linux-kernel - Re: [PATCH v6 02/76] KVM: SVM: Add GHCB definitions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200825092224.GF3319@8bytes.org>
Date:   Tue, 25 Aug 2020 11:22:24 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     x86@...nel.org, Joerg Roedel <jroedel@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>, hpa@...or.com,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        David Rientjes <rientjes@...gle.com>,
        Cfir Cohen <cfir@...gle.com>,
        Erdem Aktas <erdemaktas@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mike Stunes <mstunes@...are.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Martin Radev <martin.b.radev@...il.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH v6 02/76] KVM: SVM: Add GHCB definitions

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