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Date:   Tue, 25 Aug 2020 11:22:24 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Borislav Petkov <bp@alien8.de>
Cc:     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: <20200825092224.GF3319@8bytes.org>
References: <20200824085511.7553-1-joro@8bytes.org>
 <20200824085511.7553-3-joro@8bytes.org>
 <20200824104451.GA4732@zn.tnic>
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On Mon, Aug 24, 2020 at 12:44:51PM +0200, Borislav Petkov wrote:
> On Mon, Aug 24, 2020 at 10:53:57AM +0200, Joerg Roedel wrote:
> >  static inline void __unused_size_checks(void)
> >  {
> > -	BUILD_BUG_ON(sizeof(struct vmcb_save_area) != 0x298);
> > +	BUILD_BUG_ON(sizeof(struct vmcb_save_area) != 1032);
> >  	BUILD_BUG_ON(sizeof(struct vmcb_control_area) != 256);
> > +	BUILD_BUG_ON(sizeof(struct ghcb) != 4096);
> 
> Could those naked numbers be proper, meaningfully named defines?

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.

Regards,

	Joerg