Re: [PATCH v7 11/14] KVM: Register/unregister the guest private memory regions

Gupta, Pankaj
2022-07-20T15:32:19Z

>>>>> +bool __weak kvm_arch_private_mem_supported(struct kvm *kvm)
>>>>> +{
>>>>> + return false;
>>>>> +}
>>>>
>>>> Does this function has to be overriden by SEV and TDX to support the private
>>>> regions?
>>>
>>> Yes it should be overridden by architectures which want to support it.
>>
>> o.k
>>>
>>>>
>>>>> +
>>>>> static int check_memory_region_flags(const struct kvm_user_mem_region *mem)
>>>>> {
>>>>> u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
>>>>> @@ -4689,6 +4729,22 @@ static long kvm_vm_ioctl(struct file *filp,
>>>>> r = kvm_vm_ioctl_set_memory_region(kvm, &mem);
>>>>> break;
>>>>> }
>>>>> +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
>>>>> + case KVM_MEMORY_ENCRYPT_REG_REGION:
>>>>> + case KVM_MEMORY_ENCRYPT_UNREG_REGION: {
>>>>> + struct kvm_enc_region region;
>>>>> +
>>>>> + if (!kvm_arch_private_mem_supported(kvm))
>>>>> + goto arch_vm_ioctl;
>>>>> +
>>>>> + r = -EFAULT;
>>>>> + if (copy_from_user(&region, argp, sizeof(region)))
>>>>> + goto out;
>>>>> +
>>>>> + r = kvm_vm_ioctl_set_encrypted_region(kvm, ioctl, &region);
>>>>
>>>> this is to store private region metadata not only the encrypted region?
>>>
>>> Correct.
>>
>> Sorry for not being clear, was suggesting name change of this function from:
>> "kvm_vm_ioctl_set_encrypted_region" to "kvm_vm_ioctl_set_private_region"
>
> Though I don't have strong reason to change it, I'm fine with this and

Yes, no strong reason, just thought "kvm_vm_ioctl_set_private_region"
would depict the actual functionality :)

> this name matches the above kvm_arch_private_mem_supported perfectly.
BTW could not understand this, how "kvm_vm_ioctl_set_encrypted_region"
matches "kvm_arch_private_mem_supported"?

Thanks,
Pankaj