[PATCH 4.14 081/104] x86/KVM/VMX: Dont set l1tf_flush_l1d to true from vmx_l1d_flush()

From: Greg Kroah-Hartman
Date: Tue Aug 14 2018 - 13:38:56 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Nicolai Stange <nstange@xxxxxxx>

commit 379fd0c7e6a391e5565336a646f19f218fb98c6c upstream

vmx_l1d_flush() gets invoked only if l1tf_flush_l1d is true. There's no
point in setting l1tf_flush_l1d to true from there again.

Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9166,15 +9166,15 @@ static void vmx_l1d_flush(struct kvm_vcp
/*
* This code is only executed when the the flush mode is 'cond' or
* 'always'
- *
- * If 'flush always', keep the flush bit set, otherwise clear
- * it. The flush bit gets set again either from vcpu_run() or from
- * one of the unsafe VMEXIT handlers.
*/
- if (static_branch_unlikely(&vmx_l1d_flush_always))
- vcpu->arch.l1tf_flush_l1d = true;
- else
+ if (!static_branch_unlikely(&vmx_l1d_flush_always)) {
+ /*
+ * Clear the flush bit, it gets set again either from
+ * vcpu_run() or from one of the unsafe VMEXIT
+ * handlers.
+ */
vcpu->arch.l1tf_flush_l1d = false;
+ }

vcpu->stat.l1d_flush++;