linux-kernel - [PATCH] KVM: VMX: check match table

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Date:   Mon, 25 Sep 2017 21:25:38 -0700
From:   Nick Desaulniers <nick.desaulniers@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     josh@...htriplett.org, kay@...y.org, avi@...hat.com,
        Nick Desaulniers <nick.desaulniers@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH] KVM: VMX: check match table

Fixes the warning:
arch/x86/kvm/vmx.c:64:32: warning: variable 'vmx_cpu_id' is not needed
and will not be emitted [-Wunneeded-internal-declaration]``

Other callers of MODULE_DEVICE_TABLE() seem to check their second
argument during driver init with the x86_match_cpu() function, if their
first argument to MODULE_DEVICE_TABLE() is x86cpu.  The documentation
for x86_match_cpu() seems to agree.

Suggested-by: Josh Triplett <josh@...htriplett.org>
Signed-off-by: Nick Desaulniers <nick.desaulniers@...il.com>
---
 arch/x86/kernel/cpu/match.c | 2 +-
 arch/x86/kvm/vmx.c          | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index e42117d5f4d7..fb1aeafa5cc7 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -5,7 +5,7 @@
 #include <linux/slab.h>
 
 /**
- * x86_match_cpu - match current CPU again an array of x86_cpu_ids
+ * x86_match_cpu - match current CPU against an array of x86_cpu_ids
  * @match: Pointer to array of x86_cpu_ids. Last entry terminated with
  *         {}.
  *
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6970249c09fc..e1a00b130935 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -12074,7 +12074,12 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 
 static int __init vmx_init(void)
 {
-	int r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx),
+	int r;
+
+	if (!x86_match_cpu(vmx_cpu_id))
+		return -ENODEV;
+
+	r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx),
                      __alignof__(struct vcpu_vmx), THIS_MODULE);
 	if (r)
 		return r;
-- 
2.11.0