April 2020 - Devel - libvirt List Archives

[libvirt] [PATCH 00/23] Fix host-model if the chosen CPU model has more features in QEMU compared to our cpu_map.xml
by Jiri Denemark 15 Oct '26

15 Oct '26

When decoding CPUID data to virCPUDef we need to be careful about using a CPU model which cannot be directly used on the current host. Normally, libvirt would notice the features which prevent the model from being usable and it would disable them in the computed virCPUDef, but this won't work in case the definition of the CPU model in QEMU contains more features than what we have in cpu_map.xml. We need to count with the usability blockers we got from QEMU and explicitly disable all of them to make the computed virCPUDef usable. https://bugzilla.redhat.com/show_bug.cgi?id=1464832 Jiri Denemark (23): util: Introduce virStringListCopy conf: Add usability blockers to virDomainCapsCPUModel qemu: Store CPU usability blockers in caps cache qemu: Parse unavailable features for CPU models cpu: Use virDomainCapsCPUModelsPtr in cpu driver APIs cpu: Drop unused parameter from cpuDecode cpu: Return model from virCPUModelIsAllowed cpu_x86: Move x86FeatureFind* to avoid forward prototypes cpu_x86: Disable blockers from unusable CPU models cputest: Replace json bool with enum cputest: Avoid calling json_reformat in cpu-parse.sh cputest: Print correct feature in virCPUUpdateLive test cputest: Test CPU usability blockers cputest: Separate QEMUCaps creation from cpuTestCPUIDJson build: Export virCPUModelIsAllowed private API cputest: Use CPU models from QEMU when available cputest: Add query-cpu-definitions reply for Core-i5-2540M cputest: Add CPUID data for Intel(R) Xeon(R) CPU E7-4830 cputest: Add query-cpu-definitions reply for Xeon-E7-4830 cputest: Update Xeon-E3-1245 data cputest: Add query-cpu-definitions reply for Xeon-E3-1245 cputest: Update Core-i7-2600 data cputest: Make a crippled version of Core-i7-2600 src/conf/domain_capabilities.c | 30 +- src/conf/domain_capabilities.h | 7 +- src/cpu/cpu.c | 95 +- src/cpu/cpu.h | 31 +- src/cpu/cpu_arm.c | 3 +- src/cpu/cpu_ppc64.c | 14 +- src/cpu/cpu_x86.c | 108 +- src/libvirt_private.syms | 1 + src/libxl/libxl_capabilities.c | 2 +- src/libxl/libxl_driver.c | 2 +- src/qemu/qemu_capabilities.c | 123 +-- src/qemu/qemu_capabilities.h | 6 +- src/qemu/qemu_capspriv.h | 5 + src/qemu/qemu_driver.c | 2 +- src/qemu/qemu_monitor.c | 2 + src/qemu/qemu_monitor.h | 1 + src/qemu/qemu_monitor_json.c | 26 +- src/qemu/qemu_process.c | 9 +- src/test/test_driver.c | 2 +- src/util/virstring.c | 37 + src/util/virstring.h | 3 + tests/cputest.c | 324 ++++-- tests/cputestdata/cpu-cpuid.py | 26 +- tests/cputestdata/cpu-gather.sh | 1 + tests/cputestdata/cpu-parse.sh | 2 +- tests/cputestdata/cpu-reformat.py | 9 + tests/cputestdata/x86_64-cpuid-Core-i5-2540M.json | 362 +++++++ .../x86_64-cpuid-Core-i7-2600-disabled.xml | 1 - .../x86_64-cpuid-Core-i7-2600-enabled.xml | 1 + .../cputestdata/x86_64-cpuid-Core-i7-2600-json.xml | 1 + ...x86_64-cpuid-Core-i7-2600-xsaveopt-disabled.xml | 6 + .../x86_64-cpuid-Core-i7-2600-xsaveopt-enabled.xml | 8 + .../x86_64-cpuid-Core-i7-2600-xsaveopt-guest.xml | 25 + .../x86_64-cpuid-Core-i7-2600-xsaveopt-host.xml | 25 + .../x86_64-cpuid-Core-i7-2600-xsaveopt-json.xml | 11 + .../x86_64-cpuid-Core-i7-2600-xsaveopt.json | 615 +++++++++++ .../x86_64-cpuid-Core-i7-2600-xsaveopt.xml | 33 + tests/cputestdata/x86_64-cpuid-Core-i7-2600.json | 496 ++++++++- tests/cputestdata/x86_64-cpuid-Core-i7-2600.xml | 6 +- .../x86_64-cpuid-Xeon-E3-1245-disabled.xml | 1 - .../x86_64-cpuid-Xeon-E3-1245-enabled.xml | 2 +- .../cputestdata/x86_64-cpuid-Xeon-E3-1245-json.xml | 1 + tests/cputestdata/x86_64-cpuid-Xeon-E3-1245.json | 712 +++++++++---- tests/cputestdata/x86_64-cpuid-Xeon-E3-1245.xml | 7 +- .../x86_64-cpuid-Xeon-E7-4830-disabled.xml | 5 + .../x86_64-cpuid-Xeon-E7-4830-enabled.xml | 8 + .../x86_64-cpuid-Xeon-E7-4830-guest.xml | 28 + .../cputestdata/x86_64-cpuid-Xeon-E7-4830-host.xml | 29 + .../cputestdata/x86_64-cpuid-Xeon-E7-4830-json.xml | 14 + tests/cputestdata/x86_64-cpuid-Xeon-E7-4830.json | 657 ++++++++++++ tests/cputestdata/x86_64-cpuid-Xeon-E7-4830.xml | 30 + tests/domaincapstest.c | 6 +- tests/qemucapabilitiesdata/caps_2.10.0.s390x.xml | 1102 ++++++++++++++++++-- tests/qemucapabilitiesdata/caps_2.10.0.x86_64.xml | 236 ++++- tests/qemucapabilitiesdata/caps_2.8.0.x86_64.xml | 154 ++- tests/qemucapabilitiesdata/caps_2.9.0.x86_64.xml | 154 ++- 56 files changed, 4927 insertions(+), 680 deletions(-) create mode 100755 tests/cputestdata/cpu-reformat.py create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt-disabled.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt-enabled.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt-guest.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt-host.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt-json.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt.json create mode 100644 tests/cputestdata/x86_64-cpuid-Core-i7-2600-xsaveopt.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830-disabled.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830-enabled.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830-guest.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830-host.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830-json.xml create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830.json create mode 100644 tests/cputestdata/x86_64-cpuid-Xeon-E7-4830.xml -- 2.14.2

