Re: [RFC PATCH v5 102/104] KVM: TDX: Add methods to ignore accesses to CPU state

[Xiaoyao Li]

On 3/5/2022 3:49 AM, isaku.yamahata@xxxxxxxxx wrote:
> From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>
> TDX protects TDX guest state from VMM.  Implements to access methods for
> TDX guest state to ignore them or return zero.

...

> +void tdx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
> +{
> +	kvm_register_mark_available(vcpu, reg);
> +	switch (reg) {
> +	case VCPU_REGS_RSP:
> +	case VCPU_REGS_RIP:
> +	case VCPU_EXREG_PDPTR:
> +	case VCPU_EXREG_CR0:
> +	case VCPU_EXREG_CR3:
> +	case VCPU_EXREG_CR4:
> +		break;
> +	default:
> +		KVM_BUG_ON(1, vcpu->kvm);
> +		break;
> +	}
> +}

Isaku,

We missed one case that some GPRs are accessible by KVM/userspace for 
TDVMCALL exit.