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Message-ID: <20230713103946.GG3139243@hirez.programming.kicks-ass.net>
Date: Thu, 13 Jul 2023 12:39:46 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: "Huang, Kai" <kai.huang@...el.com>
Cc: "Hansen, Dave" <dave.hansen@...el.com>,
"Christopherson,, Sean" <seanjc@...gle.com>,
"bp@...en8.de" <bp@...en8.de>, "x86@...nel.org" <x86@...nel.org>,
"hpa@...or.com" <hpa@...or.com>,
"mingo@...hat.com" <mingo@...hat.com>,
"kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
"tglx@...utronix.de" <tglx@...utronix.de>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"pbonzini@...hat.com" <pbonzini@...hat.com>,
"Yamahata, Isaku" <isaku.yamahata@...el.com>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"sathyanarayanan.kuppuswamy@...ux.intel.com"
<sathyanarayanan.kuppuswamy@...ux.intel.com>
Subject: Re: [PATCH 07/10] x86/tdx: Extend TDX_MODULE_CALL to support more
TDCALL/SEAMCALL leafs
On Thu, Jul 13, 2023 at 10:24:48AM +0000, Huang, Kai wrote:
> On Thu, 2023-07-13 at 10:19 +0000, Huang, Kai wrote:
> > On Thu, 2023-07-13 at 10:43 +0200, Peter Zijlstra wrote:
> > > On Thu, Jul 13, 2023 at 08:02:54AM +0000, Huang, Kai wrote:
> > >
> > > > Sorry I am ignorant here. Won't "clearing ECX only" leave high bits of
> > > > registers still containing guest's value?
> > >
> > > architecture zero-extends 32bit stores
> >
> > Sorry, where can I find this information? Looking at SDM I couldn't find :-(
> >
> >
>
> Hmm.. I think I found it -- it's in SDM vol 1:
>
> 3.4.1.1 General-Purpose Registers in 64-Bit Mode
>
> 32-bit operands generate a 32-bit result, zero-extended to a 64-bit result in
> the destination general-purpose register.
Yes, that's it.
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