linux-kernel - [PATCH 2/2] KVM: VMX: Don't expose PLE enable if there is no hardware support

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Message-Id: <1506494062-25533-2-git-send-email-wanpeng.li@hotmail.com>
Date:   Tue, 26 Sep 2017 23:34:22 -0700
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Wanpeng Li <wanpeng.li@...mail.com>
Subject: [PATCH 2/2] KVM: VMX: Don't expose PLE enable if there is no hardware support

From: Wanpeng Li <wanpeng.li@...mail.com>

PLE_Window: Software can configure this field as an upper bound on the amount of time
a guest is allowed to execute in a PAUSE LOOP.

KVM doesn't expose the PLE capability to the L1 hypervsior, however, ple_window still
shows the default value on L1 hypervsior. This patch fixes it by clearing all the
PLE related module parameter if there is no PLE capability.

Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>
---
 arch/x86/kvm/vmx.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c83d28b..4d4f9b4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6781,8 +6781,13 @@ static __init int hardware_setup(void)
 	if (enable_ept && !cpu_has_vmx_ept_2m_page())
 		kvm_disable_largepages();
 
-	if (!cpu_has_vmx_ple())
+	if (!cpu_has_vmx_ple()) {
 		ple_gap = 0;
+		ple_window = 0;
+		ple_window_grow = 0;
+		ple_window_max = 0;
+		ple_window_shrink = 0;
+	}
 
 	if (!cpu_has_vmx_apicv()) {
 		enable_apicv = 0;
-- 
2.7.4