Re: [RFC PATCH 64/67] KVM: TDX: Add "basic" support for building and running Trust Domains

From: Sean Christopherson
Date: Fri Jun 11 2021 - 11:23:43 EST


On Thu, Jun 10, 2021, Erdem Aktas wrote:
> Hi Isaku,
>
> I know you are going to submit a set of new patch series so here are
> few feedbacks thatI have encounter:
>
>
> KVM_TDX_INIT_VM has a parameter that user space VMM can provide the
> CPUID entries but it is not clear if any of those entries are
> mandatory. If userspace VMM does not provide guest_supported_xcr0 and
> guest_supported_xss, TDX init will fail as their default values are
> set to 0.
>
> It is expected but would be nice to document (or return an error
> message with more information) that KVM_CAP_X2APIC_API and
> KVM_IRQCHIP_SPLIT CAPS need to be enabled.
>
> When CPUID entries are queried from KVM (using
> KVM_GET_SUPPORTED_CPUID) and provided back to the KVM_TDX_INIT_VM,
> the default GPAW size requires 5 level SEPT but KVM still tries to
> create 4 level SEPT and fails to add private pages. Error messages are
> also not very helpful to figure out what was happening.

Please trim your replies and try to avoid top-posting. Thanks for the input!

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