lkml.org 
[lkml]   [2019]   [Nov]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 2/4] KVM: ensure grow start value is nonzero
Date
vcpu->halt_poll_ns could be zeroed in certain cases (e.g. by
halt_poll_ns = 0). If halt_poll_grow_start is zero,
vcpu->halt_poll_ns will never be bigger than zero.

Use param callback to avoid writing zero to halt_poll_grow_start.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
---
virt/kvm/kvm_main.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d6f0696..359516b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -69,6 +69,26 @@
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");

+static int grow_start_set(const char *val, const struct kernel_param *kp)
+{
+ int ret;
+ unsigned int n;
+
+ if (!val)
+ return -EINVAL;
+
+ ret = kstrtouint(val, 0, &n);
+ if (ret || !n)
+ return -EINVAL;
+
+ return param_set_uint(val, kp);
+}
+
+static const struct kernel_param_ops grow_start_ops = {
+ .set = grow_start_set,
+ .get = param_get_uint,
+};
+
/* Architectures should define their poll value according to the halt latency */
unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, 0644);
@@ -81,7 +101,7 @@

/* The start value to grow halt_poll_ns from */
unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
-module_param(halt_poll_ns_grow_start, uint, 0644);
+module_param_cb(halt_poll_ns_grow_start, &grow_start_ops, &halt_poll_ns_grow_start, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);

/* Default resets per-vcpu halt_poll_ns . */
--
1.8.3.1
\
 
 \ /
  Last update: 2019-11-06 10:10    [W:0.106 / U:0.708 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site