Re: [libvirt] [PATCH 1/5] lib: Add API for specific vCPU hot(un)plug

On Wed, Feb 22, 2017 at 12:16:51 +0000, Daniel Berrange wrote: > On Fri, Feb 10, 2017 at 06:10:18PM +0100, Peter Krempa wrote: > > Similarly to domainSetGuestVcpus this commit adds API which allows to > > modify state of individual vcpus rather than just setting the count. > > > > This allows to enable CPUs in specific guest NUMA nodes to achieve any > > necessary configuration. > > --- > > include/libvirt/libvirt-domain.h | 5 +++++ > > src/driver-hypervisor.h | 7 ++++++ > > src/libvirt-domain.c | 48 ++++++++++++++++++++++++++++++++++++++++ > > src/libvirt_public.syms | 5 +++++ > > src/remote/remote_driver.c | 1 + > > src/remote/remote_protocol.x | 16 +++++++++++++- > > src/remote_protocol-structs | 7 ++++++ > > 7 files changed, 88 insertions(+), 1 deletion(-) > > > > diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h > > index e303140a2..c0f715d66 100644 > > --- a/include/libvirt/libvirt-domain.h > > +++ b/include/libvirt/libvirt-domain.h > > @@ -4528,4 +4528,9 @@ int virDomainSetGuestVcpus(virDomainPtr domain, > > int state, > > unsigned int flags); > > > > +int virDomainSetVcpu(virDomainPtr domain, > > + const char *vcpumap, > > + int state, > > + unsigned int flags); > > In adding support for this to perl/go bindings I see that this is using > a different style to the existing APIs. With the exception of the > virDomainSetGuestVcpus() API, everything else dealing with CPU maps > uses an 'unsigned char *cpu' & 'int maplen' pair to store the data as > a bitmap. I think we should change this API to also use the bitmap > rather than the textual format as it gives consistency with other > APIs, particularly when mapping into other languages. For example > in Go, the bitmaps get turned into a boolean array, so it is a very > natural representation to manipulate - the textual format is rather > inconvenient in this respect. I modelled this API after the qemuDomainSetGuestVcpus and qemuDomainGetGuestVcpusParams which already uses the string representation rather the harder-to-use bitmap one, since they are in for a while we can't change those.