ple_window is updated on every vmentry, so there is no reason to have it
read-only anymore.
ple_window_* weren't writable to prevent runtime overflow races;
they are mitigated by clamping the value of ple_window.
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
If we decide to ignore insane overflows, last two hunks can be dropped.
arch/x86/kvm/vmx.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c6cfb71..d7f58e8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -134,19 +134,19 @@ static int ple_gap = KVM_VMX_DEFAULT_PLE_GAP;
module_param(ple_gap, int, S_IRUGO);
static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW;
-module_param(ple_window, int, S_IRUGO);
+module_param(ple_window, int, S_IRUGO | S_IWUSR);
/* Default doubles per-vcpu window every exit. */
static int ple_window_grow = KVM_VMX_DEFAULT_PLE_WINDOW_GROW;
-module_param(ple_window_grow, int, S_IRUGO);
+module_param(ple_window_grow, int, S_IRUGO | S_IWUSR);
/* Default resets per-vcpu window every exit to ple_window. */
static int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK;
-module_param(ple_window_shrink, int, S_IRUGO);
+module_param(ple_window_shrink, int, S_IRUGO | S_IWUSR);
/* 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);
+module_param(ple_window_max, int, S_IRUGO | S_IWUSR);
extern const ulong vmx_return;
@@ -5694,7 +5694,8 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
out:
return ret;
}
-#define make_ple_window_modifier(type, oplt, opge, cmp, bound) \
+
+#define make_ple_window_modifier(type, oplt, opge) \
static void type##_ple_window(struct kvm_vcpu *vcpu) \
{ \
struct vcpu_vmx *vmx = to_vmx(vcpu); \
@@ -5708,13 +5709,13 @@ static void type##_ple_window(struct kvm_vcpu *vcpu) \
else \
new = old opge ple_window_##type; \
\
- vmx->ple_window = cmp(new, bound); \
+ vmx->ple_window = clamp(new, ple_window, ple_window_max); \
\
trace_kvm_ple_window_##type(vcpu->vcpu_id, vmx->ple_window, old); \
}
-make_ple_window_modifier(grow, *, +, min, ple_window_max)
-make_ple_window_modifier(shrink, /, -, max, ple_window)
+make_ple_window_modifier(grow, *, +) /* grow_ple_window */
+make_ple_window_modifier(shrink, /, -) /* shrink_ple_window */
/*
* Indicate a busy-waiting vcpu in spinlock. We do not enable the PAUSE
--
2.0.4
--
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