If KVM cannot find an exact match for a requested CPUID leaf, the code will try to find the closest match instead of simply confessing it's failure. The heuristic is on one hand wrong nowadays, since it does not take the KVM CPUID leaves (0x400000xx) into account. On the other hand the callers of this function can all deal with the no-match situation. So lets remove this code, as it serves no purpose. This fixes a crash of newer Linux kernels as KVM guests on AMD Bulldozer CPUs, where bogus values were returned in response to a CPUID intercept. CC: <stable@xxxxxxxxxx> [2.6.38] Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> --- arch/x86/kvm/x86.c | 6 ------ 1 files changed, 0 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6e86cec..625143f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4959,12 +4959,6 @@ struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, best = e; break; } - /* - * Both basic or both extended? - */ - if (((e->function ^ function) & 0x80000000) == 0) - if (!best || e->function > best->function) - best = e; } return best; } -- 1.6.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
