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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pRyfy-009hH0-2l; Tue, 14 Feb 2023 17:01:49 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id C14723033F7; Tue, 14 Feb 2023 13:46:45 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A9F5323BC86ED; Tue, 14 Feb 2023 13:46:45 +0100 (CET) Date: Tue, 14 Feb 2023 13:46:45 +0100 From: Peter Zijlstra To: Kai Huang 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: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: CD1C880041 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: 1iuxsrhy4qmwtatxdx1cpmdpkwuckr88 X-HE-Tag: 1676394115-344205 X-HE-Meta: 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 ykt0L25U amxy6Mmb64C8o198hjYG5EQ9qZ6nxBYQIUFsLF+ioLjkAnbIyMmMLeRFxWmMEHpD0MLswfCobfhTDVIWBMYa7U9xnzynIC2CsIt4c0O+K34IaUnDo4Rdv/Nf/GODS+aWA5YlZLLo65QtkkIjb6EN3nBMgwZ4xvPxl6TJT X-Bogosity: Ham, tests=bogofilter, spamicity=0.001002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.