[libvirt] [PATCH 08/22] Introduce virConnectCompareHypervisorCPU public API

[Collin Walling]

On 05/16/2018 04:39 AM, Jiri Denemark wrote:
> This new API compares the given CPU description with the CPU the
> specified hypervisor is able to provide on the host. It is a more useful
> version of virConnectCompareCPU, which compares the CPU definition with
> the host CPU without considering any specific hypervisor and its
> abilities.
> 
> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
> ---
>  include/libvirt/libvirt-host.h |  7 ++++
>  src/driver-hypervisor.h        | 10 +++++
>  src/libvirt-host.c             | 72 +++++++++++++++++++++++++++++++++-
>  src/libvirt_public.syms        |  5 +++
>  4 files changed, 93 insertions(+), 1 deletion(-)
> 
> diff --git a/include/libvirt/libvirt-host.h b/include/libvirt/libvirt-host.h
> index 07b5d15943..e2054baebc 100644
> --- a/include/libvirt/libvirt-host.h
> +++ b/include/libvirt/libvirt-host.h
> @@ -640,6 +640,13 @@ typedef enum {
>  int virConnectCompareCPU(virConnectPtr conn,
>                           const char *xmlDesc,
>                           unsigned int flags);
> +int virConnectCompareHypervisorCPU(virConnectPtr conn,
> +                                   const char *emulator,
> +                                   const char *arch,
> +                                   const char *machine,
> +                                   const char *virttype,
> +                                   const char *xmlCPU,
> +                                   unsigned int flags);
>  
>  int virConnectGetCPUModelNames(virConnectPtr conn,
>                                 const char *arch,
> diff --git a/src/driver-hypervisor.h b/src/driver-hypervisor.h
> index e71a72a441..d64de2d54c 100644
> --- a/src/driver-hypervisor.h
> +++ b/src/driver-hypervisor.h
> @@ -673,6 +673,15 @@ typedef int
>                             const char *cpu,
>                             unsigned int flags);
>  
> +typedef int
> +(*virDrvConnectCompareHypervisorCPU)(virConnectPtr conn,
> +                                     const char *emulator,
> +                                     const char *arch,
> +                                     const char *machine,
> +                                     const char *virttype,
> +                                     const char *xmlCPU,
> +                                     unsigned int flags);
> +
>  typedef char *
>  (*virDrvConnectBaselineCPU)(virConnectPtr conn,
>                              const char **xmlCPUs,
> @@ -1532,6 +1541,7 @@ struct _virHypervisorDriver {
>      virDrvDomainSetVcpu domainSetVcpu;
>      virDrvDomainSetBlockThreshold domainSetBlockThreshold;
>      virDrvDomainSetLifecycleAction domainSetLifecycleAction;
> +    virDrvConnectCompareHypervisorCPU connectCompareHypervisorCPU;
>  };
>  
>  
> diff --git a/src/libvirt-host.c b/src/libvirt-host.c
> index ed689b9ec2..17cf183499 100644
> --- a/src/libvirt-host.c
> +++ b/src/libvirt-host.c
> @@ -954,7 +954,11 @@ virConnectIsSecure(virConnectPtr conn)
>   * @xmlDesc: XML describing the CPU to compare with host CPU
>   * @flags: bitwise-OR of virConnectCompareCPUFlags
>   *
> - * Compares the given CPU description with the host CPU
> + * Compares the given CPU description with the host CPU.
> + *
> + * See vitConnectCompareHypervisorCPU() if you want to consider hypervisor
> + * abilities and compare the CPU to the CPU which a hypervisor is able to
> + * provide on the host.
>   *
>   * Returns comparison result according to enum virCPUCompareResult. If
