From: Vitaly Kuznetsov vkuznets@redhat.com
[ Upstream commit 1f1fbc70c10e81f70e9fbe2102d439c883269811 ]
With commit dc20b2d52653 ("x86/idt: Move interrupt gate initialization to IDT code") non assigned system vectors are also marked as used in 'used_vectors' (now 'system_vectors') bitmap. This makes checks in arch_show_interrupts() whether a particular system vector is allocated to always pass and e.g. 'Hyper-V reenlightenment interrupts' entry always shows up in /proc/interrupts.
Another side effect of having all unassigned system vectors marked as used is that irq_matrix_debug_show() will wrongly count them among 'System' vectors.
As it is now ensured that alloc_intr_gate() is not called after init, it is possible to leave unused entries in 'system_vectors' unset to fix these issues.
Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lkml.kernel.org/r/20200428093824.1451532-4-vkuznets@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/idt.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 87ef69a72c52e..7bb4c3cbf4dcd 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -318,7 +318,11 @@ void __init idt_setup_apic_and_irq_gates(void)
#ifdef CONFIG_X86_LOCAL_APIC for_each_clear_bit_from(i, system_vectors, NR_VECTORS) { - set_bit(i, system_vectors); + /* + * Don't set the non assigned system vectors in the + * system_vectors bitmap. Otherwise they show up in + * /proc/interrupts. + */ entry = spurious_entries_start + 8 * (i - FIRST_SYSTEM_VECTOR); set_intr_gate(i, entry); }