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[Libvir] Hang with virt-install graphic=no on FC 6 6.93/F7 RC2
by libvirtuser 23 Dec '25

23 Dec '25

I had this problem and another user confirmed the same behavior on his machine: http://pastie.caboo.se/65417 Haven't tried it with *2925.10* yet. Also, is there a way to get more verbose info about what calls are causing the "configuration file syntax error" errors? Thanks. virt-install How large would you like the disk () to be (in gigabytes)? 4 ERROR: Must provide a file, not a directory for the disk What would you like to use as the disk (path)? /xen/images/x6.img Would you like to enable graphics support? (yes or no) no What is the install location? http://mirror.anl.gov/pub/fedora-linux-core/test/6.93/Fedora/i386/os/ Starting install... libvir: Xen Daemon error : GET operation failed: libvir: error : configuration file syntax error: expecting a name libvir: error : configuration file syntax error: expecting a name libvir: error : configuration file syntax error: expecting a name Retrieving Fedora... 276 kB 00:01 Retrieving vmlinuz... 100% |=========================| 2.1 MB 00:16 Retrieving initrd.img... 100% |=========================| 5.4 MB 00:28 libvir: Xen Daemon error : GET operation failed: libvir: error : configuration file syntax error: expecting a name libvir: error : configuration file syntax error: expecting a name libvir: error : configuration file syntax error: expecting a name Creating domain... 0 B 00:06 Linux version 2.6.20-2925.5.fc7xen (brewbuilder(a)ls20-bc1-14.build.redhat.com) (gcc version 4.1.2 20070317 (Red Hat 4.1.2-5)) #1 SMP Thu Mar 22 13:51:38 EDT 2007 BIOS-provided physical RAM map: sanitize start sanitize bail 0 copy_e820_map() start: 0000000000000000 size: 0000000020800000 end: 0000000020800000 type: 1 Xen: 0000000000000000 - 0000000020800000 (usable) 0MB HIGHMEM available. 520MB LOWMEM available. Using x86 segment limits to approximate NX protection Zone PFN ranges: DMA 0 -> 133120 Normal 133120 -> 133120 HighMem 133120 -> 133120 early_node_map[1] active PFN ranges 0: 0 -> 133120 ACPI in unprivileged domain disabled Built 1 zonelists. Total pages: 132080 Kernel command line: method=http://mirror.anl.gov/pub/fedora-linux-core/test/6.93/Fedora/i386/os/ Enabling fast FPU save and restore... done. Enabling unmasked SIMD FPU exception support... done. Initializing CPU#0 CPU 0 irqstacks, hard=c135f000 soft=c133f000 PID hash table entries: 4096 (order: 12, 16384 bytes) Xen reported: 1694.994 MHz processor. Console: colour dummy device 80x25 Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar ... MAX_LOCKDEP_SUBCLASSES: 8 ... MAX_LOCK_DEPTH: 30 ... MAX_LOCKDEP_KEYS: 2048 ... CLASSHASH_SIZE: 1024 ... MAX_LOCKDEP_ENTRIES: 8192 ... MAX_LOCKDEP_CHAINS: 16384 ... CHAINHASH_SIZE: 8192 memory used by lock dependency info: 1064 kB per task-struct memory footprint: 1200 bytes Dentry cache hash table entries: 131072 (order: 7, 524288 bytes) Inode-cache hash table entries: 65536 (order: 6, 262144 bytes) Software IO TLB disabled vmalloc area: e1000000-f4ffe000, maxmem 2d7fe000 Memory: 503936k/532480k available (2030k kernel code, 19948k reserved, 1079k data, 180k init, 0k highmem) virtual kernel memory layout: fixmap : 0xf5315000 - 0xf57fe000 (5028 kB) pkmap : 0xf5000000 - 0xf5200000 (2048 kB) vmalloc : 0xe1000000 - 0xf4ffe000 ( 319 MB) lowmem : 0xc0000000 - 0xe0800000 ( 520 MB) .init : 0xc130e000 - 0xc133b000 ( 180 kB) .data : 0xc11fb9d9 - 0xc1309714 (1079 kB) .text : 0xc1000000 - 0xc11fb9d9 (2030 kB) Checking if this processor honours the WP bit even in supervisor mode... Ok. Calibrating delay using timer specific routine.. 