[libvirt][PATCH v11 1/4] qemu: provide support to query the SGX capability

[Huang, Haibin]

> -----Original Message-----
> From: Peter Krempa <pkrempa at redhat.com>
> Sent: Thursday, May 12, 2022 12:05 AM
> To: Yang, Lin A <lin.a.yang at intel.com>
> Cc: libvir-list at redhat.com; Huang, Haibin <haibin.huang at intel.com>; Ding,
> Jian-feng <jian-feng.ding at intel.com>; Zhong, Yang <yang.zhong at intel.com>
> Subject: Re: [libvirt][PATCH v11 1/4] qemu: provide support to query the SGX
> capability
> 
> On Tue, May 10, 2022 at 23:11:09 -0700, Lin Yang wrote:
> > From: Haibin Huang <haibin.huang at intel.com>
> >
> > QEMU version >= 6.2.0 provides support for creating enclave on SGX x86
> > platform using Software Guard Extensions (SGX) feature.
> > This patch adds support to query the SGX capability from the qemu.
> >
> > Signed-off-by: Haibin Huang <haibin.huang at intel.com>
> > ---
> >  src/conf/domain_capabilities.c                |  10 ++
> >  src/conf/domain_capabilities.h                |  13 ++
> >  src/libvirt_private.syms                      |   1 +
> >  src/qemu/qemu_capabilities.c                  | 119 ++++++++++++++++++
> >  src/qemu/qemu_capabilities.h                  |   6 +
> >  src/qemu/qemu_capspriv.h                      |   4 +
> >  src/qemu/qemu_monitor.c                       |  10 ++
> >  src/qemu/qemu_monitor.h                       |   3 +
> >  src/qemu/qemu_monitor_json.c                  | 104 +++++++++++++--
> >  src/qemu/qemu_monitor_json.h                  |   9 ++
> >  .../caps_6.2.0.x86_64.replies                 |  22 +++-
> >  .../caps_6.2.0.x86_64.xml                     |   5 +
> >  .../caps_7.0.0.x86_64.replies                 |  22 +++-
> >  .../caps_7.0.0.x86_64.xml                     |   5 +
> >  14 files changed, 318 insertions(+), 15 deletions(-)
> 
> This is not a full review. Couple of points:
> 
> 1) Do not mix other changes with adding QEMU_CAPS* stuff
>     Basically theres waaay too much going on in this patch and it
>     definitely can be separated into smaller chunks. The QEMU_CAPS is
>     just one of them.
>     Separate at least:
>         - qemu monitor command introduction
>         - domain capabilities data structs for sgx
>         - parsing and formatting of the XML
>         - adding of the QEMU_CAPS_ flag
[Haibin] may be "domain capabilities structs" should be put in "qemu monitor command", because the virSGXCapability will be used by qemu monitor command.
> 2) caps for qemu-7.1 were added very recently
>     You'll need to fix that one too since you added an extra query. Make
>     sure that you _don't_ add the faking of SXG into that file, but
>     rather the error case. My box doesn't support SGX so it will be
>     overwritten in my next refresh anyways.
[Haibin] Is this advice just for qemu-7.1 or all qemu version?
This is just for unit test, why not add the faking of SGX into that file. If don't add faking of SGX into that file, the unit can not pass.
> 
> [...]
> 
> > @@ -4706,6 +4805,21 @@ virQEMUCapsFormatSEVInfo(virQEMUCaps
> *qemuCaps,
> > virBuffer *buf)  }
> >
> >
> > +static void
> > +virQEMUCapsFormatSGXInfo(virQEMUCaps *qemuCaps,
> > +                         virBuffer *buf) {
> > +    virSGXCapabilityPtr sgx =
> > +virQEMUCapsGetSGXCapabilities(qemuCaps);
> > +
> > +    virBufferAddLit(buf, "<sgx>\n");
> > +    virBufferAdjustIndent(buf, 2);
> > +    virBufferAsprintf(buf, "<flc>%s</flc>\n", sgx->flc ? "yes" :
> > + "no");
> 
> Don't use the ternary operator ('?'), use a full if/else branch instead or pick a
> better data structure.
> 
> > +    virBufferAsprintf(buf, "<epc_size>%u</epc_size>\n", sgx->epc_size);
> > +    virBufferAdjustIndent(buf, -2);
> > +    virBufferAddLit(buf, "</sgx>\n"); }