linux-kernel - [PATCH v4 3/4] KVM: VMX: Change ple

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Message-Id: <20190906021722.2095-4-peterx@redhat.com>
Date:   Fri,  6 Sep 2019 10:17:21 +0800
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Krish Sadhukhan <krish.sadhukhan@...cle.com>, peterx@...hat.com
Subject: [PATCH v4 3/4] KVM: VMX: Change ple_window type to unsigned int

The VMX ple_window is 32 bits wide, so logically it can overflow with
an int.  The module parameter is declared as unsigned int which is
good, however the dynamic variable is not.  Switching all the
ple_window references to use unsigned int.

The tracepoint changes will also affect SVM, but SVM is using an even
smaller width (16 bits) so it's always fine.

Suggested-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/x86/kvm/trace.h   | 9 +++++----
 arch/x86/kvm/vmx/vmx.c | 4 ++--
 arch/x86/kvm/vmx/vmx.h | 2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 8a7570f8c943..afe8d269c16c 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -891,14 +891,15 @@ TRACE_EVENT(kvm_pml_full,
 );
 
 TRACE_EVENT(kvm_ple_window,
-	TP_PROTO(bool grow, unsigned int vcpu_id, int new, int old),
+	TP_PROTO(bool grow, unsigned int vcpu_id, unsigned int new,
+		 unsigned int old),
 	TP_ARGS(grow, vcpu_id, new, old),
 
 	TP_STRUCT__entry(
 		__field(                bool,      grow         )
 		__field(        unsigned int,   vcpu_id         )
-		__field(                 int,       new         )
-		__field(                 int,       old         )
+		__field(        unsigned int,       new         )
+		__field(        unsigned int,       old         )
 	),
 
 	TP_fast_assign(
@@ -908,7 +909,7 @@ TRACE_EVENT(kvm_ple_window,
 		__entry->old            = old;
 	),
 
-	TP_printk("vcpu %u: ple_window %d (%s %d)",
+	TP_printk("vcpu %u: ple_window %u (%s %u)",
 	          __entry->vcpu_id,
 	          __entry->new,
 	          __entry->grow ? "grow" : "shrink",
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 42ed3faa6af8..b172b675d420 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5227,7 +5227,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 static void grow_ple_window(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	int old = vmx->ple_window;
+	unsigned int old = vmx->ple_window;
 
 	vmx->ple_window = __grow_ple_window(old, ple_window,
 					    ple_window_grow,
@@ -5242,7 +5242,7 @@ static void grow_ple_window(struct kvm_vcpu *vcpu)
 static void shrink_ple_window(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	int old = vmx->ple_window;
+	unsigned int old = vmx->ple_window;
 
 	vmx->ple_window = __shrink_ple_window(old, ple_window,
 					      ple_window_shrink,
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 82d0bc3a4d52..64d5a4890aa9 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -253,7 +253,7 @@ struct vcpu_vmx {
 	struct nested_vmx nested;
 
 	/* Dynamic PLE window. */
-	int ple_window;
+	unsigned int ple_window;
 	bool ple_window_dirty;
 
 	bool req_immediate_exit;
-- 
2.21.0