4262.67 BogoMIPS (lpj=8525343) Security Framework v1.0.0 initialized SELinux: Initializing. SELinux: Starting in permissive mode selinux_register_security: Registering secondary module capability Capability LSM initialized as secondary Mount-cache hash table entries: 512 CPU: Trace cache: 12K uops, L1 D cache: 8K CPU: L2 cache: 256K Checking 'hlt' instruction... OK. SMP alternatives: switching to UP code Freeing SMP alternatives: 11k freed Brought up 1 CPUs Grant table initialized NET: Registered protocol family 16 Brought up 1 CPUs PCI: Fatal: No config space access function found PCI: setting up Xen PCI frontend stub Setting up standard PCI resources ACPI: Interpreter disabled. Linux Plug and Play Support v0.97 (c) Adam Belay pnp: PnP ACPI: disabled xen_mem: Initialising balloon driver. usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb PCI: System does not support PCI PCI: System does not support PCI NetLabel: Initializing NetLabel: domain hash size = 128 NetLabel: protocols = UNLABELED CIPSOv4 NetLabel: unlabeled traffic allowed by default NET: Registered protocol family 2 IP route cache hash table entries: 32768 (order: 5, 131072 bytes) TCP established hash table entries: 131072 (order: 10, 4194304 bytes) TCP bind hash table entries: 65536 (order: 9, 2097152 bytes) TCP: Hash tables configured (established 131072 bind 65536) TCP reno registered checking if image is initramfs... it is Freeing initrd memory: 7256k freed IA-32 Microcode Update Driver: v1.14-xen <tigran(a)veritas.com> audit: initializing netlink socket (disabled) audit(1180379657.981:1): initialized VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) SELinux: Registering netfilter hooks io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) pci_hotplug: PCI Hot Plug PCI Core version: 0.5 BUG: at kernel/fork.c:994 copy_process() [<c1005d9a>] show_trace_log_lvl+0x1a/0x2f [<c1006343>] show_trace+0x12/0x14 [<c10063be>] dump_stack+0x16/0x18 [<c101d044>] copy_process+0x195/0x1245 [<c101e144>] do_fork+0x50/0x117 [<c1003351>] kernel_thread+0x8e/0x96 [<c102c701>] __call_usermodehelper+0x2d/0x46 [<c102cd4f>] run_workqueue+0x89/0x145 [<c102d711>] worker_thread+0xd5/0x102 [<c102ff27>] kthread+0xb3/0xdc [<c10058db>] kernel_thread_helper+0x7/0x10 ======================= rtc: IRQ 8 is not free. Non-volatile memory driver v1.2 Linux agpgart interface v0.101 (c) Dave Jones RAMDISK driver initialized: 16 RAM disks of 16384K size 4096 blocksize input: Macintosh mouse button emulation as /class/input/input0 Xen virtual console successfully installed as xvc0 Event-channel device installed. usbcore: registered new interface driver libusual usbcore: registered new interface driver hiddev usbcore: registered new interface driver usbhid drivers/usb/input/hid-core.c: v2.6:USB HID core driver PNP: No PS/2 controller found. Probing ports directly. i8042.c: No controller found. mice: PS/2 mouse device common for all mice TCP bic registered Initializing XFRM netlink socket NET: Registered protocol family 1 NET: Registered protocol family 17 Using IPI No-Shortcut mode XENBUS: Device with no driver: device/vbd/51712 XENBUS: Device with no driver: device/vif/0 Freeing unused kernel memory: 180k freed Write protecting the kernel read-only data: 762k ^[Domain installation still in progress. You can reconnect

