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| author |   Babu Moger <babu.moger@amd.com> | 2018-03-16 16:37:23 -0400 |
|---|---|---|
| committer |   Radim Krčmář <rkrcmar@redhat.com> | 2018-03-28 22:47:06 +0200 |
| commit | 18abdc3425aa546424672d3b1f932ecc55132368 (patch) | |
| tree | 320e6c3f4fe3f0dbe2509cc81038d5aec3b9c825 /arch | |
| parent | KVM: VMX: Fix the module parameters for vmx (diff) | |
| download | wireguard-linux-18abdc3425aa546424672d3b1f932ecc55132368.tar.xz wireguard-linux-18abdc3425aa546424672d3b1f932ecc55132368.zip | |
KVM: VMX: Remove ple_window_actual_max
Get rid of ple_window_actual_max, because its benefits are really
minuscule and the logic is complicated.
The overflows(and underflow) are controlled in __ple_window_grow
and _ple_window_shrink respectively.
Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
[Fixed potential wraparound and change the max to UINT_MAX. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 31 |
1 files changed, 6 insertions, 25 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 4eb252b13121..7a92e2e1ea2e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -172,8 +172,7 @@ module_param_named(preemption_timer, enable_preemption_timer, bool, S_IRUGO); #define KVM_VMX_DEFAULT_PLE_WINDOW 4096 #define KVM_VMX_DEFAULT_PLE_WINDOW_GROW 2 #define KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK 0 -#define KVM_VMX_DEFAULT_PLE_WINDOW_MAX \ - INT_MAX / KVM_VMX_DEFAULT_PLE_WINDOW_GROW +#define KVM_VMX_DEFAULT_PLE_WINDOW_MAX UINT_MAX static unsigned int ple_gap = KVM_VMX_DEFAULT_PLE_GAP; module_param(ple_gap, uint, 0444); @@ -190,7 +189,6 @@ static unsigned int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK; module_param(ple_window_shrink, uint, 0444); /* Default is to compute the maximum so we can never overflow. */ -static unsigned int ple_window_actual_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX; static unsigned int ple_window_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX; module_param(ple_window_max, uint, 0444); @@ -6986,17 +6984,17 @@ out: static unsigned int __grow_ple_window(unsigned int val) { + u64 ret = val; + if (ple_window_grow < 1) return ple_window; - val = min(val, ple_window_actual_max); - if (ple_window_grow < ple_window) - val *= ple_window_grow; + ret *= ple_window_grow; else - val += ple_window_grow; + ret += ple_window_grow; - return val; + return min(ret, (u64)ple_window_max); } static unsigned int __shrink_ple_window(unsigned int val, @@ -7041,21 +7039,6 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu) } /* - * ple_window_actual_max is computed to be one grow_ple_window() below - * ple_window_max. (See __grow_ple_window for the reason.) - * This prevents overflows, because ple_window_max is int. - * ple_window_max effectively rounded down to a multiple of ple_window_grow in - * this process. - * ple_window_max is also prevented from setting vmx->ple_window < ple_window. - */ -static void update_ple_window_actual_max(void) -{ - ple_window_actual_max = - __shrink_ple_window(max(ple_window_max, ple_window), - ple_window_grow, INT_MIN); -} - -/* * Handler for POSTED_INTERRUPT_WAKEUP_VECTOR. */ static void wakeup_handler(void) @@ -7175,8 +7158,6 @@ static __init int hardware_setup(void) else kvm_disable_tdp(); - update_ple_window_actual_max(); - /* * Only enable PML when hardware supports PML feature, and both EPT * and EPT A/D bit features are enabled -- PML depends on them to work. |