[RFC PATCH 61/73] x86/pvm: Allow to install a system interrupt handler

[Lai Jiangshan <jiangshanlai@xxxxxxxxx>]

From: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx>

Add pvm_sysvec_install() to install a system interrupt handler into PVM
system interrupt handler table.

Signed-off-by: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx>
Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>
---
 arch/x86/include/asm/pvm_para.h |  6 ++++++
 arch/x86/kernel/kvm.c           |  2 ++
 arch/x86/kernel/pvm.c           | 11 +++++++++--
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pvm_para.h b/arch/x86/include/asm/pvm_para.h
index c344185a192c..9216e539fea8 100644
--- a/arch/x86/include/asm/pvm_para.h
+++ b/arch/x86/include/asm/pvm_para.h
@@ -6,12 +6,14 @@
 #include <uapi/asm/pvm_para.h>
 
 #ifndef __ASSEMBLY__
+typedef void (*idtentry_t)(struct pt_regs *regs);
 
 #ifdef CONFIG_PVM_GUEST
 #include <asm/irqflags.h>
 #include <uapi/asm/kvm_para.h>
 
 void __init pvm_early_setup(void);
+void __init pvm_install_sysvec(unsigned int sysvec, idtentry_t handler);
 bool __init pvm_kernel_layout_relocate(void);
 
 static inline void pvm_cpuid(unsigned int *eax, unsigned int *ebx,
@@ -68,6 +70,10 @@ static inline void pvm_early_setup(void)
 {
 }
 
+static inline void pvm_install_sysvec(unsigned int sysvec, idtentry_t handler)
+{
+}
+
 static inline bool pvm_kernel_layout_relocate(void)
 {
 	return false;
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index de72a5a1f7ad..87b00c279aaf 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -43,6 +43,7 @@
 #include <asm/reboot.h>
 #include <asm/svm.h>
 #include <asm/e820/api.h>
+#include <asm/pvm_para.h>
 
 DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
 
@@ -843,6 +844,7 @@ 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);
+		pvm_install_sysvec(HYPERVISOR_CALLBACK_VECTOR, sysvec_kvm_asyncpf_interrupt);
 	}
 
 #ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/pvm.c b/arch/x86/kernel/pvm.c
index 9399e45b3c13..88b013185ecd 100644
--- a/arch/x86/kernel/pvm.c
+++ b/arch/x86/kernel/pvm.c
@@ -128,8 +128,6 @@ static noinstr void pvm_handle_INT80_compat(struct pt_regs *regs)
 	exc_general_protection(regs, 0);
 }
 
-typedef void (*idtentry_t)(struct pt_regs *regs);
-
 #define SYSVEC(_vector, _function) [_vector - FIRST_SYSTEM_VECTOR] = sysvec_##_function
 
 #define pvm_handle_spurious_interrupt ((idtentry_t)(void *)spurious_interrupt)
@@ -167,6 +165,15 @@ static idtentry_t pvm_sysvec_table[NR_SYSTEM_VECTORS] __ro_after_init = {
 #endif
 };
 
+void __init pvm_install_sysvec(unsigned int sysvec, idtentry_t handler)
+{
+	if (WARN_ON_ONCE(sysvec < FIRST_SYSTEM_VECTOR))
+		return;
+	if (!WARN_ON_ONCE(pvm_sysvec_table[sysvec - FIRST_SYSTEM_VECTOR] !=
+			  pvm_handle_spurious_interrupt))
+		pvm_sysvec_table[sysvec - FIRST_SYSTEM_VECTOR] = handler;
+}
+
 /*
  * some pointers in pvm_sysvec_table are actual spurious_interrupt() who
  * expects the second argument to be the vector.
-- 
2.19.1.6.gb485710b