Re: [libvirt][PATCH RESEND v10 1/5] qemu: provide support to query the SGX capability
On 2/23/22 04:41, Huang, Haibin wrote:
I accept all comments. But I didn't your point for this comment
.
>> +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");
>
> ... which is in contradiction with the way we format it.
[Haibin] sorry, I don't get your point, can you give me the details
Does you mean that change virBufferAsprintf(buf, "<flc>%s</flc>\n",
sgx->flc ? "yes" : "no"); to virBufferAsprintf(buf,
"<flc>%u</flc>\n", sgx->flc);
No. You can keep this particual virBufferAsprintf() as is. What I have
problem with is the parsing side. So if this virQEMUCapsFormatSGXInfo()
function is called, if produces the following XML:
<sgx>
<flc>no</flc>
<epc_size>1024</epc_size>
</sgx>
(I've made the values up)
This corresponds to: sgx->flc = false; sgx->epc_size = 1024;
But when the XML is parsed, in virQEMUCapsParseSGXInfo(), it would se
the following values:
sgx->flc = true; sgx->epc_size = 2014;
Notice the change in ->flc? This is because
virXPathBoolean("boolean(./sgx/flc)") does not evaluate the value of
<flc/> element, but only whether the xpath exists. Therefore, even if
flc's element value is "no", it does exist and as such is evaluated to
true.
Hope this cleans things up.
Michal