Date:   Tue, 14 Feb 2023 13:46:45 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Kai Huang <kai.huang@intel.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-mm@kvack.org, dave.hansen@intel.com, tglx@linutronix.de,
        seanjc@google.com, pbonzini@redhat.com, dan.j.williams@intel.com,
        rafael.j.wysocki@intel.com, kirill.shutemov@linux.intel.com,
        ying.huang@intel.com, reinette.chatre@intel.com,
        len.brown@intel.com, tony.luck@intel.com, ak@linux.intel.com,
        isaku.yamahata@intel.com, chao.gao@intel.com,
        sathyanarayanan.kuppuswamy@linux.intel.com, david@redhat.com,
        bagasdotme@gmail.com, sagis@google.com, imammedo@redhat.com
Subject: Re: [PATCH v9 04/18] x86/virt/tdx: Add skeleton to initialize TDX on
 demand
Message-ID: <Y+uCtZ7itiNsbR4j@hirez.programming.kicks-ass.net>
References: <cover.1676286526.git.kai.huang@intel.com>
 <eb565156d84e35a846a886025513a712f2ac2f83.1676286526.git.kai.huang@intel.com>
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On Tue, Feb 14, 2023 at 12:59:11AM +1300, Kai Huang wrote:
> Use a state machine protected by mutex to make sure the initialization
> will only be done once, as tdx_enable() can be called multiple times
> (i.e. KVM module can be reloaded) and be called concurrently by other
> kernel components in the future.

I still object to doing tdx_enable() at kvm module load.

kvm.ko gets loaded unconditionally on boot, even if I then never use
kvm.

This stuff needs to be done when an actual VM is created, not before.