>   * VIR_CONNECT_COMPARE_CPU_FAIL_INCOMPATIBLE is used and @xmlDesc CPU is
> @@ -992,6 +996,72 @@ virConnectCompareCPU(virConnectPtr conn,
>  }
>  
>  
> +/**
> + * virConnectCompareHypervisorCPU:
> + * @conn: pointer to the hypervisor connection
> + * @emulator: path to the emulator binary
> + * @arch: domain architecture
> + * @machine: machine type
> + * @virttype: virtualization type
> + * @xmlCPU: XML describing the CPU to be compared
> + * @flags: bitwise-OR of virConnectCompareCPUFlags
> + *
> + * Compares the given CPU description with the CPU the specified hypervisor is
> + * able to provide on the host. Any of @emulator, @arch, @machine, and
> + * @virttype parameters may be NULL; libvirt will choose sensible defaults
> + * tailored to the host and its current configuration.
> + *
> + * This is different from virConnectCompareCPU() which compares the CPU
> + * definition with the host CPU without considering any specific hypervisor and
> + * its abilities.
> + *
> + * Returns comparison result according to enum virCPUCompareResult. If
> + * VIR_CONNECT_COMPARE_CPU_FAIL_INCOMPATIBLE is used and @xmlCPU is
> + * incompatible with the CPU the specified hypervisor is able to provide on the
> + * host, this function will return VIR_CPU_COMPARE_ERROR (instead of
> + * VIR_CPU_COMPARE_INCOMPATIBLE) and the error will use the
> + * VIR_ERR_CPU_INCOMPATIBLE code with a message providing more details about
> + * the incompatibility.
> + */
> +int
> +virConnectCompareHypervisorCPU(virConnectPtr conn,
> +                               const char *emulator,
> +                               const char *arch,
> +                               const char *machine,
> +                               const char *virttype,
> +                               const char *xmlCPU,
> +                               unsigned int flags)
> +{
> +    VIR_DEBUG("conn=%p, emulator=%s, arch=%s, machine=%s, "
> +              "virttype=%s, xmlCPU=%s, flags=0x%x",
> +              conn, NULLSTR(emulator), NULLSTR(arch), NULLSTR(machine),
> +              NULLSTR(virttype), NULLSTR(xmlCPU), flags);
> +
> +    virResetLastError();
> +
> +    virCheckConnectReturn(conn, VIR_CPU_COMPARE_ERROR);
> +    virCheckNonNullArgGoto(xmlCPU, error);
> +
> +    if (conn->driver->connectCompareHypervisorCPU) {
> +        int ret;
> +
> +        ret = conn->driver->connectCompareHypervisorCPU(conn, emulator, arch,
> +                                                        machine, virttype,
> +                                                        xmlCPU, flags);
> +        if (ret == VIR_CPU_COMPARE_ERROR)
> +            goto error;

Admittedly I did not look too closely, but will the compareHypervisorCPU functions actually
return "VIR_CPU_COMPARE_ERROR" on error? If so, wouldn't it be more sensible to return a 
"VIR_HYPERVISOR_CPU_COMPARE_ERROR" instead?

> +
> +        return ret;
> +    }
> +
> +    virReportUnsupportedError();
> +
> + error:
> +    virDispatchError(conn);
> +    return VIR_CPU_COMPARE_ERROR;
> +}
> +
> +
>  /**
>   * virConnectGetCPUModelNames:
>   *
> diff --git a/src/libvirt_public.syms b/src/libvirt_public.syms
> index 95df3a0dbc..97597d7708 100644
> --- a/src/libvirt_public.syms
> +++ b/src/libvirt_public.syms
> @@ -785,4 +785,9 @@ LIBVIRT_4.1.0 {
>          virStoragePoolLookupByTargetPath;
>  } LIBVIRT_3.9.0;
>  
> +LIBVIRT_4.4.0 {
> +    global:
> +        virConnectCompareHypervisorCPU;
> +} LIBVIRT_4.1.0;
> +
>  # .... define new API here using predicted next version number ....
> 


-- 
Respectfully,
- Collin Walling