linux-kernel - Re: [PATCH v12 07/22] x86/virt/tdx: Add skeleton to enable TDX on demand

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Message-ID: <716cdf73799a5322cbe34c7f23d582f8a3ecf301.camel@intel.com>
Date:   Fri, 30 Jun 2023 10:09:08 +0000
From:   "Huang, Kai" <kai.huang@...el.com>
To:     "peterz@...radead.org" <peterz@...radead.org>
CC:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
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Subject: Re: [PATCH v12 07/22] x86/virt/tdx: Add skeleton to enable TDX on
 demand

On Fri, 2023-06-30 at 11:22 +0200, Peter Zijlstra wrote:
> On Thu, Jun 29, 2023 at 12:15:13AM +0000, Huang, Kai wrote:
> 
> > > 	Can be called locally or through an IPI function call.
> > > 
> > 
> > Thanks.  As in another reply, if using spinlock is OK, then I think we can say
> > it will be called either locally or through an IPI function call.  Otherwise, we
> > do via a new separate function tdx_global_init() and no lock is needed in that
> > function.  The caller should call it properly.
> 
> IPI must use raw_spinlock_t. I'm ok with using raw_spinlock_t if there's
> actual need for that, but the code as presented didn't -- in comments or
> otherwise -- make it clear why it was as it was.

There's no hard requirement as I replied in another email.

Presumably you prefer the option to have a dedicated tdx_global_init() so we can
avoid the raw_spinlock_t?

Thanks.

> 
> TDX not specifying time constraints on the various TD/SEAM-CALLs is
> ofcourse sad, but alas.

Agreed.