu, 14 Jan 2021 22:27:55 -0500
From:   Jason Baron <jbaron@...mai.com>
To:     pbonzini@...hat.com, seanjc@...gle.com
Cc:     kvm@...r.kernel.org, x86@...nel.org, linux-kernel@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrea Arcangeli <aarcange@...hat.com>
Subject: [PATCH v2 2/3] KVM: x86: introduce definitions to support static calls for kvm_x86_ops

Use static calls to improve kvm_x86_ops performance. Introduce the
definitions that will be used by a subsequent patch to actualize the
savings. Add a new kvm-x86-ops.h header that can be used for the
definition of static calls. This header is also intended to be
used to simplify the defition of svm_kvm_ops and vmx_x86_ops.

Note that all functions in kvm_x86_ops are covered here except for
'pmu_ops' and 'nested ops'. I think they can be covered by static
calls in a simlilar manner, but were omitted from this series to
reduce scope and because I don't think they have as large of a
performance impact.

Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Signed-off-by: Jason Baron <jbaron@...mai.com>
---
 arch/x86/include/asm/kvm-x86-ops.h | 127 +++++++++++++++++++++++++++++++++++++
 arch/x86/include/asm/kvm_host.h    |  13 ++++
 arch/x86/kvm/x86.c                 |   9 +++
 3 files changed, 149 insertions(+)
 create mode 100644 arch/x86/include/asm/kvm-x86-ops.h

