Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Arvind Sankar <nivedita@alum.mit.edu>
Date:   Thu, 27 Aug 2020 12:01:13 -0400
To:     Borislav Petkov <bp@alien8.de>
Cc:     Joerg Roedel <joro@8bytes.org>, x86@kernel.org,
        Joerg Roedel <jroedel@suse.de>,
        Tom Lendacky <thomas.lendacky@amd.com>, hpa@zytor.com,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Jiri Slaby <jslaby@suse.cz>,
        Dan Williams <dan.j.williams@intel.com>,
        Juergen Gross <jgross@suse.com>,
        Kees Cook <keescook@chromium.org>,
        David Rientjes <rientjes@google.com>,
        Cfir Cohen <cfir@google.com>,
        Erdem Aktas <erdemaktas@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mike Stunes <mstunes@vmware.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Martin Radev <martin.b.radev@gmail.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v6 02/76] KVM: SVM: Add GHCB definitions
Message-ID: <20200827160113.GA721088@rani.riverdale.lan>
References: <20200824085511.7553-1-joro@8bytes.org>
 <20200824085511.7553-3-joro@8bytes.org>
 <20200824104451.GA4732@zn.tnic>
 <20200825092224.GF3319@8bytes.org>
 <20200825110446.GC12107@zn.tnic>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20200825110446.GC12107@zn.tnic>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Aug 25, 2020 at 01:04:46PM +0200, Borislav Petkov wrote:
> On Tue, Aug 25, 2020 at 11:22:24AM +0200, Joerg Roedel wrote:
> > I don't think so, if I look at the history of these checks their whole
> > purpose seems to be to alert the developer/maintainer when their size
> > changes and that they might not fit on the stack anymore. But that is
> > taken care of in patch 1.
> 
> Why? What's wrong with:
> 
> 	BUILD_BUG_ON(sizeof(struct vmcb_save_area) != VMCB_SAVE_AREA_SIZE);
> 	BUILD_BUG_ON(sizeof(struct vmcb_control_area) != VMCB_CONTROL_AREA_SIZE);
> 	BUILD_BUG_ON(sizeof(struct ghcb) != PAGE_SIZE);
> 
> ?
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

Wouldn't we rather just remove the checks?