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Date:   Wed, 18 Oct 2023 11:39:14 +0300
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Subject: Re: [PATCH v14 07/23] x86/virt/tdx: Add skeleton to enable TDX on
 demand
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To:     "Huang, Kai" <kai.huang@intel.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc:     "sathyanarayanan.kuppuswamy@linux.intel.com" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        "david@redhat.com" <david@redhat.com>,
        "bagasdotme@gmail.com" <bagasdotme@gmail.com>,
        "ak@linux.intel.com" <ak@linux.intel.com>,
        "kirill.shutemov@linux.intel.com" <kirill.shutemov@linux.intel.com>,
        "Christopherson,, Sean" <seanjc@google.com>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "Yamahata, Isaku" <isaku.yamahata@intel.com>,
        "Luck, Tony" <tony.luck@intel.com>,
        "hpa@zytor.com" <hpa@zytor.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "Shahar, Sagi" <sagis@google.com>,
        "imammedo@redhat.com" <imammedo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>, "Gao, Chao" <chao.gao@intel.com>,
        "rafael@kernel.org" <rafael@kernel.org>,
        "Brown, Len" <len.brown@intel.com>,
        "Huang, Ying" <ying.huang@intel.com>,
        "Williams, Dan J" <dan.j.williams@intel.com>,
        "x86@kernel.org" <x86@kernel.org>
References: <cover.1697532085.git.kai.huang@intel.com>
 <4fd10771907ae276548140cf7f8746e2eb38821c.1697532085.git.kai.huang@intel.com>
 <ea983252-0219-46a7-99be-5a8d22049fd6@suse.com>
 <a0389bcb3fa4cd1f02bff94090f302b87d98a2e3.camel@intel.com>
From:   Nikolay Borisov <nik.borisov@suse.com>
In-Reply-To: <a0389bcb3fa4cd1f02bff94090f302b87d98a2e3.camel@intel.com>
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On 18.10.23 г. 11:29 ч., Huang, Kai wrote:
>   
>>> +/*
>>> + * Do the module global initialization once and return its result.
>>> + * It can be done on any cpu.  It's always called with interrupts
>>> + * disabled.
>>> + */
>>> +static int try_init_module_global(void)
>>> +{
>>
>> Any particular reason why this function is not called from the tdx
>> module's tdx_init? It's global and must be called once when the module
>> is initialised. Subsequently kvm which is supposed to call
>> tdx_cpu_enable() must be sequenced _after_ tdx which shouldn't be that
>> hard, no? This will eliminate the spinlock as well.
>>
> 
> Do you mean early_initcall(tdx_init)?
> 
> Because it requires VMXON being done to do SEAMCALL.  For now only KVM does
> VMXON.
> 

Right, then would it not make more sense too have this code as part of 
the KVM bringup of TDX. In fact by keeping the 2 series separate you 
might be adding complexity. What is the initial motivation to keep those 
patches out of the KVM tdx host series support?