KVM: x86/vPMU: refine kvm_pmu err msg when event creation failed

If a perf_event creation fails due to any reason of the host perf
subsystem, it has no chance to log the corresponding event for guest
which may cause abnormal sampling data in guest result. In debug mode,
this message helps to understand the state of vPMC and we may not
limit the number of occurrences but not in a spamming style.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index aa5a2597305ae82ada262121df14c6e3aafd2348..cedaa01ceb6fe0dfbcfce4ec26a680ccc290fbcf 100644 (file)
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -131,8 +131,8 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
                                                 intr ? kvm_perf_overflow_intr :
                                                 kvm_perf_overflow, pmc);
        if (IS_ERR(event)) {
-               printk_once("kvm_pmu: event creation failed %ld\n",
-                           PTR_ERR(event));
+               pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
+                           PTR_ERR(event), pmc->idx);
                return;
        }