x86/traps: Add sysvec_install() to install a system interrupt handler

Add sysvec_install() to install a system interrupt handler into the IDT
or the FRED system interrupt handler table.

Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Shan Kang <shan.kang@intel.com>
Link: https://lore.kernel.org/r/20231205105030.8698-28-xin3.li@intel.com

arch/x86/entry/entry_fred.c

@@ -119,6 +119,20 @@ static idtentry_t sysvec_table[NR_SYSTEM_VECTORS] __ro_after_init = {
 	SYSVEC(POSTED_INTR_NESTED_VECTOR,	kvm_posted_intr_nested_ipi),
 };
 
+static bool fred_setup_done __initdata;
+
+void __init fred_install_sysvec(unsigned int sysvec, idtentry_t handler)
+{
+	if (WARN_ON_ONCE(sysvec < FIRST_SYSTEM_VECTOR))
+		return;
+
+	if (WARN_ON_ONCE(fred_setup_done))
+		return;
+
+	if (!WARN_ON_ONCE(sysvec_table[sysvec - FIRST_SYSTEM_VECTOR]))
+		 sysvec_table[sysvec - FIRST_SYSTEM_VECTOR] = handler;
+}
+
 static noinstr void fred_extint(struct pt_regs *regs)
 {
 	unsigned int vector = regs->fred_ss.vector;

arch/x86/include/asm/desc.h

@@ -402,8 +402,6 @@ static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
 	desc->limit1 = (limit >> 16) & 0xf;
 }
 
-void alloc_intr_gate(unsigned int n, const void *addr);
-
 static inline void init_idt_data(struct idt_data *data, unsigned int n,
 				 const void *addr)
 {

arch/x86/include/asm/idtentry.h

@@ -459,6 +459,21 @@ __visible noinstr void func(struct pt_regs *regs,			\
 #define DEFINE_FREDENTRY_DEBUG		DEFINE_FREDENTRY_RAW
 #endif
 
+void idt_install_sysvec(unsigned int n, const void *function);
+
+#ifdef CONFIG_X86_FRED
+void fred_install_sysvec(unsigned int vector, const idtentry_t function);
+#else
+static inline void fred_install_sysvec(unsigned int vector, const idtentry_t function) { }
+#endif
+
+#define sysvec_install(vector, function) {				\
+	if (cpu_feature_enabled(X86_FEATURE_FRED))			\
+		fred_install_sysvec(vector, function);			\
+	else								\
+		idt_install_sysvec(vector, asm_##function);		\
+}
+
 #else /* !__ASSEMBLY__ */
 
 /*

arch/x86/kernel/cpu/acrn.c

@@ -26,8 +26,8 @@ static u32 __init acrn_detect(void)
 
 static void __init acrn_init_platform(void)
 {
-	/* Setup the IDT for ACRN hypervisor callback */
+	/* Install system interrupt handler for ACRN hypervisor callback */
-	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_acrn_hv_callback);
+	sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_acrn_hv_callback);
 
 	x86_platform.calibrate_tsc = acrn_get_tsc_khz;
 	x86_platform.calibrate_cpu = acrn_get_tsc_khz;

arch/x86/kernel/cpu/mshyperv.c

@@ -539,19 +539,18 @@ static void __init ms_hyperv_init_platform(void)
 	 */
 	x86_platform.apic_post_init = hyperv_init;
 	hyperv_setup_mmu_ops();
-	/* Setup the IDT for hypervisor callback */
-	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback);
 
-	/* Setup the IDT for reenlightenment notifications */
+	/* Install system interrupt handler for hypervisor callback */
+	sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_hyperv_callback);
+
+	/* Install system interrupt handler for reenlightenment notifications */
 	if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
-		alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
+		sysvec_install(HYPERV_REENLIGHTENMENT_VECTOR, sysvec_hyperv_reenlightenment);
-				asm_sysvec_hyperv_reenlightenment);
 	}
 
-	/* Setup the IDT for stimer0 */
+	/* Install system interrupt handler for stimer0 */
 	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
-		alloc_intr_gate(HYPERV_STIMER0_VECTOR,
+		sysvec_install(HYPERV_STIMER0_VECTOR, sysvec_hyperv_stimer0);
-				asm_sysvec_hyperv_stimer0);
 	}
 
 # ifdef CONFIG_SMP

arch/x86/kernel/idt.c

@@ -337,7 +337,7 @@ void idt_invalidate(void)
 	load_idt(&idt);
 }
 
-void __init alloc_intr_gate(unsigned int n, const void *addr)
+void __init idt_install_sysvec(unsigned int n, const void *function)
 {
 	if (WARN_ON(n < FIRST_SYSTEM_VECTOR))
 		return;
@@ -346,5 +346,5 @@ void __init alloc_intr_gate(unsigned int n, const void *addr)
 		return;
 
 	if (!WARN_ON(test_and_set_bit(n, system_vectors)))
-		set_intr_gate(n, addr);
+		set_intr_gate(n, function);
 }

arch/x86/kernel/kvm.c

@@ -829,7 +829,7 @@ static void __init kvm_guest_init(void)
 
 	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
 		static_branch_enable(&kvm_async_pf_enabled);
-		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt);
+		sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_kvm_asyncpf_interrupt);
 	}
 
 #ifdef CONFIG_SMP

drivers/xen/events/events_base.c

@@ -2216,7 +2216,7 @@ static __init void xen_alloc_callback_vector(void)
 		return;
 
 	pr_info("Xen HVM callback vector for event delivery is enabled\n");
-	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_xen_hvm_callback);
+	sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_xen_hvm_callback);
 }
 #else
 void xen_setup_callback_vector(void) {}