Re: [PATCH 07/10] x86/tdx: Extend TDX_MODULE_CALL to support more TDCALL/SEAMCALL leafs

[Peter Zijlstra]

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.