[libvirt][PATCH v4 2/4] qemu: Add command-line to generate SGX EPC memory backend

[Huang, Haibin]

> -----Original Message-----
> From: Tim Wiederhake <twiederh at redhat.com>
> Sent: Monday, July 5, 2021 7:32 PM
> To: Huang, Haibin <haibin.huang at intel.com>
> Cc: libvir-list at redhat.com; Ding, Jian-feng <jian-feng.ding at intel.com>; Yang,
> Lin A <lin.a.yang at intel.com>; Lu, Lianhao <lianhao.lu at intel.com>
> Subject: Re: [libvirt][PATCH v4 2/4] qemu: Add command-line to generate
> SGX EPC memory backend
> 
> On Thu, 2021-07-01 at 20:10 +0800, Haibin Huang wrote:
> > From: Lin Yang <lin.a.yang at intel.com>
> >
> > According to the result parsing from xml, add the argument of SGX EPC
> > memory backend into QEMU command line:
> >
> >     -object memory-backend-epc,id=mem1,size=<epc_size>K,prealloc \
> >     -sgx-epc id=epc1,memdev=mem1
> > ---
> >  src/qemu/qemu_command.c | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >
> > diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index
> > 01812cd39b..2c3785886c 100644
> > --- a/src/qemu/qemu_command.c
> > +++ b/src/qemu/qemu_command.c
> > @@ -9869,6 +9869,27 @@ qemuBuildVsockCommandLine(virCommandPtr
> cmd,
> >  }
> >
> >
> > +static int
> > +qemuBuildSGXCommandLine(virCommandPtr cmd, virDomainSGXDefPtr
> sgx) {
> > +    g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
> > +
> > +    if (!sgx)
> > +        return 0;
> > +
> > +    VIR_DEBUG("sgx->epc_size=%lluKiB", sgx->epc_size);
> > +
> > +    virBufferAsprintf(&buf, "memory-backend-
> > epc,id=mem1,size=%lluK,prealloc", sgx->epc_size);
> > +    virCommandAddArg(cmd, "-object");
> > +    virCommandAddArgBuffer(cmd, &buf);
> 
> virCommandAddArgFormat?
[Haibin] ok, I will change to virCommandAddArgFormat
> 
> > +
> > +    virCommandAddArg(cmd, "-sgx-epc");
> > +    virCommandAddArg(cmd, "id=epc1,memdev=mem1");
> > +
> > +    return 0;
> > +}
> > +
> > +
> >  /*
> >   * Constructs a argv suitable for launching qemu with config defined
> >   * for a given virtual machine.
> > @@ -10154,6 +10175,9 @@ qemuBuildCommandLine(virQEMUDriverPtr
> driver,
> >          cfg->logTimestamp)
> >          virCommandAddArgList(cmd, "-msg", "timestamp=on", NULL);
> >
> > +    if (qemuBuildSGXCommandLine(cmd, def->sgx) < 0)
> > +        return NULL;
> > +
> 
> Personal opinion: I would not add this to the end of the function, but place it
> next to the call to "qemuBuildSEVCommandLine(...)". Or replace the call to
> qemuBuildSEVCommandLine() with a "qemuBuildSecurityCommandLine()",
> which in turn calls qemuBuild{SEV,SGX}CommandLine().
[Haibin] ok, good point.
> 
> Regards,
> Tim
> 
> >      return g_steal_pointer(&cmd);
> >  }
> >
>