[pve-devel] [PATCH] enable drive-mirror with iothread for qemu 2.7

[Wolfgang Bumiller]

On Mon, Oct 17, 2016 at 11:33:44AM +0200, Alexandre DERUMIER wrote:
> >>But we actually have 3 states here: kvm binary version (not interesting
> >>when hotpluggin), machine version (only interesting when migrating),
> >>running qemu version (probably the most important).
> 
> >>The machine part (query-machines) would give us the qemu version the
> >>VM was originally started with before migrations happened, but do all 3
> >>patches/series depend on this version (ie. the pc-i440fx machine
> >>version), or the actually running qemu? I'm pretty sure iothread issues
> >>are gone with an updated qemu regardless of the machine or what qemu we
> >>currently have in /bin if it's not the running one (kvm_user_version()).
> >>The latter is only ever interesting when starting a new VM as far as I
> >>can tell, whereas for hotplugging and migration the machine and
> >>running-version matter. (The latter probably much more than the former).
> 
> yes, I thinked about that too this weekend.
> 
> for iothread, I think query-machines will do the job. 
> We don't care about machine version, only the running qemu binary version is needed.

But wouldn't that be query-version? If we migrate from 2.6 to 2.7 then
query-machine would give us pc-i440fx-2.6, no?

> 
> 
> For cpu hotplug, only machine version is needed.(I think I can remove the extra kvm_version() call)
> 
> 
> I'll update my patches
> 
> 
> 
> ----- Mail original -----
> De: "Wolfgang Bumiller" <w.bumiller at proxmox.com>
> À: "aderumier" <aderumier at odiso.com>
> Cc: "pve-devel" <pve-devel at pve.proxmox.com>
> Envoyé: Lundi 17 Octobre 2016 11:21:10
> Objet: Re: [pve-devel] [PATCH] enable drive-mirror with iothread for qemu 2.7
> 
> On Mon, Oct 17, 2016 at 10:47:56AM +0200, Wolfgang Bumiller wrote: 
> > On Thu, Oct 13, 2016 at 12:00:42PM +0200, Alexandre Derumier wrote: 
> > > Signed-off-by: Alexandre Derumier <aderumier at odiso.com> 
> > > --- 
> > > PVE/QemuServer.pm | 7 +++++-- 
> > > 1 file changed, 5 insertions(+), 2 deletions(-) 
> > > 
> > > diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm 
> > > index 05edd7a..ec8df94 100644 
> > > --- a/PVE/QemuServer.pm 
> > > +++ b/PVE/QemuServer.pm 
> > > @@ -5933,8 +5933,11 @@ sub clone_disk { 
> > > if (!$running || $snapname) { 
> > > qemu_img_convert($drive->{file}, $newvolid, $size, $snapname, $sparseinit); 
> > > } else { 
> > > - #qemu 2.6 
> > > - die "drive-mirror is not working currently when iothread is enabled" if $drive->{iothread}; 
> > > + 
> > > + my $kvmver = kvm_user_version(); 
> > > + if (!qemu_machine_feature_enabled (undef, $kvmver, 2, 7)) { 
> > 
> > Considering this is in the path where $running is true, I think this 
> > should include the get_current_qemu_machine() parameter? 
> 
> Actually, the same for the cpu hotplug and virtio-scsi iothread patches. 
> In the cpuhotplug v1 series you said: 
> > qemu_machine_feature_enabled() return current qemu process or if machine version is forced (live migration for example), 
> > it's return the machine version. 
> 
> But we actually have 3 states here: kvm binary version (not interesting 
> when hotpluggin), machine version (only interesting when migrating), 
> running qemu version (probably the most important). 
> 
> The machine part (query-machines) would give us the qemu version the 
> VM was originally started with before migrations happened, but do all 3 
> patches/series depend on this version (ie. the pc-i440fx machine 
> version), or the actually running qemu? I'm pretty sure iothread issues 
> are gone with an updated qemu regardless of the machine or what qemu we 
> currently have in /bin if it's not the running one (kvm_user_version()). 
> The latter is only ever interesting when starting a new VM as far as I 
> can tell, whereas for hotplugging and migration the machine and 
> running-version matter. (The latter probably much more than the former). 
> 
>