Modifications could get unwanted values of PLE window. (low or negative)
Use ple_window and the maximal value that cannot overflow as bounds.
ple_window_max defaults to a very high value, but it would make sense to
set it to some fraction of the scheduler tick.
Signed-off-by: Radim Krčmář <rkrc...@redhat.com>
---
arch/x86/kvm/vmx.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 66259fd..e1192fb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -144,6 +144,10 @@ module_param(ple_window_grow, int, S_IRUGO);
static int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK;
module_param(ple_window_shrink, int, S_IRUGO);
+/* Default is to compute the maximum so we can never overflow. */
+static int ple_window_max = INT_MAX / KVM_VMX_DEFAULT_PLE_WINDOW_GROW;
+module_param(ple_window_max, int, S_IRUGO);
+
extern const ulong vmx_return;
#define NR_AUTOLOAD_MSRS 8
@@ -5704,7 +5708,7 @@ static void grow_ple_window(struct kvm_vcpu *vcpu)
else
new = old + ple_window_grow;
- vmx->ple_window = new;
+ vmx->ple_window = min(new, ple_window_max);
}
static void shrink_ple_window(struct kvm_vcpu *vcpu)
@@ -5720,7 +5724,7 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu)
else
new = old - ple_window_shrink;
- vmx->ple_window = new;
+ vmx->ple_window = max(new, ple_window);
}
/*
--
2.0.4
--
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