libvirt hook to change domain xml
by Victor Toso
Hi,
I'm particularly interested in the PoC of KubeVirt to allow
custom changes in libvirt domain xml in a more straightforward
manner than they have Today [0].
When I was looking into the libvirt hooks, I was a bit excited
when I read:
> you can also place several hook scripts in the directory
> /etc/libvirt/hooks/qemu.d/. They are executed in alphabetical
> order after main script. In this case each script also acts as
> filter and can modify the domain XML and print it out on its
> standard output. This script output is passed to standard
> input next script in order. Empty output from any script is
> also identical to copying the input XML without changing it.
> In case any script returns failure common process will be
> aborted, but all scripts from the directory will are executed.
But that's not the case for every situation. When the domain is
being defined the scripts are run but the output is ignored [1]
Is there a reason for that?
In KubeVirt we basically have to re-implement [2] what the logic
around scripts under qemu.d already does. If we could use libvirt
only it would make testing easier for users and less code on
KubeVirt.
[0] https://kubevirt.io/user-guide/user_workloads/hook-sidecar/
[1] https://gitlab.com/libvirt/libvirt/-/blob/master/src/qemu/qemu_process.c#...
[2] https://github.com/kubevirt/kubevirt/blob/main/pkg/hooks/manager.go#L200
Cheers,
Victor
3 months, 3 weeks
[PATCH 00/12] [PATCH v2 00/12] qemu: support passt as a backend for vhost-user network interfaces
by Laine Stump
====
Changes from V1:
* fixed missing change to error log message pointed out by abologna
* added a validation check to assure that shared memory is enabled
if there is a type='vhostuser' interface in the domain definition
* included a patch documenting differences between type='user' SLIRP
and passt behaviors (because I had to do it anyway, and the
reorganization made documenting type='vhostuser' passt slightly
easier.
* added documentation for type='vhostuser' backend type='passt'
=====
passt (https://passt.top) provides a method of connecting QEMU virtual
machines to the external network without requiring special privileges
or capabilities of any participating processes - even libvirt itself
can run unprivileged and create an instance of passt (which *always*
runs unprivileged) that is then connected to the qemu process (and
thus the virtual machine) with a unix socket.
Originally passt used its own protocol for this socket, sending both
control messages and data packets over the socket. This works, and is
already much more efficient than the previously
only-unprivileged-networking-solution slirp.
But recently passt added support for using the vhost-user protocol for
communication between the passt process (which is connected to the
external network) and the QEMU process (and thus the VM). vhost-user
also uses a unix socket, but only for control plane messages - all
data packets are "sent" between the VM and passt process via a shared
memory region. This is unsurprisingly much more efficient.
From the point of view of QEMU, the passt process looks identical to
any normal vhost-user backend, so we can run QEMU with exactly the
same interface commandline options as normal vhost-user. Also, the
passt process supports all of the same options as it does when used in
its "traditional" mode, so really in the end all we need to do is
twist libvirt around so that when <backend type='passt'/> is specified
for an <interface type='vhostuser'>, it will run passt just as before
(except with the added "--vhost-user" option so that passt will know
to use that), and then force feed the vhost-user code in libvirt with
the same socket path used by passt.
This series does that, while also switching up a few bits of code
prior to adding in the new functionality.
So far this has been tested both unprivileged and privileged on Fedora
40 (with latest passt packet) and selinux enabled (there are a couple
of selinux policy tweaks that still need to be pushed to
passt-selinux) as well as unprivileged on debian (I *think* with
AppArmor enabled) and everything seems to work.
(I haven't gotten to testing hotplug, but it *should* work, and I'll
be testing it while (hopefully) someone is reviewing these patches.)
To test, you will need the latest (20250121) passt package and the
aforementioned upstream passt-selinux patch if you're using selinux.
