[RFC PATCH 03/32] x86/traps: add install_system_interrupt_handler()

[Xin Li <xin3.li@intel.com>]

Some kernel components install system interrupt handlers into the IDT,
and we need to do the same for system_interrupt_handlers. A new function
install_system_interrupt_handler() is added to install a system interrupt
handler into both the IDT and system_interrupt_handlers.

Signed-off-by: Xin Li <xin3.li@intel.com>
---
 arch/x86/include/asm/traps.h     |  2 ++
 arch/x86/kernel/cpu/acrn.c       |  7 +++++--
 arch/x86/kernel/cpu/mshyperv.c   | 22 ++++++++++++++--------
 arch/x86/kernel/kvm.c            |  4 +++-
 arch/x86/kernel/traps.c          |  8 ++++++++
 drivers/xen/events/events_base.c |  5 ++++-
 6 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 28c8ba5fd81c..46f5e4e2a346 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -41,6 +41,8 @@ void math_emulate(struct math_emu_info *);
 
 bool fault_in_kernel_space(unsigned long address);
 
+void install_system_interrupt_handler(unsigned int n, const void *asm_addr, const void *addr);
+
 #ifdef CONFIG_VMAP_STACK
 void __noreturn handle_stack_overflow(struct pt_regs *regs,
 				      unsigned long fault_address,
diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c
index 485441b7f030..9351bf183a9e 100644
--- a/arch/x86/kernel/cpu/acrn.c
+++ b/arch/x86/kernel/cpu/acrn.c
@@ -18,6 +18,7 @@
 #include <asm/hypervisor.h>
 #include <asm/idtentry.h>
 #include <asm/irq_regs.h>
+#include <asm/traps.h>
 
 static u32 __init acrn_detect(void)
 {
@@ -26,8 +27,10 @@ static u32 __init acrn_detect(void)
 
 static void __init acrn_init_platform(void)
 {
-	/* Setup the IDT for ACRN hypervisor callback */
-	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_acrn_hv_callback);
+	/* Install system interrupt handler for ACRN hypervisor callback */
+	install_system_interrupt_handler(HYPERVISOR_CALLBACK_VECTOR,
+					 asm_sysvec_acrn_hv_callback,
+					 sysvec_acrn_hv_callback);
 
 	x86_platform.calibrate_tsc = acrn_get_tsc_khz;
 	x86_platform.calibrate_cpu = acrn_get_tsc_khz;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..144b4a622188 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -29,6 +29,7 @@
 #include <asm/i8259.h>
 #include <asm/apic.h>
 #include <asm/timer.h>
+#include <asm/traps.h>
 #include <asm/reboot.h>
 #include <asm/nmi.h>
 #include <clocksource/hyperv_timer.h>
@@ -415,19 +416,24 @@ 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 */
+	install_system_interrupt_handler(HYPERVISOR_CALLBACK_VECTOR,
+					 asm_sysvec_hyperv_callback,
+					 sysvec_hyperv_callback);
+
+	/* Install system interrupt handler for reenlightenment notifications */
 	if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
-		alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
-				asm_sysvec_hyperv_reenlightenment);
+		install_system_interrupt_handler(HYPERV_REENLIGHTENMENT_VECTOR,
+						 asm_sysvec_hyperv_reenlightenment,
+						 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,
-				asm_sysvec_hyperv_stimer0);
+		install_system_interrupt_handler(HYPERV_STIMER0_VECTOR,
+						 asm_sysvec_hyperv_stimer0,
+						 sysvec_hyperv_stimer0);
 	}
 
 # ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index d4e48b4a438b..b7388ed2a980 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -835,7 +835,9 @@ 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);
+		install_system_interrupt_handler(HYPERVISOR_CALLBACK_VECTOR,
+						 asm_sysvec_kvm_asyncpf_interrupt,
+						 sysvec_kvm_asyncpf_interrupt);
 	}
 
 #ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 8f751c06c052..2b8530235e47 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -1491,6 +1491,14 @@ static system_interrupt_handler system_interrupt_handlers[NR_SYSTEM_VECTORS] = {
 
 #undef SYSV
 
+void __init install_system_interrupt_handler(unsigned int n, const void *asm_addr, const void *addr)
+{
+	BUG_ON(n < FIRST_SYSTEM_VECTOR);
+
+	system_interrupt_handlers[n - FIRST_SYSTEM_VECTOR] = (system_interrupt_handler)addr;
+	alloc_intr_gate(n, asm_addr);
+}
+
 void __init trap_init(void)
 {
 	/* Init cpu_entry_area before IST entries are set up */
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index c443f04aaad7..1a9eaf417acc 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -45,6 +45,7 @@
 #include <asm/irq.h>
 #include <asm/io_apic.h>
 #include <asm/i8259.h>
+#include <asm/traps.h>
 #include <asm/xen/cpuid.h>
 #include <asm/xen/pci.h>
 #endif
@@ -2246,7 +2247,9 @@ 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);
+	install_system_interrupt_handler(HYPERVISOR_CALLBACK_VECTOR,
+					 asm_sysvec_xen_hvm_callback,
+					 sysvec_xen_hvm_callback);
 }
 #else
 void xen_setup_callback_vector(void) {}
-- 
2.34.1