On 21/02/20 16:23, Sean Christopherson wrote:
>
> I'm guessing no VMM actually uses this ioctl(), e.g. neither Qemu or CrosVM
> use it, which is why the broken behavior has gone unnoticed. Don't suppose
> you'd want to write a selftest to hammer KVM_{SET,GET}_CPUID2?
>
> int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
> struct kvm_cpuid2 *cpuid,
> struct kvm_cpuid_entry2 __user *entries)
> {
> if (cpuid->nent < vcpu->arch.cpuid_nent)
> return -E2BIG;
>
> if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
> vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
> return -EFAULT;
>
> cpuid->nent = vcpu->arch.cpuid_nent;
>
> return 0;
> }
I would just drop KVM_GET_CPUID2 altogether and see if someone complains.
Paolo
