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From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Liran Alon" <liran.alon@oracle.com>
Subject: [PATCH v4 2/5] KVM: LAPIC: Fix lapic_timer_advance_ns parameter overflow
Date: Mon, 20 May 2019 16:18:06 +0800	[thread overview]
Message-ID: <1558340289-6857-3-git-send-email-wanpengli@tencent.com> (raw)
In-Reply-To: <1558340289-6857-1-git-send-email-wanpengli@tencent.com>

From: Wanpeng Li <wanpengli@tencent.com>

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@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
 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


  parent reply	other threads:[~2019-05-20  8:18 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-20  8:18 [PATCH v4 0/5] KVM: LAPIC: Optimize timer latency further Wanpeng Li
2019-05-20  8:18 ` [PATCH v4 1/5] KVM: LAPIC: Extract adaptive tune timer advancement logic Wanpeng Li
2019-05-20  8:18 ` Wanpeng Li [this message]
2019-05-20  8:18 ` [PATCH v4 3/5] KVM: LAPIC: Expose per-vCPU timer_advance_ns to userspace Wanpeng Li
2019-05-20  8:18 ` [PATCH v4 4/5] KVM: LAPIC: Delay trace advance expire delta Wanpeng Li
2019-05-20 11:14   ` Paolo Bonzini
2019-05-20 11:22     ` Wanpeng Li
2019-05-20 11:33       ` Paolo Bonzini
2019-05-20 11:36         ` Wanpeng Li
2019-05-20 11:41           ` Paolo Bonzini
2019-05-20 11:45             ` Wanpeng Li
2019-05-20  8:18 ` [PATCH v4 5/5] KVM: LAPIC: Optimize timer latency further Wanpeng Li
2019-05-20 11:16 ` [PATCH v4 0/5] " Paolo Bonzini
2019-05-22  8:51 ` Wanpeng Li

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