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X-IronPort-AV: E=McAfee;i="6600,9927,10754"; a="361865551" X-IronPort-AV: E=Sophos;i="6.01,165,1684825200"; d="scan'208";a="361865551" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2023 04:55:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10754"; a="711019721" X-IronPort-AV: E=Sophos;i="6.01,165,1684825200"; d="scan'208";a="711019721" Received: from rajritu-mobl2.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.47.187]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2023 04:55:24 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 57DD21095C8; Wed, 28 Jun 2023 14:55:21 +0300 (+03) Date: Wed, 28 Jun 2023 14:55:21 +0300 From: "kirill.shutemov@linux.intel.com" To: "Huang, Kai" Cc: "kvm@vger.kernel.org" , "Raj, Ashok" , "Huang, Ying" , "Hansen, Dave" , "david@redhat.com" , "bagasdotme@gmail.com" , "ak@linux.intel.com" , "Wysocki, Rafael J" , "linux-kernel@vger.kernel.org" , "Chatre, Reinette" , "Christopherson,, Sean" , "pbonzini@redhat.com" , "mingo@redhat.com" , "Yamahata, Isaku" , "nik.borisov@suse.com" , "tglx@linutronix.de" , "Luck, Tony" , "linux-mm@kvack.org" , "hpa@zytor.com" , "peterz@infradead.org" , "imammedo@redhat.com" , "Shahar, Sagi" , "bp@alien8.de" , "Brown, Len" , "Gao, Chao" , "sathyanarayanan.kuppuswamy@linux.intel.com" , "Williams, Dan J" , "x86@kernel.org" Subject: Re: [PATCH v12 07/22] x86/virt/tdx: Add skeleton to enable TDX on demand Message-ID: <20230628115521.bo7x6lhonsmyvr7v@box.shutemov.name> References: <104d324cd68b12e14722ee5d85a660cccccd8892.1687784645.git.kai.huang@intel.com> <20230627095012.ln47s62pqzdrnb7x@box.shutemov.name> <20230627121853.ek5zr7sfiezfkfyj@box.shutemov.name> <9361abfa9bf22c2a1a4b25e5495bcccc5b8dcd43.camel@intel.com> <7b61715ad35d7b9916f55df72378e02e62c5cc4e.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7b61715ad35d7b9916f55df72378e02e62c5cc4e.camel@intel.com> X-Rspam-User: X-Stat-Signature: 1f1rpjo3s1p7uq95iurou31rcgaieuor X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 676FD14001C X-HE-Tag: 1687953334-454353 X-HE-Meta: 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 2q8jOp2b Hg8ROLp9sEwD5xw9BGxbKX4S9+eYBJEmIUDZ2w4/7wee/GITkgHbyBnbTTXrw8Y0U1nXH4+y6WxsdlDzBpRqblw6BHpsY0O0AXpfUp4uvJhjqfVqW3KlHEUpPCfI0mlaKcX/lnhHIT1KsWQVksJEcsZlVMvpq2sX3DuQ6 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jun 28, 2023 at 12:28:12AM +0000, Huang, Kai wrote: > On Tue, 2023-06-27 at 22:37 +0000, Huang, Kai wrote: > > > > > > > > +/* > > > > + * Do the module global initialization if not done yet. > > > > + * It's always called with interrupts and preemption disabled. > > > > + */ > > > > > > If interrupts are always disabled why do you need _irqsave()? > > > > > > > I'll remove the _irqsave(). > > > > AFAICT Isaku preferred this for additional security, but this is not > > necessary. > > > > > > Damn. I think we can change the comment to say this function is called with > preemption being disabled, but _can_ be called with interrupt disabled. And we > keep using the _irqsave() version. > > /* > * Do the module global initialization if not done yet. It's always > * called with preemption disabled and can be called with interrupts > * disabled. > */ > > This allows a use case that the caller simply wants to call some SEAMCALL on > local cpu, e.g., IOMMU code may just use below to get some TDX-IO information: > > preempt_disable(); > vmxon(); > tdx_cpu_enable(); > SEAMCALL; > vmxoff(); > preempt_enable(); > > Are you OK with this? Is it hypothetical use-case? If so, I would rather keep it simple for now and adjust in the future if needed. -- Kiryl Shutsemau / Kirill A. Shutemov