This Resolves: https://issues.redhat.com/browse/RHEL-69455
Laine Stump (12):
conf: change virDomainHostdevInsert() to return void
qemu: fix qemu validation to forbid guest-side IP address for
type='vdpa'
qemu: validate that model is virtio for vhostuser and vdpa interfaces
in the same place
qemu: automatically set model type='virtio' for interface
type='vhostuser'
qemu: do all vhostuser attribute validation in qemu driver
conf/qemu: make <source> element *almost* optional for type=vhostuser
qemu: use switch instead of if in qemuProcessPrepareDomainNetwork()
qemu: make qemuPasstCreateSocketPath() public
qemu: complete vhostuser + passt support
qemu: fail validation if a domain def has vhostuser/passt but no
shared mem
docs: improve type='user' docs to higlight differences between SLIRP
and passt
docs: document using passt backend with <interface type='vhostuser'>
docs/formatdomain.rst | 189 +++++++++++++-----
src/conf/domain_conf.c | 107 +++++-----
src/conf/domain_conf.h | 2 +-
src/conf/domain_validate.c | 85 +++-----
src/conf/schemas/domaincommon.rng | 32 ++-
src/libxl/libxl_domain.c | 5 +-
src/libxl/libxl_driver.c | 3 +-
src/lxc/lxc_driver.c | 3 +-
src/qemu/qemu_command.c | 7 +-
src/qemu/qemu_driver.c | 3 +-
src/qemu/qemu_extdevice.c | 6 +-
src/qemu/qemu_hotplug.c | 21 +-
src/qemu/qemu_passt.c | 5 +-
src/qemu/qemu_passt.h | 3 +
src/qemu/qemu_postparse.c | 3 +-
src/qemu/qemu_process.c | 85 +++++---
src/qemu/qemu_validate.c | 65 ++++--
...t-user-slirp-portforward.x86_64-latest.err | 2 +-
...vhostuser-passt-no-shmem.x86_64-latest.err | 1 +
.../net-vhostuser-passt-no-shmem.xml | 70 +++++++
.../net-vhostuser-passt.x86_64-latest.args | 42 ++++
.../net-vhostuser-passt.x86_64-latest.xml | 75 +++++++
tests/qemuxmlconfdata/net-vhostuser-passt.xml | 73 +++++++
tests/qemuxmlconftest.c | 2 +
24 files changed, 657 insertions(+), 232 deletions(-)
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt-no-shmem.x86_64-latest.err
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt-no-shmem.xml
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.xml
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt.xml
--
2.47.1
3 months, 3 weeks
[PATCH] build-aux: squelch trailing blank warnings from binary files
by Daniel P. Berrangé
These files pollute the stderr output when the sc_trailing_blank
syntax check fails.
Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com>
---
build-aux/syntax-check.mk | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/build-aux/syntax-check.mk b/build-aux/syntax-check.mk
index e6afb879be..bd3dd6cb54 100644
--- a/build-aux/syntax-check.mk
+++ b/build-aux/syntax-check.mk
@@ -1438,7 +1438,7 @@ exclude_file_name_regexp--sc_require_config_h_first = \
^(examples/|tools/virsh-edit\.c$$|tests/virmockstathelpers\.c$$|scripts/rpcgen/tests/test_demo\.c$$)
exclude_file_name_regexp--sc_trailing_blank = \
- /sysinfodata/.*\.data|/virhostcpudata/.*\.cpuinfo|tests/virshtestdata/.*$$
+ /sysinfodata/.*\.data|/virhostcpudata/.*\.cpuinfo|tests/virshtestdata/.*|docs/fonts|scripts/rpcgen/tests/.*\.bin|tests/viracpidata/.*|tests/virpcitestdata/*|tests/virstoragetestdata/images/.*\.qcow2$$
exclude_file_name_regexp--sc_unmarked_diagnostics = \
^(scripts/apibuild.py|tests/virt-aa-helper-test|docs/js/.*\.js)$$
--
2.47.1
3 months, 3 weeks
[PATCH] qemu: Avoid crash in qemuDomainCheckCPU with unknown host CPU
by Jiri Denemark
When we don't have any information about host CPU (for example when
running on an aarch64 host), the virQEMUCapsGetHostModel would return
NULL.
Fixes: https://gitlab.com/libvirt/libvirt/-/issues/747
Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com>
---
src/qemu/qemu_domain.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index cf05dca55a..df1ed0223d 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -11430,6 +11430,7 @@ qemuDomainCheckCPU(virArch arch,
/* Force compat check if the CPU model is not found in qemuCaps or
* we don't have host CPU data from QEMU */
if (!cpu->model ||
+ !hypervisorCPU ||
hypervisorCPU->fallback != VIR_CPU_FALLBACK_FORBID ||
virQEMUCapsGetCPUBlockers(qemuCaps, virtType,
cpu->model, &blockers) < 0)
--
2.48.1
3 months, 3 weeks
Plans for 11.1.0 release (freeze on Monday 24 Feb)
by Jiri Denemark
We are getting close to 11.1.0 release of libvirt. To aim for the
release on Monday 03 Mar I suggest entering the freeze on Monday 24
Feb and tagging RC2 on Thursday 27 Feb.
