[libvirt] [PATCH v8 05/11] qemu: Add support to get the SEV info

[Brijesh Singh]

On 06/07/2018 11:37 AM, Erik Skultety wrote:
> more verbose commit subject:
> qemu: Implement the driver backend for virNodeGetSEVInfo
> 
> On Wed, Jun 06, 2018 at 12:50:11PM -0500, Brijesh Singh wrote:
>> Signed-off-by: Brijesh Singh <<brijesh.singh at amd.com>>
>> ---
>>   src/qemu/qemu_capabilities.c |  7 ++++
>>   src/qemu/qemu_capabilities.h |  4 ++
>>   src/qemu/qemu_driver.c       | 91 ++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 102 insertions(+)
>>
> 
> ...
> 
>>
>> +static int
>> +qemuGetSEVInfo(virQEMUCapsPtr qemuCaps,
> 
> qemuGetSEVInfoToParams would IMHO be a better (iow less confusing) name.


Agreed, its much better name.


> 
>> +               virTypedParameterPtr *params,
>> +               int *nparams,
>> +               unsigned int flags)
>> +{
>> +    int maxpar = 0;
>> +    virSEVCapabilityPtr sev = virQEMUCapsGetSEVCapabilities(qemuCaps);
>> +
>> +    virCheckFlags(VIR_TYPED_PARAM_STRING_OKAY, -1);
>> +
>> +    if (virTypedParamsAddString(params, nparams, &maxpar,
>> +                    VIR_NODE_SEV_PDH, sev->pdh) < 0)
>> +        return -1;
>> +
>> +    if (virTypedParamsAddString(params, nparams, &maxpar,
>> +                    VIR_NODE_SEV_CERT_CHAIN, sev->pdh) < 0)
>> +        goto cleanup;
>> +
>> +    if (virTypedParamsAddUInt(params, nparams, &maxpar,
>> +                    VIR_NODE_SEV_CBITPOS, sev->cbitpos) < 0)
>> +        goto cleanup;
>> +
>> +    if (virTypedParamsAddUInt(params, nparams, &maxpar,
>> +                    VIR_NODE_SEV_REDUCED_PHYS_BITS,
>> +                    sev->reduced_phys_bits) < 0)
>> +        goto cleanup;
>> +
>> +    return 0;
>> +
>> + cleanup:
>> +    return -1;
> 
> So ^this cleanup label is pretty much unnecessary. In order to avoid weird
> errors, we usually create a local copy of the caller-provided argument - in this
> case params - work on it the whole time and only once it's safe, we do a
> VIR_STEAL_PTR to the original pointer, so we should do that here as well.
> 


OK, will do so.


>> +}
>> +
>> +
>> +static int
>> +qemuNodeGetSEVInfo(virConnectPtr conn,
>> +                   virTypedParameterPtr *params,
>> +                   int *nparams,
>> +                   unsigned int flags)
>> +{
>> +    virQEMUDriverPtr driver = conn->privateData;
>> +    virCapsPtr caps = NULL;
>> +    virQEMUCapsPtr qemucaps = NULL;
>> +    virArch hostarch;
>> +    virCapsDomainDataPtr capsdata;
>> +    int ret = -1;
>> +
>> +    if (virNodeGetSevInfoEnsureACL(conn) < 0)
>> +        return ret;
>> +
>> +    if (!(caps = virQEMUDriverGetCapabilities(driver, true)))
>> +        return ret;
>> +
>> +    hostarch = virArchFromHost();
>> +    if (!(capsdata = virCapabilitiesDomainDataLookup(caps,
>> +            VIR_DOMAIN_OSTYPE_HVM, hostarch, VIR_DOMAIN_VIRT_QEMU,
>> +            NULL, NULL))) {
>> +        virReportError(VIR_ERR_INTERNAL_ERROR,
>> +                       _("Cannot find suitable emulator for %s"),
>> +                       virArchToString(hostarch));
>> +        goto UnrefCaps;
>> +    }
> 
> If you use virQEMUCapsCacheLookupByArch below instead, we could drop ^this hunk
> above, am I right?
> 


Ah, I was looking through code to find out suitable APIs for this. 
thanks for suggestion, it seems like it will work for us in this case.



>> +
>> +    qemucaps = virQEMUCapsCacheLookup(driver->qemuCapsCache,
>> +                                      capsdata->emulator);
>> +    VIR_FREE(capsdata);
> 
> ^this could be dropped...
> 

If we use virQEMUCapsCacheLookupByArch() then we could drop this.


>> +    if (!qemucaps)
>> +        goto UnrefCaps;
>> +
>> +    if (!virQEMUCapsGet(qemucaps, QEMU_CAPS_SEV_GUEST)) {
>> +        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
>> +                       _("QEMU does not support SEV guest"));
>> +        goto UnrefQemuCaps;
>> +    }
>> +
>> +    if (qemuGetSEVInfo(qemucaps, params, nparams, flags) < 0)
>> +        goto UnrefQemuCaps;
>> +
>> +    ret = 0;
>> +
>> + UnrefQemuCaps:
> 
> s/UnrefQemuCaps/cleanup
> 
>> +    virObjectUnref(qemucaps);
>> + UnrefCaps:
>> +    virObjectUnref(caps);
> 
> ..^this one too...
> 
> Erik
>