[PATCH 3.12 013/123] Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS

From: Jiri Slaby
Date: Wed Oct 28 2015 - 10:39:44 EST

From: Dirk MÃller <dmueller@xxxxxxxx>

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


commit d2922422c48df93f3edff7d872ee4f3191fefb08 upstream.

The cpu feature flags are not ever going to change, so warning
everytime can cause a lot of kernel log spam
(in our case more than 10GB/hour).

The warning seems to only occur when nested virtualization is
enabled, so it's probably triggered by a KVM bug. This is a
sensible and safe change anyway, and the KVM bug fix might not
be suitable for stable releases anyway.

Signed-off-by: Dirk Mueller <dmueller@xxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
arch/x86/kvm/svm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2996635196d3..d1a065ec683f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -496,7 +496,7 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);

if (svm->vmcb->control.next_rip != 0) {
- WARN_ON(!static_cpu_has(X86_FEATURE_NRIPS));
+ WARN_ON_ONCE(!static_cpu_has(X86_FEATURE_NRIPS));
svm->next_rip = svm->vmcb->control.next_rip;


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