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: <20200827160113.GA721088@rani.riverdale.lan>
Date:   Thu, 27 Aug 2020 12:01:13 -0400
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Joerg Roedel <joro@...tes.org>, 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 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?