Re: [PATCH v8 5/5] x86/tdx: Add Quote generation support

[Guorui Yu]

Hi Dave,

Kindly ping for any comments here?

Sincerely,
Guorui

在 2022/8/9 14:20, Guorui Yu 写道:
> To my opinion, virtio-vsock is a wonderful way to achieve the 
> comunication between the host and the guest under traditional scenario.
>
> But from secuirty perspective, virtio-vsock itself may involve too much 
> of components, which may lead to considerable attack surfaces. In order 
> for virtio to work properly, the guest must maintain several vrings 
> placed in shared memory, which in turn depends on swiotlb in current 
> codebase. As this flow is NOT designed for confidential scenario, there 
> are some on-going/existing works on virtio hardening [1] [2] [3].
>
>  > Do we *REALLY* need specific driver functionality for this?  For
>  > instance, is there no existing virtio device that can send blobs back
>  > and forth?
>
> And we may indeed have use cases where virtio is not used at all, such 
> as when we consider Intel-TDX/AMD-SNP protected VMs as a SGX enclave 
> replacement. In such use cases, end users may expect a smaller 
> dependency on the GetQuote interface. It doesn't seem natural that the 
> GetQuote interface cannot be used because virtio-vsock is disabled (via 
> kernel compile options or the upcoming device-filter), since GetQuote 
> doesn't inherently depend on it.
>
> Thanks,
> Guorui
>
> [1] 
> https://lore.kernel.org/lkml/20210603004133.4079390-1-ak@xxxxxxxxxxxxxxx/
> [2] https://lore.kernel.org/lkml/20211012065227.9953-1-jasowang@xxxxxxxxxx/
> [3] 
> https://lore.kernel.org/linux-iommu/d2ae0b1d-332b-42a1-87bf-7da2b749cac2@xxxxxxxxxxxxxxxxx/