I hope this works for everyone.
Jirka
3 months, 3 weeks
[PATCH] util: fix compile warning in virsystemd.c during mingw builds
by Laine Stump
A function was changed from having no arguments to having a single
argument, but the entire body of the function was #ifdefed out for
windows builds, leaving that new argument unused. Surprisingly this
didn't cause the build to fail, but I happened to notice it flit by
during an rpm build.
Fixes: 785cd56e5803fbbf60715fb6c7536360df5b4b9e
Signed-off-by: Laine Stump <laine(a)redhat.com>
---
I'm pushing this as trivial (technically it's not a build breaker,
since the build still continues even with the warning :-P)
src/util/virsystemd.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c
index 57fe409c57..92d2890360 100644
--- a/src/util/virsystemd.c
+++ b/src/util/virsystemd.c
@@ -624,10 +624,15 @@ int virSystemdTerminateMachine(const char *name)
return 0;
}
+#ifdef WIN32
+static void
+virSystemdNotify(const char *msg G_GNUC_UNUSED)
+{
+}
+#else
static void
virSystemdNotify(const char *msg)
{
-#ifndef WIN32
const char *path;
int fd;
struct sockaddr_un un = {
@@ -672,8 +677,8 @@ virSystemdNotify(const char *msg)
VIR_WARN("Failed to notify systemd");
VIR_FORCE_CLOSE(fd);
-#endif /* !WIN32 */
}
+#endif /* !WIN32 */
void virSystemdNotifyReady(void)
{
--
2.47.1
3 months, 3 weeks
[PATCH] utils: Canonicalize paths before comparing them
by Andrea Bolognani
Resolves: https://issues.redhat.com/browse/RHEL-79165
Signed-off-by: Andrea Bolognani <abologna(a)redhat.com>
---
src/util/virfile.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 6ac0f4efb3..7cab3d0cd6 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -3823,10 +3823,13 @@ virFileIsSharedFSOverride(const char *path,
if (!path || path[0] != '/' || !overrides)
return false;
- if (g_strv_contains((const char *const *) overrides, path))
- return true;
+ /* Overrides have been canonicalized ahead of time, so we need to
+ * do the same for the provided path or we'll never be able to
+ * find a match if symlinks are involved */
+ dirpath = virFileCanonicalizePath(path);
- dirpath = g_strdup(path);
+ if (g_strv_contains((const char *const *) overrides, dirpath))
+ return true;
/* Continue until we've scanned the entire path */
while (p != dirpath) {
--
2.48.1
3 months, 3 weeks
[PATCH 0/2] qemu: Support specifying save image format
by Jim Fehlig
This series is based on a cleanup of qemuSaveImageGetCompressionProgram [1]
and demonstrates the usefulness of that cleanup. Patch1 adds the
VIR_DOMAIN_SAVE_PARAM_IMAGE_FORMAT typed parameter to virDomainSaveParams,
allowing to specify the image format on a per-operation basis. The format
can still be set driver-wide in qemu.conf. Patch2 provides the
implementation in the qemu driver.
[1] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/SK...
Jim Fehlig (2):
include: Define constant for save image format
qemu: Add support for 'image_format' typed parameter
include/libvirt/libvirt-domain.h | 13 +++++++++++++
src/libvirt-domain.c | 3 +++
src/qemu/qemu_driver.c | 12 ++++++++++--
3 files changed, 26 insertions(+), 2 deletions(-)
--
2.43.0
3 months, 3 weeks
[PATCH 0/3] qemu: Small cleanups to SaveImageGetCompressionProgram and callers
by Jim Fehlig
Even though my work on supporting mapped-ram is the main motivation for
this small cleanup series, IMO is useful in its own right.
Jim Fehlig (3):
qemu: Move declaration of virQEMUSaveFormat to header file
qemu: Move special handling of invalid dump format to only caller
qemu: Change return value of SaveImageGetCompressionProgram
src/qemu/qemu_driver.c | 52 ++++++++++++++--------
src/qemu/qemu_saveimage.c | 92 +++++++--------------------------------
src/qemu/qemu_saveimage.h | 24 ++++++++--
src/qemu/qemu_snapshot.c | 11 +++--
4 files changed, 78 insertions(+), 101 deletions(-)
--
2.43.0
3 months, 3 weeks
[PATCH 0/9] qemu: support passt as the backend for vhost-user network interfaces
by Laine Stump
passt (https://passt.top) provides a method of connecting QEMU virtual
machines to the external network without requiring special privileges
or capabilities of any participating processes - even libvirt itself
can run unprivileged and create an instance of passt (which *always*
runs unprivileged) that is then connected to the qemu process (and
thus the virtual machine) with a unix socket.
