x86/idt/hyperv: Create a block interrupt gates for redirected interrupts

Create a block interrupt gates that start at FIRST_HV_VTL_REDIRECTED_
VECTOR. Service this interrupt with the function hv_vtl_redirected_
interrupt(). Only tell the APIC that the interrupt has been handled.
Subsequent changesets will use these interrupt vectors to deliver
their corresponding proxy interrupts to a VTL0 guest.

Signed-off-by: Ricardo Neri <[email protected]>
---
Changes since v1:
 * None

Author: ricardon

arch/x86/include/asm/hw_irq.h

@@ -121,6 +121,10 @@ extern char irq_entries_start[];
 
 extern char spurious_entries_start[];
 
+#ifdef CONFIG_HYPERV_VTL_MODE
+extern char hv_vtl_redirected_entries_start[];
+#endif
+
 #define VECTOR_UNUSED		NULL
 #define VECTOR_SHUTDOWN		((void *)-1L)
 #define VECTOR_RETRIGGERED	((void *)-2L)

arch/x86/include/asm/idtentry.h

@@ -586,6 +586,13 @@ DEFINE_IDTENTRY_STUBS(spurious_entries_start, FIRST_SYSTEM_VECTOR,
 		      NR_SYSTEM_VECTORS, spurious_interrupt)
 #endif
 
+#ifdef CONFIG_HYPERV_VTL_MODE
+DEFINE_IDTENTRY_STUBS(hv_vtl_redirected_entries_start,
+		      FIRST_HV_VTL_REDIRECTED_VECTOR,
+		      NR_HV_VTL_REDIRECTED_VECTORS,
+		      hv_vtl_redirected_interrupt)
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 /*
@@ -768,6 +775,9 @@ DECLARE_IDTENTRY_SYSVEC(POSTED_MSI_NOTIFICATION_VECTOR,	sysvec_posted_msi_notifi
 DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,	sysvec_hyperv_callback);
 DECLARE_IDTENTRY_SYSVEC(HYPERV_REENLIGHTENMENT_VECTOR,	sysvec_hyperv_reenlightenment);
 DECLARE_IDTENTRY_SYSVEC(HYPERV_STIMER0_VECTOR,		sysvec_hyperv_stimer0);
+#ifdef CONFIG_HYPERV_VTL_MODE
+DECLARE_IDTENTRY_IRQ(X86_TRAP_OTHER,			hv_vtl_redirected_interrupt);
+#endif
 #endif
 
 #if IS_ENABLED(CONFIG_ACRN_GUEST)

arch/x86/kernel/cpu/mshyperv.c

@@ -165,6 +165,13 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)
 	set_irq_regs(old_regs);
 }
 
+#ifdef CONFIG_HYPERV_VTL_MODE
+DEFINE_IDTENTRY_IRQ(hv_vtl_redirected_interrupt)
+{
+	apic_eoi();
+}
+#endif
+
 /* For x86/x64, override weak placeholders in hyperv_timer.c */
 void hv_setup_stimer0_handler(void (*handler)(void))
 {

arch/x86/kernel/idt.c

@@ -278,6 +278,20 @@ static void __init idt_map_in_cea(void)
 	idt_descr.address = CPU_ENTRY_AREA_RO_IDT;
 }
 
+static void __init idt_setup_hv_vtl_redirected_vectors(void)
+{
+#ifdef CONFIG_HYPERV_VTL_MODE
+	int i = FIRST_HV_VTL_REDIRECTED_VECTOR;
+
+	for (i = FIRST_HV_VTL_REDIRECTED_VECTOR; i < FIRST_SYSTEM_VECTOR; i++) {
+		void *entry = hv_vtl_redirected_entries_start +
+			      IDT_ALIGN * (i - FIRST_HV_VTL_REDIRECTED_VECTOR);
+		if (!WARN_ON(test_and_set_bit(i, system_vectors)))
+			set_intr_gate(i, entry);
+	}
+#endif
+}
+
 /**
  * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates
  */
@@ -288,6 +302,8 @@ void __init idt_setup_apic_and_irq_gates(void)
 
 	idt_setup_from_table(idt_table, apic_idts, ARRAY_SIZE(apic_idts), true);
 
+	idt_setup_hv_vtl_redirected_vectors();
+
 	for_each_clear_bit_from(i, system_vectors, FIRST_SYSTEM_VECTOR) {
 		entry = irq_entries_start + IDT_ALIGN * (i - FIRST_EXTERNAL_VECTOR);
 		set_intr_gate(i, entry);