Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 25 Feb 2022 02:54:13 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        luto@kernel.org, peterz@infradead.org,
        sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com,
        ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com,
        hpa@zytor.com, jgross@suse.com, jmattson@google.com,
        joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org,
        pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com,
        tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com,
        thomas.lendacky@amd.com, brijesh.singh@amd.com, x86@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCHv4 05/30] x86/tdx: Extend the confidential computing API
 to support TDX guests
Message-ID: <20220224235413.lrzczn7re4mfdkup@black.fi.intel.com>
References: <20220224155630.52734-1-kirill.shutemov@linux.intel.com>
 <20220224155630.52734-6-kirill.shutemov@linux.intel.com>
 <d51dc9c2-61e5-c8dd-e358-e4ab3d5429ac@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <d51dc9c2-61e5-c8dd-e358-e4ab3d5429ac@intel.com>
Precedence: bulk

On Thu, Feb 24, 2022 at 09:54:16AM -0800, Dave Hansen wrote:
> 
> This left me wondering two things.  First, why this bothers storing
> 'gpa_width' when it's only used to generate a mask?  Why not just store
> the mask in the structure?

It was needed when tdx_shared_mask() was a thing. It takes a pair of
fresh eyes to break the inertia.

> Second, why have the global 'td_info' instead of just declaring it on
> the stack.  It is only used within a single function.  Having it on the
> stack is *REALLY* nice because the code ends up looking like:
> 
> 	struct foo foo;
> 	get_info(&foo);
> 	cc_set_bar(foo.bar);
> 
> The dependencies and scope are just stupidly obvious if you do that.

Okay, I will rework it with plain gpa_width on stack and get_info(&gpa_width);
Attributes will be needed after core enabling, so I will drop it from
here.

-- 
 Kirill A. Shutemov