4.9-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
commit 4c6523ec59fe895ea352a650218a6be0653910b1 upstream
Avoid the conditional in the L1D flush control path.
Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Jiri Kosina jkosina@suse.cz Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Josh Poimboeuf jpoimboe@redhat.com Link: https://lkml.kernel.org/r/20180713142322.790914912@linutronix.de Signed-off-by: David Woodhouse dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/vmx.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
--- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -193,6 +193,7 @@ module_param(ple_window_max, int, S_IRUG extern const ulong vmx_return;
static DEFINE_STATIC_KEY_FALSE(vmx_l1d_should_flush); +static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_always);
/* Storage for pre module init parameter parsing */ static enum vmx_l1d_flush_state __read_mostly vmentry_l1d_flush_param = VMENTER_L1D_FLUSH_AUTO; @@ -233,8 +234,12 @@ static int vmx_setup_l1d_flush(enum vmx_
l1tf_vmx_mitigation = l1tf;
- if (l1tf != VMENTER_L1D_FLUSH_NEVER) - static_branch_enable(&vmx_l1d_should_flush); + if (l1tf == VMENTER_L1D_FLUSH_NEVER) + return 0; + + static_branch_enable(&vmx_l1d_should_flush); + if (l1tf == VMENTER_L1D_FLUSH_ALWAYS) + static_branch_enable(&vmx_l1d_flush_always); return 0; }
@@ -8625,7 +8630,6 @@ static void *vmx_l1d_flush_pages; static void vmx_l1d_flush(struct kvm_vcpu *vcpu) { int size = PAGE_SIZE << L1D_CACHE_ORDER; - bool always;
/* * This code is only executed when the the flush mode is 'cond' or @@ -8635,8 +8639,10 @@ static void vmx_l1d_flush(struct kvm_vcp * it. The flush bit gets set again either from vcpu_run() or from * one of the unsafe VMEXIT handlers. */ - always = l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_ALWAYS; - vcpu->arch.l1tf_flush_l1d = always; + if (static_branch_unlikely(&vmx_l1d_flush_always)) + vcpu->arch.l1tf_flush_l1d = true; + else + vcpu->arch.l1tf_flush_l1d = false;
vcpu->stat.l1d_flush++;