linux-kernel - Re: [PATCH 41/70] x86/sev-es: Add Runtime #VC Exception Handler

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: <20200319193813.GE611@suse.de>
Date:   Thu, 19 Mar 2020 20:38:13 +0100
From:   Joerg Roedel <jroedel@...e.de>
To:     Andy Lutomirski <luto@...nel.org>
Cc:     Joerg Roedel <joro@...tes.org>, X86 ML <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Hellstrom <thellstrom@...are.com>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>,
        kvm list <kvm@...r.kernel.org>,
        Linux Virtualization <virtualization@...ts.linux-foundation.org>
Subject: Re: [PATCH 41/70] x86/sev-es: Add Runtime #VC Exception Handler

On Thu, Mar 19, 2020 at 11:43:20AM -0700, Andy Lutomirski wrote:
> Or future generations could have enough hardware support for debugging
> that #DB doesn't need to be intercepted or can be re-injected
> correctly with the #DB vector.

Yeah, the problem is, the GHCB spec suggests the single-step-over-iret
way to re-enable the NMI window and requires intercepting #DB for it. So
the hypervisor probably still has to intercept it, even when debug
support is added some day. I need to think more about this.

Regards,

	Joerg