[libvirt][PATCH v13 2/6] Get SGX capabilities form QMP

[Michal Prívozník]

On 7/1/22 21:14, Lin Yang wrote:
> From: Haibin Huang <haibin.huang at intel.com>
> 
> Generate the QMP command for query-sgx-capabilities and the command
> return sgx capabilities from QMP.
> 
> {"execute":"query-sgx-capabilities"}
> 
> the right reply:
>   {"return":
>     {
>       "sgx": true,
>       "section-size": 197132288,
>       "flc": true
>     }
>   }
> 
> the error reply:
>   {"error":
>     {"class": "GenericError", "desc": "SGX is not enabled in KVM"}
>   }
> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> Signed-off-by: Haibin Huang <haibin.huang at intel.com>
> ---
>  src/qemu/qemu_monitor.c      |  10 ++++
>  src/qemu/qemu_monitor.h      |   3 +
>  src/qemu/qemu_monitor_json.c | 113 +++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor_json.h |   4 ++
>  4 files changed, 130 insertions(+)
> 
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index fda5d2f368..a1b2138921 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -3653,6 +3653,16 @@ qemuMonitorGetSEVCapabilities(qemuMonitor *mon,
>  }
>  
>  
> +int
> +qemuMonitorGetSGXCapabilities(qemuMonitor *mon,
> +                              virSGXCapability **capabilities)
> +{
> +    QEMU_CHECK_MONITOR(mon);
> +
> +    return qemuMonitorJSONGetSGXCapabilities(mon, capabilities);
> +}
> +
> +
>  int
>  qemuMonitorNBDServerStart(qemuMonitor *mon,
>                            const virStorageNetHostDef *server,
> diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
> index 95267ec6c7..451ac8eec9 100644
> --- a/src/qemu/qemu_monitor.h
> +++ b/src/qemu/qemu_monitor.h
> @@ -864,6 +864,9 @@ int qemuMonitorGetGICCapabilities(qemuMonitor *mon,
>  int qemuMonitorGetSEVCapabilities(qemuMonitor *mon,
>                                    virSEVCapability **capabilities);
>  
> +int qemuMonitorGetSGXCapabilities(qemuMonitor *mon,
> +                                  virSGXCapability **capabilities);
> +
>  typedef enum {
>    QEMU_MONITOR_MIGRATE_BACKGROUND       = 1 << 0,
>    QEMU_MONITOR_MIGRATE_NON_SHARED_DISK  = 1 << 1, /* migration with non-shared storage with full disk copy */
> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
> index 3aad2ab212..c900956f82 100644
> --- a/src/qemu/qemu_monitor_json.c
> +++ b/src/qemu/qemu_monitor_json.c
> @@ -6445,6 +6445,119 @@ qemuMonitorJSONGetSEVCapabilities(qemuMonitor *mon,
>      return 1;
>  }
>  
> +
> +/**
> + * qemuMonitorJSONGetSGXCapabilities:
> + * @mon: qemu monitor object
> + * @capabilities: pointer to pointer to a SGX capability structure to be filled
> + *
> + * This function queries and fills in INTEL's SGX platform-specific data.
> + * Note that from QEMU's POV both -object sgx-epc and query-sgx-capabilities
> + * can be present even if SGX is not available, which basically leaves us with
> + * checking for JSON "GenericError" in order to differentiate between compiled-in
> + * support and actual SGX support on the platform.
> + *
> + * Returns: -1 on error,
> + *           0 if SGX is not supported, and
> + *           1 if SGX is supported on the platform.
> + */
> +int
> +qemuMonitorJSONGetSGXCapabilities(qemuMonitor *mon,
> +                                  virSGXCapability **capabilities)
> +{
> +    g_autoptr(virJSONValue) cmd = NULL;
> +    g_autoptr(virJSONValue) reply = NULL;
> +    g_autoptr(virSGXCapability) capability = NULL;
> +
> +    virJSONValue *sections = NULL;
> +    virJSONValue *caps;
> +    bool flc = false;
> +    bool sgx1 = false;
> +    bool sgx2 = false;
> +    unsigned long long section_size = 0;
> +    unsigned long long size;
> +    size_t i;
> +
> +    *capabilities = NULL;
> +    capability = g_new0(virSGXCapability, 1);
> +
> +    if (!(cmd = qemuMonitorJSONMakeCommand("query-sgx-capabilities", NULL)))
> +        return -1;
> +
> +    if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
> +        return -1;
> +
> +    /* QEMU has only compiled-in support of SGX */
> +    if (qemuMonitorJSONHasError(reply, "GenericError"))
> +        return 0;
> +
> +    if (qemuMonitorJSONCheckError(cmd, reply) < 0)
> +        return -1;
> +
> +    caps = virJSONValueObjectGetObject(reply, "return");
> +
> +    if (virJSONValueObjectGetBoolean(caps, "flc", &flc) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-sgx-capabilities reply was missing 'flc' field"));
> +        return -1;
> +    }
> +    capability->flc = flc;
> +
> +    if (virJSONValueObjectGetBoolean(caps, "sgx1", &sgx1) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-sgx-capabilities reply was missing 'sgx1' field"));
> +        return -1;
> +    }
> +    capability->sgx1 = sgx1;
> +
> +    if (virJSONValueObjectGetBoolean(caps, "sgx2", &sgx2) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-sgx-capabilities reply was missing 'sgx2' field"));
> +        return -1;
> +    }
> +    capability->sgx2 = sgx2;
> +
> +    if (virJSONValueObjectGetNumberUlong(caps, "section-size", &section_size) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-sgx-capabilities reply was missing 'section-size' field"));
> +        return -1;
> +    }
> +    capability->section_size = section_size/1024;

Spaces around the operand please.

> +
> +    if (!(sections = virJSONValueObjectGetArray(caps, "sections"))) {
> +        capability->nSections = 0;
> +        capability->pSections = NULL;

This is needless. g_new0() used above made sure that the memory is
zeroed out upon allocation, so these two lines are NOP.

> +        VIR_INFO("Sections was not obtained, so QEMU version is 6.2.0");

VIR_INFO() is probably too harsh. It's not anything that users should be
concerned about. VIR_DEBUG() is much better. But then again, when debug
logs are enabled then the QMP command and its reply are seen in the log
and thus anybody reading it sees immediately whether a part is missing
or not.

> +        *capabilities = g_steal_pointer(&capability);
> +        return 1;
> +    }
> +
> +    // Got the section, the QEMU version is above 7.0.0
> +    capability->nSections = virJSONValueArraySize(sections);
> +    capability->pSections = g_new0(virSection, capability->nSections + 1);

This + 1 looks wrong to me. We already have nSections, and pSections is
not an array of pointers either. So NULL terminated array is a bit overkill.

> +
> +    for (i = 0; i < capability->nSections; i++) {
> +        virJSONValue *elem = virJSONValueArrayGet(sections, i);
> +
> +        if (virJSONValueObjectGetNumberUlong(elem, "size", &size) < 0) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                           _("query-sgx-capabilities reply was missing 'size' field"));
> +            return -1;
> +        }
> +        capability->pSections[i].size = size/1024;
> +
> +        if (virJSONValueObjectGetNumberUint(elem, "node", &(capability->pSections[i].node)) < 0) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                           _("query-sgx-capabilities reply was missing 'node' field"));
> +            return -1;
> +        }
> +    }
> +
> +    *capabilities = g_steal_pointer(&capability);
> +    return 1;
> +}

Michal