[RFC] qemu: Check for changes in qemu modules directory
Daniel P. Berrangé
berrange at redhat.com
Tue Aug 25 17:41:59 UTC 2020
On Tue, Aug 25, 2020 at 11:23:13AM -0600, Jim Fehlig wrote:
> Hi All,
>
> Any comments on this RFC patch? Is this something we would like to see in
> the 6.7.0 release?
Not done a full review yet, but it looks reasonable as an approach and
the code isn't too complex.
>
> On 8/20/20 5:03 PM, Jim Fehlig wrote:
> > Add a configuration option for specifying location of the qemu modules
> > directory, defaulting to /usr/lib64/qemu. Then use this location to
> > check for changes in the directory, indicating that a qemu module has
> > changed and capabilities need to be reprobed.
> >
> > Signed-off-by: Jim Fehlig <jfehlig at suse.com>
> > ---
> >
> > This is a mildly tested impl of the idea discussed here (and elsewhere
> > in the thread)
> >
> > https://www.redhat.com/archives/libvir-list/2020-August/msg00684.html
> >
> > I've checked that both system and session caches are updated when a
> > qemu modules package is updated. I'll do some more testing but wanted
> > to send the patch for early comments. Testing in other environments
> > would be much appreciated. Thanks!
>
> I've tried some more configurations and haven't noticed any problems with
> the patch thus far. The request for additional eyeballs and testing still
> valid though :-).
>
> Regards,
> Jim
>
> >
> > meson.build | 6 ++++++
> > meson_options.txt | 1 +
> > src/qemu/qemu_capabilities.c | 35 +++++++++++++++++++++++++++++++++++
> > 3 files changed, 42 insertions(+)
> >
> > diff --git a/meson.build b/meson.build
> > index a72d0c0e85..16928482aa 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -1745,6 +1745,12 @@ if not get_option('driver_qemu').disabled()
> > if use_qemu
> > conf.set('WITH_QEMU', 1)
> > + qemu_moddir = get_option('qemu_moddir')
> > + if qemu_moddir == ''
> > + qemu_moddir = '/usr/lib64/qemu'
> > + endif
> > + conf.set_quoted('QEMU_MODDIR', qemu_moddir)
> > +
> > if host_machine.system() in ['freebsd', 'darwin']
> > default_qemu_user = 'root'
> > default_qemu_group = 'wheel'
> > diff --git a/meson_options.txt b/meson_options.txt
> > index c538d323c1..cedbd79491 100644
> > --- a/meson_options.txt
> > +++ b/meson_options.txt
> > @@ -59,6 +59,7 @@ option('driver_openvz', type: 'feature', value: 'auto', description: 'OpenVZ dri
> > option('driver_qemu', type: 'feature', value: 'auto', description: 'QEMU/KVM driver')
> > option('qemu_user', type: 'string', value: '', description: 'username to run QEMU system instance as')
> > option('qemu_group', type: 'string', value: '', description: 'groupname to run QEMU system instance as')
> > +option('qemu_moddir', type: 'string', value: '', description: 'set the directory where QEMU modules are located')
> > option('driver_remote', type: 'feature', value: 'enabled', description: 'remote driver')
> > option('remote_default_mode', type: 'combo', choices: ['legacy', 'direct'], value: 'legacy', description: 'remote driver default mode')
> > option('driver_secrets', type: 'feature', value: 'auto', description: 'local secrets management driver')
> > diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> > index ff6ba8c9e9..a00853c753 100644
> > --- a/src/qemu/qemu_capabilities.c
> > +++ b/src/qemu/qemu_capabilities.c
> > @@ -677,6 +677,7 @@ struct _virQEMUCaps {
> > char *binary;
> > time_t ctime;
> > time_t libvirtCtime;
> > + time_t modDirMtime;
> > bool invalidation;
> > virBitmapPtr flags;
> > @@ -4194,6 +4195,7 @@ virQEMUCapsParseSEVInfo(virQEMUCapsPtr qemuCaps, xmlXPathContextPtr ctxt)
> > * <qemuCaps>
> > * <emulator>/some/path</emulator>
> > * <qemuctime>234235253</qemuctime>
> > + * <qemumoddirmtime>234235253</qemumoddirmtime>
> > * <selfctime>234235253</selfctime>
> > * <selfvers>1002016</selfvers>
> > * <flag name='foo'/>
> > @@ -4283,6 +4285,9 @@ virQEMUCapsLoadCache(virArch hostArch,
> > }
> > qemuCaps->ctime = (time_t)l;
> > + if (virXPathLongLong("string(./qemumoddirmtime)", ctxt, &l) == 0)
> > + qemuCaps->modDirMtime = (time_t)l;
> > +
> > if ((n = virXPathNodeSet("./flag", ctxt, &nodes)) < 0) {
> > virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> > _("failed to parse qemu capabilities flags"));
> > @@ -4615,6 +4620,10 @@ virQEMUCapsFormatCache(virQEMUCapsPtr qemuCaps)
> > qemuCaps->binary);
> > virBufferAsprintf(&buf, "<qemuctime>%llu</qemuctime>\n",
> > (long long)qemuCaps->ctime);
> > + if (qemuCaps->modDirMtime > 0) {
> > + virBufferAsprintf(&buf, "<qemumoddirmtime>%llu</qemumoddirmtime>\n",
> > + (long long)qemuCaps->modDirMtime);
> > + }
> > virBufferAsprintf(&buf, "<selfctime>%llu</selfctime>\n",
> > (long long)qemuCaps->libvirtCtime);
> > virBufferAsprintf(&buf, "<selfvers>%lu</selfvers>\n",
> > @@ -4881,6 +4890,23 @@ virQEMUCapsIsValid(void *data,
> > if (!qemuCaps->binary)
> > return true;
> > + if (virFileExists(QEMU_MODDIR)) {
> > + if (stat(QEMU_MODDIR, &sb) < 0) {
> > + VIR_DEBUG("Failed to stat QEMU module directory '%s': %s",
> > + QEMU_MODDIR,
> > + g_strerror(errno));
> > + return false;
> > + }
> > +
> > + if (sb.st_mtime != qemuCaps->modDirMtime) {
> > + VIR_DEBUG("Outdated capabilities for '%s': QEMU modules "
> > + "directory '%s' changed (%lld vs %lld)",
> > + qemuCaps->binary, QEMU_MODDIR,
> > + (long long)sb.st_mtime, (long long)qemuCaps->modDirMtime);
> > + return false;
> > + }
> > + }
> > +
> > if (qemuCaps->libvirtCtime != virGetSelfLastChanged() ||
> > qemuCaps->libvirtVersion != LIBVIR_VERSION_NUMBER) {
> > VIR_DEBUG("Outdated capabilities for '%s': libvirt changed "
> > @@ -5463,6 +5489,15 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch,
> > goto error;
> > }
> > + if (virFileExists(QEMU_MODDIR)) {
> > + if (stat(QEMU_MODDIR, &sb) < 0) {
> > + virReportSystemError(errno, _("Cannot check QEMU module directory %s"),
> > + QEMU_MODDIR);
> > + goto error;
> > + }
> > + qemuCaps->modDirMtime = sb.st_mtime;
> > + }
> > +
> > if (virQEMUCapsInitQMP(qemuCaps, libDir, runUid, runGid) < 0)
> > goto error;
> >
>
Regards,
Daniel
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