linux-kernel - [PATCH 4.9 084/107] x86/KVM/VMX: Replace vmx_l1d_flush_always with vmx_l1d_flush

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Date:   Tue, 14 Aug 2018 19:17:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nicolai Stange <nstange@...e.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        David Woodhouse <dwmw@...zon.co.uk>
Subject: [PATCH 4.9 084/107] x86/KVM/VMX: Replace vmx_l1d_flush_always with vmx_l1d_flush_cond

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

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

From: Nicolai Stange <nstange@...e.de>

commit 427362a142441f08051369db6fbe7f61c73b3dca upstream

The vmx_l1d_flush_always static key is only ever evaluated if
vmx_l1d_should_flush is enabled. In that case however, there are only two
L1d flushing modes possible: "always" and "conditional".

The "conditional" mode's implementation tends to require more sophisticated
logic than the "always" mode.

Avoid inverted logic by replacing the 'vmx_l1d_flush_always' static key
with a 'vmx_l1d_flush_cond' one.

There is no change in functionality.

Signed-off-by: Nicolai Stange <nstange@...e.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/vmx.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -190,7 +190,7 @@ 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);
+static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_cond);
 static DEFINE_MUTEX(vmx_l1d_flush_mutex);
 
 /* Storage for pre module init parameter parsing */
@@ -264,10 +264,10 @@ static int vmx_setup_l1d_flush(enum vmx_
 	else
 		static_branch_disable(&vmx_l1d_should_flush);
 
-	if (l1tf == VMENTER_L1D_FLUSH_ALWAYS)
-		static_branch_enable(&vmx_l1d_flush_always);
+	if (l1tf == VMENTER_L1D_FLUSH_COND)
+		static_branch_enable(&vmx_l1d_flush_cond);
 	else
-		static_branch_disable(&vmx_l1d_flush_always);
+		static_branch_disable(&vmx_l1d_flush_cond);
 	return 0;
 }
 
@@ -8666,7 +8666,7 @@ static void vmx_l1d_flush(struct kvm_vcp
 	 * This code is only executed when the the flush mode is 'cond' or
 	 * 'always'
 	 */
-	if (!static_branch_unlikely(&vmx_l1d_flush_always)) {
+	if (static_branch_likely(&vmx_l1d_flush_cond)) {
 		/*
 		 * Clear the flush bit, it gets set again either from
 		 * vcpu_run() or from one of the unsafe VMEXIT