Current implementation keeps userspace input of CPUID configuration and
cpuid->nent even if kvm_update_cpuid() fails. Reset vcpu->arch.cpuid_nent
to 0 for the case of failure as a simple fix.
Besides, update the doc to explicitly state that if IOCTL SET_CPUID*
fail KVM gives no gurantee that previous valid CPUID configuration is
kept.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <
20200708065054.19713-2-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Defines the vcpu responses to the cpuid instruction. Applications
should use the KVM_SET_CPUID2 ioctl if available.
+Note, when this IOCTL fails, KVM gives no guarantees that previous valid CPUID
+configuration (if there is) is not corrupted. Userspace can get a copy of the
+resulting CPUID configuration through KVM_GET_CPUID2 in case.
+
::
struct kvm_cpuid_entry {
kvm_apic_set_version(vcpu);
kvm_x86_ops.cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);
+ if (r)
+ vcpu->arch.cpuid_nent = 0;
kvfree(cpuid_entries);
out:
kvm_apic_set_version(vcpu);
kvm_x86_ops.cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);
+ if (r)
+ vcpu->arch.cpuid_nent = 0;
out:
return r;
}