linux-kernel - Re: [PATCH v3 05/21] x86/virt/tdx: Detect P-SEAMLDR and TDX module

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 for Android: free password hash cracker in your pocket

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

Message-ID: <98af78402861b1982607c5fd14b0c89403c042a6.camel@intel.com>
Date:   Wed, 27 Apr 2022 12:01:25 +1200
From:   Kai Huang <kai.huang@...el.com>
To:     Dave Hansen <dave.hansen@...el.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com, len.brown@...el.com,
        tony.luck@...el.com, rafael.j.wysocki@...el.com,
        reinette.chatre@...el.com, dan.j.williams@...el.com,
        peterz@...radead.org, ak@...ux.intel.com,
        kirill.shutemov@...ux.intel.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com,
        isaku.yamahata@...el.com
Subject: Re: [PATCH v3 05/21] x86/virt/tdx: Detect P-SEAMLDR and TDX module

On Tue, 2022-04-26 at 13:56 -0700, Dave Hansen wrote:
> On 4/5/22 21:49, Kai Huang wrote:
> > The P-SEAMLDR (persistent SEAM loader) is the first software module that
> > runs in SEAM VMX root, responsible for loading and updating the TDX
> > module.  Both the P-SEAMLDR and the TDX module are expected to be loaded
> > before host kernel boots.
> 
> Why bother with the P-SEAMLDR here at all?  The kernel isn't loading the
> TDX module in this series.  Why not just call into the TDX module directly?

It's not absolutely needed in this series.  I choose to detect P-SEAMLDR because
detecting it can also detect the TDX module, and eventually we will need to
support P-SEAMLDR because the TDX module runtime update uses P-SEAMLDR's
SEAMCALL to do that.

Also, even for this series, detecting the P-SEAMLDR allows us to provide the P-
SEAMLDR information to user at a basic level in dmesg:

[..] tdx: P-SEAMLDR: version 0x0, vendor_id: 0x8086, build_date: 20211209,
build_num 160, major 1, minor 0

This may be useful to users, but it's not a hard requirement for this series.


-- 
Thanks,
-Kai