Originally passt used its own protocol for this socket, sending both
control messages and data packets over the socket. This works, and is
already much more efficient than the previously
only-unprivileged-networking-solution slirp.
But recently passt added support for using the vhost-user protocol for
communication between the passt process (which is connected to the
external network) and the QEMU process (and thus the VM). vhost-user
also uses a unix socket, but only for control plane messages - all
data packets are "sent" between the VM and passt process via a shared
memory region. This is unsurprisingly much more efficient.
From the point of view of QEMU, the passt process looks identical to
any normal vhost-user backend, so we can run QEMU with exactly the
same interface commandline options as normal vhost-user. Also, the
passt process supports all of the same options as it does when used in
its "traditional" mode, so really in the end all we need to do is
twist libvirt around so that when <backend type='passt'/> is specified
for an <interface type='vhostuser'>, it will run passt just as before
(except with the added "--vhost-user" option so that passt will know
to use that), and then force feed the vhost-user code in libvirt with
the same ocket path used by passt.
This series does that, while also switching up a few bits of code
prior to adding in the new functionality.
So far this has been tested both unprivileged and privileged on Fedora
40 (with latest passt packet) and selinux enabled (there are a couple
of selinux policy tweaks that still need to be pushed to
passt-selinux) as well as unprivileged on debian (I *think* with
AppArmor enabled) and everything seems to work.
(I haven't gotten to testing hotplug, but it *should* work, and I'll
be testing it while (hopefully) someone is reviewing these patches.)
I also need to make the patch to update formatdomain.rst before the
rest of it can be pushed, but I wanted to get this posted to save time
later.
This series does require patch 1 of the series I posted a couple days
ago that changes several functions that can't fail to return void.
Also, you will need the latest (20250121) passt package.
This Resolves: https://issues.redhat.com/browse/RHEL-69455
Laine Stump (9):
conf: change virDomainHostdevInsert() to return void
qemu: fix qemu validation to forbid guest-side IP address for
type='vdpa'
qemu: validate that model is virtio for vhostuser and vdpa interfaces
in the same place
qemu: automatically set model type='virtio' for interface
type='vhostuser'
qemu: do all vhostuser attribute validation in qemu driver
conf/qemu: make <source> element *almost* optional for type=vhostuser
qemu: use switch instead of if in qemuProcessPrepareDomainNetwork()
qemu: make qemuPasstCreateSocketPath() public
qemu: complete vhostuser + passt support
src/conf/domain_conf.c | 107 +++++++++---------
src/conf/domain_conf.h | 2 +-
src/conf/domain_validate.c | 83 ++++----------
src/conf/schemas/domaincommon.rng | 32 +++++-
src/libxl/libxl_domain.c | 5 +-
src/libxl/libxl_driver.c | 3 +-
src/lxc/lxc_driver.c | 3 +-
src/qemu/qemu_command.c | 7 +-
src/qemu/qemu_driver.c | 3 +-
src/qemu/qemu_extdevice.c | 6 +-
src/qemu/qemu_hotplug.c | 21 +++-
src/qemu/qemu_passt.c | 5 +-
src/qemu/qemu_passt.h | 3 +
src/qemu/qemu_postparse.c | 3 +-
src/qemu/qemu_process.c | 84 +++++++++-----
src/qemu/qemu_validate.c | 56 ++++++---
...t-user-slirp-portforward.x86_64-latest.err | 2 +-
.../net-vhostuser-passt.x86_64-latest.args | 42 +++++++
.../net-vhostuser-passt.x86_64-latest.xml | 72 ++++++++++++
tests/qemuxmlconfdata/net-vhostuser-passt.xml | 70 ++++++++++++
tests/qemuxmlconftest.c | 1 +
21 files changed, 429 insertions(+), 181 deletions(-)
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.xml
create mode 100644 tests/qemuxmlconfdata/net-vhostuser-passt.xml
--
2.47.1
4 months
