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Message-ID: <cfbe7d5a-e045-4254-8a8c-c0a8199db4b7@linux.intel.com>
Date: Thu, 18 Apr 2024 21:54:39 +0800
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Subject: Re: [PATCH v19 111/130] KVM: TDX: Implement callbacks for MSR
 operations for TDX
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
References: <cover.1708933498.git.isaku.yamahata@intel.com>
 <62f8890cb90e49a3e0b0d5946318c0267b80c540.1708933498.git.isaku.yamahata@intel.com>
From: Binbin Wu <binbin.wu@linux.intel.com>
In-Reply-To: <62f8890cb90e49a3e0b0d5946318c0267b80c540.1708933498.git.isaku.yamahata@intel.com>
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On 2/26/2024 4:26 PM, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
>
> Implements set_msr/get_msr/has_emulated_msr methods for TDX to handle
> hypercall from guest TD for paravirtualized rdmsr and wrmsr.  The TDX
> module virtualizes MSRs.  For some MSRs, it injects #VE to the guest TD
> upon RDMSR or WRMSR.  The exact list of such MSRs are defined in the spec.
>
> Upon #VE, the guest TD may execute hypercalls,
> TDG.VP.VMCALL<INSTRUCTION.RDMSR> and TDG.VP.VMCALL<INSTRUCTION.WRMSR>,
> which are defined in GHCI (Guest-Host Communication Interface) so that the
> host VMM (e.g. KVM) can virtualize the MSRs.
>
> There are three classes of MSRs virtualization.
> - non-configurable: TDX module directly virtualizes it. VMM can't
>    configure. the value set by KVM_SET_MSR_INDEX_LIST is ignored.

There is no KVM_SET_MSR_INDEX_LIST in current kvm code.
Do you mean KVM_SET_MSRS?

> - configurable: TDX module directly virtualizes it. VMM can configure at
>    the VM creation time.  The value set by KVM_SET_MSR_INDEX_LIST is used.
> - #VE case
>    Guest TD would issue TDG.VP.VMCALL<INSTRUCTION.{WRMSR,RDMSR> and
>    VMM handles the MSR hypercall. The value set by KVM_SET_MSR_INDEX_LIST
>    is used.
>