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Date: Mon, 1 Apr 2024 17:59:35 +0800
From: Chao Gao <chao.gao@intel.com>
To: <isaku.yamahata@intel.com>
CC: <kvm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<isaku.yamahata@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>,
	<erdemaktas@google.com>, Sean Christopherson <seanjc@google.com>, Sagi Shahar
	<sagis@google.com>, Kai Huang <kai.huang@intel.com>, <chen.bo@intel.com>,
	<hang.yuan@intel.com>, <tina.zhang@intel.com>, Xiaoyao Li
	<xiaoyao.li@intel.com>, Sean Christopherson <sean.j.christopherson@intel.com>
Subject: Re: [PATCH v19 104/130] KVM: TDX: Add a place holder for handler of
 TDX hypercalls (TDG.VP.VMCALL)
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References: <cover.1708933498.git.isaku.yamahata@intel.com>
 <1c66bfde36f08eacbe2f5c50f88adf80e3d87ea7.1708933498.git.isaku.yamahata@intel.com>
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> static inline bool is_td_vcpu_created(struct vcpu_tdx *tdx)
> {
> 	return tdx->td_vcpu_created;
>@@ -897,6 +932,11 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu)
> 
> 	tdx_complete_interrupts(vcpu);
> 
>+	if (tdx->exit_reason.basic == EXIT_REASON_TDCALL)
>+		tdx->tdvmcall.rcx = vcpu->arch.regs[VCPU_REGS_RCX];

kvm_rcx_read()?

		
>+	else
>+		tdx->tdvmcall.rcx = 0;

RCX on TDVMCALL exit is supposed to be consumed by TDX module. I don't get why
caching it is necessary. Can tdx->tdvmcall be simply dropped?