[PATCH v4 2/5] KVM: LAPIC: Fix lapic_timer_advance_ns parameter overflow

[Wanpeng Li]

From: Wanpeng Li <wanpengli@xxxxxxxxxxx>

After commit c3941d9e0 (KVM: lapic: Allow user to disable adaptive tuning of
timer advancement), '-1' enables adaptive tuning starting from default
advancment of 1000ns. However, we should expose an int instead of an overflow
uint module parameter.

Before patch:

/sys/module/kvm/parameters/lapic_timer_advance_ns:4294967295

After patch:

/sys/module/kvm/parameters/lapic_timer_advance_ns:-1

Fixes: c3941d9e0 (KVM: lapic: Allow user to disable adaptive tuning of timer advancement)
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: Liran Alon <liran.alon@xxxxxxxxxx>
Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 784c953..3eb77e7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -143,7 +143,7 @@ module_param(tsc_tolerance_ppm, uint, S_IRUGO | S_IWUSR);
  * tuning, i.e. allows priveleged userspace to set an exact advancement time.
  */
 static int __read_mostly lapic_timer_advance_ns = -1;
-module_param(lapic_timer_advance_ns, uint, S_IRUGO | S_IWUSR);
+module_param(lapic_timer_advance_ns, int, S_IRUGO | S_IWUSR);
 
 static bool __read_mostly vector_hashing = true;
 module_param(vector_hashing, bool, S_IRUGO);
-- 
2.7.4