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

[Jiri Denemark]

On Tue, May 22, 2018 at 18:27:51 -0400, Collin Walling wrote:
> 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?

The function returns a value from enum virCPUCompareResult just like the
original connectCompareCPU API. I don't see a reason for introducing a
new set of return values for the new connectCompareHypervisorCPU.

Jirka