linux-kernel - Re: [PATCH v3 08/21] x86/virt/tdx: Do logical-cpu scope TDX module initialization

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Message-ID: <4bff50c3-4065-65a3-b698-28f2391bb776@linux.intel.com>
Date:   Sat, 23 Apr 2022 18:27:43 -0700
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Kai Huang <kai.huang@...el.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com, dave.hansen@...el.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, isaku.yamahata@...el.com
Subject: Re: [PATCH v3 08/21] x86/virt/tdx: Do logical-cpu scope TDX module
 initialization



On 4/5/22 9:49 PM, Kai Huang wrote:
> Logical-cpu scope initialization requires calling TDH.SYS.LP.INIT on all
> BIOS-enabled cpus, otherwise the TDH.SYS.CONFIG SEAMCALL will fail.

IIUC, this change handles logical CPU initialization part of TDX module
initialization. So why talk about TDH.SYS.CONFIG failure here? Are they
related?

> TDH.SYS.LP.INIT can be called concurrently on all cpus.

IMO, if you move the following paragraph to the beginning, it is easier
to understand "what" and "why" part of this change.
> 
> Following global initialization, do the logical-cpu scope initialization
> by calling TDH.SYS.LP.INIT on all online cpus.  Whether all BIOS-enabled
> cpus are online is not checked here for simplicity.  The caller of
> tdx_init() should guarantee all BIOS-enabled cpus are online.

Include specification reference for TDX module initialization and
TDH.SYS.LP.INIT.

In TDX module spec, section 22.2.35 (TDH.SYS.LP.INIT Leaf), mentions
some environment requirements. I don't see you checking here for it?
Is this already met?



-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer