linux-kernel - Re: [PATCH v12 20/22] x86/virt/tdx: Allow SEAMCALL to handle #UD and #GP

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: <20230630102141.GA2534364@hirez.programming.kicks-ass.net>
Date:   Fri, 30 Jun 2023 12:21:41 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Huang, Kai" <kai.huang@...el.com>
Cc:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "Raj, Ashok" <ashok.raj@...el.com>,
        "Hansen, Dave" <dave.hansen@...el.com>,
        "david@...hat.com" <david@...hat.com>,
        "bagasdotme@...il.com" <bagasdotme@...il.com>,
        "Luck, Tony" <tony.luck@...el.com>,
        "ak@...ux.intel.com" <ak@...ux.intel.com>,
        "Wysocki, Rafael J" <rafael.j.wysocki@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Christopherson,, Sean" <seanjc@...gle.com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
        "Chatre, Reinette" <reinette.chatre@...el.com>,
        "Yamahata, Isaku" <isaku.yamahata@...el.com>,
        "nik.borisov@...e.com" <nik.borisov@...e.com>,
        "hpa@...or.com" <hpa@...or.com>, "Shahar, Sagi" <sagis@...gle.com>,
        "imammedo@...hat.com" <imammedo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>, "Gao, Chao" <chao.gao@...el.com>,
        "Brown, Len" <len.brown@...el.com>,
        "sathyanarayanan.kuppuswamy@...ux.intel.com" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        "Huang, Ying" <ying.huang@...el.com>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH v12 20/22] x86/virt/tdx: Allow SEAMCALL to handle #UD and
 #GP

On Fri, Jun 30, 2023 at 12:07:00PM +0200, Peter Zijlstra wrote:
> On Thu, Jun 29, 2023 at 10:33:38AM +0000, Huang, Kai wrote:

> > Looking at the later versions of TDX spec (with TD live migration, etc), it
> > seems they are already using R12-R13 as SEAMCALL output:
> > 
> > https://cdrdv2.intel.com/v1/dl/getContent/733579
> 
> Urgh.. I think I read an older versio because I got bleeding eyes from
> all this colour coded crap.
> 
> All this red is unreadable :-( Have they been told about the glories of
> TeX and diff ?
> 
> > E.g., 6.3.15. NEW: TDH.IMPORT.MEM Leaf
> > 
> > It uses R12 and R13 as input.
> 
> 12 and 14. They skipped 13 for some mysterious raisin.

Things like TDH.SERVTD.BIND do use R13.

> But also, 10,11 are frequently used as input with this new stuff, which
> already suggests the setup from your patches is not tenable.


TDG.SERVTD.RD *why* can't they pass that TD_UUID as a pointer? Using *4*
registers like that is quite insane.

TDG.VP.ENTER :-(((( that has b,15,si,di as additional output.

That means there's not a single register left unused. Can we still get
this changed, please?!?