[patch V3 44/44] x86/idt: Hide set_intr_gate()

Thomas Gleixner
2017-08-28T06:53:56Z

[-- Attachment #1: x86-idt--Hide-set_intr_gate.patch --]
[-- Type: text/plain, Size: 2426 bytes --]

set_intr_gate() is an internal function of the IDT code. The only user left
is the KVM code which replaces the pagefault handler eventually.

Provide an explicit update_intr_gate() function and make set_intr_gate()
static. While at it replace the magic number 14 in the KVM code with the
proper trap define.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/desc.h | 2 +-
arch/x86/kernel/idt.c | 33 ++++++++++++++++++++-------------
arch/x86/kernel/kvm.c | 2 +-
3 files changed, 22 insertions(+), 15 deletions(-)

--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -390,7 +390,7 @@ static inline void set_desc_limit(struct
desc->limit1 = (limit >> 16) & 0xf;
}

-void set_intr_gate(unsigned int n, const void *addr);
+void update_intr_gate(unsigned int n, const void *addr);
void alloc_intr_gate(unsigned int n, const void *addr);

extern unsigned long used_vectors[];
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -225,6 +225,22 @@ idt_setup_from_table(gate_desc *idt, con
}
}

+static void set_intr_gate(unsigned int n, const void *addr)
+{
+ struct idt_data data;
+
+ BUG_ON(n > 0xFF);
+
+ memset(&data, 0, sizeof(data));
+ data.vector = n;
+ data.addr = addr;
+ data.segment = __KERNEL_CS;
+ data.bits.type = GATE_INTERRUPT;
+ data.bits.p = 1;
+
+ idt_setup_from_table(idt_table, &data, 1, false);
+}
+
/**
* idt_setup_early_traps - Initialize the idt table with early traps
*
@@ -336,20 +352,11 @@ void idt_invalidate(void *addr)
load_idt(&idt);
}

-void set_intr_gate(unsigned int n, const void *addr)
+void __init update_intr_gate(unsigned int n, const void *addr)
{
- struct idt_data data;
-
- BUG_ON(n > 0xFF);
-
- memset(&data, 0, sizeof(data));
- data.vector = n;
- data.addr = addr;
- data.segment = __KERNEL_CS;
- data.bits.type = GATE_INTERRUPT;
- data.bits.p = 1;
-
- idt_setup_from_table(idt_table, &data, 1, false);
+ if (WARN_ON_ONCE(!test_bit(n, used_vectors)))
+ return;
+ set_intr_gate(n, addr);
}

void alloc_intr_gate(unsigned int n, const void *addr)
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -455,7 +455,7 @@ static int kvm_cpu_down_prepare(unsigned

static void __init kvm_apf_trap_init(void)
{
- set_intr_gate(14, async_page_fault);
+ update_intr_gate(X86_TRAP_PF, async_page_fault);
}

void __init kvm_guest_init(void)