On Wed, 2022-06-22 at 10:57 +0100, Paul Durrant wrote: > +void kvm_xen_set_cpuid(struct kvm_vcpu *vcpu) > +{ > + u32 base = 0; > + u32 function; > + > + vcpu->arch.xen.tsc_info_1 = NULL; > + vcpu->arch.xen.tsc_info_2 = NULL; > + > + for_each_possible_hypervisor_cpuid_base(function) { > + struct kvm_cpuid_entry2 *entry = kvm_find_cpuid_entry(vcpu, function, 0); > + > + if (entry && > + entry->ebx == XEN_CPUID_SIGNATURE_EBX && > + entry->ecx == XEN_CPUID_SIGNATURE_ECX && > + entry->edx == XEN_CPUID_SIGNATURE_EDX) { > + base = function; > + break; > + } > + } Please make it return if entry->eax < 3 here. There probably aren't any *good* reasons why a leaf at 0x40000x03 would exist and belong to some other entity (Hyper-V, etc.). Those other extra ranges of CPUID are generally aligned at multiples of 0x100, not just the *next* available leaf. But I don't care. Unless eax on the main Xen leaf is 3 or more, the leaf at N+3 isn't yours to reason about :) > + if (!base) > + return; > + > + function = base | XEN_CPUID_LEAF(3); > + vcpu->arch.xen.tsc_info_1 = kvm_find_cpuid_entry(vcpu, function, 1); > + vcpu->arch.xen.tsc_info_2 = kvm_find_cpuid_entry(vcpu, function, 2); > +} > +
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