[libvirt] [PATCH 2/8] qemuBuildVsockDevStr: allow passing a fdprefix

[John Ferlan]

$subj:

qemu: Add prefix for vsock vhostfd

On 05/30/2018 10:57 AM, Ján Tomko wrote:
> A string prefix for the file descriptor name. Domain startup

consider:

Alter qemuBuildVsockDevStr to allow passing a prefix for the vhostfd
file descriptor name.

> uses the numeric value of fd without a prefix, but hotplug
> will need to use a prefix because file descriptor names
> passed via add-fd cannot start with a number.

This doesn't use add-fd, it uses qemuMonitorAddDeviceWithFd - similar
reasoning, just different command.

As an aside, qemuMonitorAddDeviceWithFd has a NULLSTR(fdname), but
passes fdname to qemuMonitorSendFileHandle which just assumes it's there
as does qemuMonitorJSONSendFileHandle ("s:fdname", fdname).

> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1291851
> 
> Signed-off-by: Ján Tomko <jtomko at redhat.com>
> ---
>  src/qemu/qemu_command.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 

Slightly different algorithm than VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO
and SCSIVHost) but who's to say the other 2 are more correct (at least
w/r/t passing the "%d" or "vsockfd%d" string to qemuBuildVsockDevStr
instead of building it in the method). Your call on how to handle.

w/ commit message cleanup...

Reviewed-by: John Ferlan <jferlan at redhat.com>

John