Re: [PATCH v4 4/4] hw/i386/sgx: Attach SGX-EPC objects to machine

[Yang Zhong]

On Mon, Feb 07, 2022 at 09:37:52AM +0100, Igor Mammedov wrote:
> On Sat,  5 Feb 2022 13:45:26 +0100
> Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> 
> > Previously SGX-EPC objects were exposed in the QOM tree at a path
> > 
> >   /machine/unattached/device[nn]
> > 
> > where the 'nn' varies depending on what devices were already created.
> > 
> > With this change the SGX-EPC objects are now at
> > 
> >   /machine/sgx-epc[nn]
> > 
> > where the 'nn' of the first SGX-EPC object is always zero.
> 
> yet again, why it's necessary?


  Igor, Sorry for delay feedback because of Chinese New Year holiday.

  This series patches are to fix below issues I reported before,
  https://lists.nongnu.org/archive/html/qemu-devel/2021-11/msg05670.html

  Since the /machine/unattached/device[0] is used by vcpu and Libvirt
  use this interface to get unavailable-features list. But in the SGX
  VM, the device[0] will be occupied by virtual sgx epc device, Libvirt
  can't get unavailable-features from this device[0].

  Although patch 2 in this series already fixed "unavailable-features" issue,
  this patch can move sgx virtual device from /machine/unattached/device[nn]
  to /machine/sgx-epc[nn], which seems more clear. Thanks!

  Yang
  

> 
> > 
> > Reported-by: Yang Zhong <yang.zhong@intel.com>
> > Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> > Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> > ---
> >  hw/i386/sgx.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/hw/i386/sgx.c b/hw/i386/sgx.c
> > index a2b318dd938..3ab2217ca43 100644
> > --- a/hw/i386/sgx.c
> > +++ b/hw/i386/sgx.c
> > @@ -304,6 +304,8 @@ void pc_machine_init_sgx_epc(PCMachineState *pcms)
> >      for (list = x86ms->sgx_epc_list; list; list = list->next) {
> >          obj = object_new("sgx-epc");
> >  
> > +        object_property_add_child(OBJECT(pcms), "sgx-epc[*]", OBJECT(obj));
> > +
> >          /* set the memdev link with memory backend */
> >          object_property_parse(obj, SGX_EPC_MEMDEV_PROP, 
> > list->value->memdev,
> >                                &error_fatal);