Re: RFC: sgx-epc is not listed in machine type help

[Yang Zhong]

On Thu, Apr 28, 2022 at 02:18:54PM +0200, Jinpu Wang wrote:
> On Thu, Apr 28, 2022 at 2:05 PM Yang Zhong <yang.zhong@intel.com> wrote:
> >
> > On Thu, Apr 28, 2022 at 01:59:33PM +0200, Jinpu Wang wrote:
> > > Hi Yang, hi Paolo,
> > >
> > > We noticed sgx-epc machine type is not listed in the output of
> > > "qemu-system-x86_64 -M ?",
> snip
> > >
> > >
> > > I think this would cause confusion to users, is there a reason behind 
> > > this?
> > >
> >
> >   No specific machine type for SGX, and SGX is only supported in Qemu PC 
> > and Q35 platform.
> Hi Yang,
> 
> Thanks for your quick reply. Sorry for the stupid question.
> The information I've got from intel or the help sample from
> https://www.qemu.org/docs/master/system/i386/sgx.html, We need to
> specify commands something like this to run SGX-EPC guest:
> qemu-system-x86-64 -m 2G -nographic -enable-kvm -cpu
> host,+sgx-provisionkey  -object
> memory-backend-epc,id=mem1,size=512M,prealloc=on -M
> sgx-epc.0.memdev=mem1,sgx-epc.0.node=0 /tmp/volume-name.img
> 
> Do you mean internally QEMU is converting -M sgx-epc to PC or Q35, can
> I choose which one to use?
>

  Qemu will replace object with compound key, in that time, Paolo asked me
  to use "-M sgx-epc..." to replace "-object sgx-epc..." from Qemu command line.
  
  So the "-M sgx-epc..." will get sgx-epc's parameters from hash key, and
  do not covert sgx-epc to PC or Q35.

  SGX is only one Intel cpu feature, and no dedicated SGX Qemu machine type for 
SGX. 
  
  Another compound key example:
  "-M pc,smp.cpus=4,smp.cores=1,smp.threads=1"
 
  Yang

 
> Thanks!
> Jinpu