[PATCH RESEND v9 26/36] x86/traps: Add sysvec_install() to install a system interrupt handler

[Xin Li]

Add sysvec_install() to install a system interrupt handler into both
the IDT and system_interrupt_handlers. The latter is used to dispatch
system interrupts to their respective handlers when FRED is enabled.

Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
---

Changes since v8:
* Introduce a macro sysvec_install() to derive the asm handler name from
  a C handler, which simplifies the code and avoids an ugly typecast
  (Thomas Gleixner).
---
 arch/x86/include/asm/traps.h     | 19 +++++++++++++++++++
 arch/x86/kernel/cpu/acrn.c       |  5 +++--
 arch/x86/kernel/cpu/mshyperv.c   | 16 ++++++++--------
 arch/x86/kernel/kvm.c            |  2 +-
 arch/x86/kernel/traps.c          |  6 ++++++
 drivers/xen/events/events_base.c |  3 ++-
 6 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 47ecfff2c83d..cba3e4dfc329 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -47,4 +47,23 @@ void __noreturn handle_stack_overflow(struct pt_regs *regs,
 				      struct stack_info *info);
 #endif
 
+#ifdef CONFIG_X86_64
+inline void set_sysvec_handler(unsigned int i, system_interrupt_handler func);
+
+static inline void sysvec_setup_fred(unsigned int vector, system_interrupt_handler func)
+{
+	BUG_ON(vector < FIRST_SYSTEM_VECTOR);
+	set_sysvec_handler(vector - FIRST_SYSTEM_VECTOR, func);
+}
+#else
+static inline void sysvec_setup_fred(unsigned int vector, system_interrupt_handler func)
+{
+}
+#endif
+
+#define sysvec_install(vector, func) {					\
+	sysvec_setup_fred(vector, func);				\
+	alloc_intr_gate(vector, asm_##func);				\
+}
+
 #endif /* _ASM_X86_TRAPS_H */
diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c
index 485441b7f030..a879b4b87740 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 +27,8 @@ 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 */
+	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;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index c7969e806c64..134830a7f575 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -28,6 +28,7 @@
 #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>
@@ -480,19 +481,18 @@ 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,
-				asm_sysvec_hyperv_reenlightenment);
+		sysvec_install(HYPERV_REENLIGHTENMENT_VECTOR, 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);
+		sysvec_install(HYPERV_STIMER0_VECTOR, sysvec_hyperv_stimer0);
 	}
 
 # ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 1cceac5984da..12c799412c5d 100644
--- a/arch/x86/kernel/kvm.c
+++ b/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
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index e430a8c47931..9040c7f01c93 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -1536,6 +1536,12 @@ static system_interrupt_handler system_interrupt_handlers[NR_SYSTEM_VECTORS] = {
 
 #undef SYSV
 
+void set_sysvec_handler(unsigned int i, system_interrupt_handler func)
+{
+	BUG_ON(i >= NR_SYSTEM_VECTORS);
+	system_interrupt_handlers[i] = func;
+}
+
 #endif /* CONFIG_X86_64 */
 
 void __init trap_init(void)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index c7715f8bd452..16d51338e1f8 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
@@ -2249,7 +2250,7 @@ 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) {}
-- 
2.34.1