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
new file mode 100644
index 0000000..355a2ab
--- /dev/null
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#if !defined(KVM_X86_OP) || !defined(KVM_X86_OP_NULL)
+BUILD_BUG_ON(1)
+#endif
+
+/*
+ * KVM_X86_OP() and KVM_X86_OP_NULL() are used to help generate
+ * "static_call()"s. They are also intended for use when defining
+ * the vmx/svm kvm_x86_ops. KVM_X86_OP() can be used for those
+ * functions that follow the [svm|vmx]_func_name convention.
+ * KVM_X86_OP_NULL() can leave a NULL definition for the
+ * case where there is no definition or a function name that
+ * doesn't match the typical naming convention is supplied.
+ */
+KVM_X86_OP_NULL(hardware_enable)
+KVM_X86_OP_NULL(hardware_disable)
+KVM_X86_OP_NULL(hardware_unsetup)
+KVM_X86_OP_NULL(cpu_has_accelerated_tpr)
+KVM_X86_OP(has_emulated_msr)
+KVM_X86_OP(vcpu_after_set_cpuid)
+KVM_X86_OP(vm_init)
+KVM_X86_OP_NULL(vm_destroy)
+KVM_X86_OP(vcpu_create)
+KVM_X86_OP(vcpu_free)
+KVM_X86_OP(vcpu_reset)
+KVM_X86_OP(prepare_guest_switch)
+KVM_X86_OP(vcpu_load)
+KVM_X86_OP(vcpu_put)
+KVM_X86_OP(update_exception_bitmap)
+KVM_X86_OP(get_msr)
+KVM_X86_OP(set_msr)
+KVM_X86_OP(get_segment_base)
+KVM_X86_OP(get_segment)
+KVM_X86_OP(get_cpl)
+KVM_X86_OP(set_segment)
+KVM_X86_OP_NULL(get_cs_db_l_bits)
+KVM_X86_OP(set_cr0)
+KVM_X86_OP(is_valid_cr4)
+KVM_X86_OP(set_cr4)
+KVM_X86_OP(set_efer)
+KVM_X86_OP(get_idt)
+KVM_X86_OP(set_idt)
+KVM_X86_OP(get_gdt)
+KVM_X86_OP(set_gdt)
+KVM_X86_OP(sync_dirty_debug_regs)
+KVM_X86_OP(set_dr7)
+KVM_X86_OP(cache_reg)
+KVM_X86_OP(get_rflags)
+KVM_X86_OP(set_rflags)
+KVM_X86_OP(tlb_flush_all)
+KVM_X86_OP(tlb_flush_current)
+KVM_X86_OP_NULL(tlb_remote_flush)
+KVM_X86_OP_NULL(tlb_remote_flush_with_range)
+KVM_X86_OP(tlb_flush_gva)
+KVM_X86_OP(tlb_flush_guest)
+KVM_X86_OP(run)
+KVM_X86_OP_NULL(handle_exit)
+KVM_X86_OP_NULL(skip_emulated_instruction)
+KVM_X86_OP_NULL(update_emulated_instruction)
+KVM_X86_OP(set_interrupt_shadow)
+KVM_X86_OP(get_interrupt_shadow)
+KVM_X86_OP(patch_hypercall)
+KVM_X86_OP(set_irq)
+KVM_X86_OP(set_nmi)
+KVM_X86_OP(queue_exception)
+KVM_X86_OP(cancel_injection)
+KVM_X86_OP(interrupt_allowed)
+KVM_X86_OP(nmi_allowed)
+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(update_cr8_intercept)
+KVM_X86_OP(check_apicv_inhibit_reasons)
+KVM_X86_OP_NULL(pre_update_apicv_exec_ctrl)
+KVM_X86_OP(refresh_apicv_exec_ctrl)
+KVM_X86_OP(hwapic_irr_update)
+KVM_X86_OP(hwapic_isr_update)
+KVM_X86_OP_NULL(guest_apic_has_interrupt)
+KVM_X86_OP(load_eoi_exitmap)
+KVM_X86_OP(set_virtual_apic_mode)
+KVM_X86_OP_NULL(set_apic_access_page_addr)
+KVM_X86_OP(deliver_posted_interrupt)
+KVM_X86_OP_NULL(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_NULL(has_wbinvd_exit)
+KVM_X86_OP(write_l1_tsc_offset)
+KVM_X86_OP(get_exit_info)
+KVM_X86_OP(check_intercept)
+KVM_X86_OP(handle_exit_irqoff)
+KVM_X86_OP_NULL(request_immediate_exit)
+KVM_X86_OP(sched_in)
+KVM_X86_OP_NULL(slot_enable_log_dirty)
+KVM_X86_OP_NULL(slot_disable_log_dirty)
+KVM_X86_OP_NULL(flush_log_dirty)
+KVM_X86_OP_NULL(enable_log_dirty_pt_masked)
+KVM_X86_OP_NULL(cpu_dirty_log_size)
+KVM_X86_OP_NULL(pre_block)
+KVM_X86_OP_NULL(post_block)
+KVM_X86_OP_NULL(vcpu_blocking)
+KVM_X86_OP_NULL(vcpu_unblocking)
+KVM_X86_OP_NULL(update_pi_irte)
+KVM_X86_OP_NULL(apicv_post_state_restore)
+KVM_X86_OP_NULL(dy_apicv_has_pending_interrupt)
+KVM_X86_OP_NULL(set_hv_timer)
+KVM_X86_OP_NULL(cancel_hv_timer)
+KVM_X86_OP(setup_mce)
+KVM_X86_OP(smi_allowed)
+KVM_X86_OP(pre_enter_smm)
+KVM_X86_OP(pre_leave_smm)
+KVM_X86_OP(enable_smi_window)
+KVM_X86_OP_NULL(mem_enc_op)
+KVM_X86_OP_NULL(mem_enc_reg_region)
+KVM_X86_OP_NULL(mem_enc_unreg_region)
+KVM_X86_OP(get_msr_feature)
+KVM_X86_OP(can_emulate_instruction)
+KVM_X86_OP(apic_init_signal_blocked)
+KVM_X86_OP_NULL(enable_direct_tlbflush)
+KVM_X86_OP_NULL(migrate_timers)
+KVM_X86_OP(msr_filter_changed)
+KVM_X86_OP_NULL(complete_emulated_msr)
+
+#undef KVM_X86_OP
+#undef KVM_X86_OP_NULL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3ab7b46..5060922 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1326,6 +1326,19 @@ extern u64 __read_mostly host_efer;
 extern bool __read_mostly allow_smaller_maxphyaddr;
 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_NULL KVM_X86_OP
+#include <asm/kvm-x86-ops.h>
+
+static inline void kvm_ops_static_call_update(void)
+{
+#define KVM_X86_OP(func) \
+	static_call_update(kvm_x86_##func, kvm_x86_ops.func);
+#define KVM_X86_OP_NULL KVM_X86_OP
+#include <asm/kvm-x86-ops.h>
+}
+
 #define __KVM_HAVE_ARCH_VM_ALLOC
 static inline struct kvm *kvm_arch_alloc_vm(void)
 {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3f7c1fc..c21927f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -113,6 +113,15 @@ static int sync_regs(struct kvm_vcpu *vcpu);
 struct kvm_x86_ops kvm_x86_ops __read_mostly;
 EXPORT_SYMBOL_GPL(kvm_x86_ops);
 
+#define KVM_X86_OP(func)					     \
+	DEFINE_STATIC_CALL_NULL(kvm_x86_##func,			     \
+				*(((struct kvm_x86_ops *)0)->func));
+#define KVM_X86_OP_NULL 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);
+EXPORT_STATIC_CALL_GPL(kvm_x86_tlb_flush_current);
+
 static bool __read_mostly ignore_msrs = 0;
 module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
 
-- 
2.7.4