2 1

[libvirt] [PATCH] Fix python error reporting for some storage operations
by Cole Robinson 07 Mar '25

07 Mar '25

In the python bindings, all vir* classes expect to be passed a virConnect object when instantiated. Before the storage stuff, these classes were only instantiated in virConnect methods, so the generator is hardcoded to pass 'self' as the connection instance to these classes. Problem is there are some methods that return pool or vol instances which aren't called from virConnect: you can lookup a storage volume's associated pool, and can lookup volumes from a pool. In these cases passing 'self' doesn't give the vir* instance a connection, so when it comes time to raise an exception crap hits the fan. Rather than rework the generator to accomodate this edge case, I just fixed the init functions for virStorage* to pull the associated connection out of the passed value if it's not a virConnect instance. Thanks, Cole diff --git a/python/generator.py b/python/generator.py index 01a17da..c706b19 100755 --- a/python/generator.py +++ b/python/generator.py @@ -962,8 +962,12 @@ def buildWrappers(): list = reference_keepers[classname] for ref in list: classes.write(" self.%s = None\n" % ref[1]) - if classname in [ "virDomain", "virNetwork", "virStoragePool", "virStorageVol" ]: + if classname in [ "virDomain", "virNetwork" ]: classes.write(" self._conn = conn\n") + elif classname in [ "virStorageVol", "virStoragePool" ]: + classes.write(" self._conn = conn\n" + \ + " if not isinstance(conn, virConnect):\n" + \ + " self._conn = conn._conn\n") classes.write(" if _obj != None:self._o = _obj;return\n") classes.write(" self._o = None\n\n"); destruct=None

4 3

Re: [libvirt] [Qemu-devel] Qemu migration with vhost-user-blk on top of local storage
by Stefan Hajnoczi 27 Oct '23

27 Oct '23

On Wed, Jan 09, 2019 at 06:23:42PM +0800, wuzhouhui wrote: > Hi everyone, > > I'm working qemu with vhost target (e.g. spdk), and I attempt to migrate VM with > 2 local storages. One local storage is a regular file, e.g. /tmp/c74.qcow2, and > the other is a malloc bdev that spdk created. This malloc bdev will exported to > VM via vhost-user-blk. When I execute following command: > > virsh migrate --live --persistent --unsafe --undefinesource --copy-storage-all \ > --p2p --auto-converge --verbose --desturi qemu+tcp://<uri>/system vm0 > > The libvirt reports: > > qemu-2.12.1: error: internal error: unable to execute QEMU command \ > 'nbd-server-add': Cannot find device=drive-virtio-disk1 nor \ > node_name=drive-virtio-disk1 Please post your libvirt domain XML. > Does it means that qemu with spdk on top of local storage don't support migration? > > QEMU: 2.12.1 > SPDK: 18.10 vhost-user-blk bypasses the QEMU block layer, so NBD storage migration at the QEMU level will not work for the vhost-user-blk disk. Stefan

4 4

[libvirt] [PATCH v3] openvswitch: Add new port VLAN mode "dot1q-tunnel"
by luzhipeng＠uniudc.com 27 Oct '23

27 Oct '23

From: ZhiPeng Lu <luzhipeng(a)uniudc.com> Signed-off-by: ZhiPeng Lu <luzhipeng(a)uniudc.com> --- v1->v2: 1. Fix "make syntax-check" failure v2->v3: 1. remove other_config when updating vlan docs/formatnetwork.html.in | 17 +++++++++-------- docs/schemas/networkcommon.rng | 1 + src/conf/netdev_vlan_conf.c | 2 +- src/util/virnetdevopenvswitch.c | 7 +++++++ src/util/virnetdevvlan.h | 1 + 5 files changed, 19 insertions(+), 9 deletions(-) diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in index 363a72b..3c1ae62 100644 --- a/docs/formatnetwork.html.in +++ b/docs/formatnetwork.html.in @@ -688,16 +688,17 @@ For network connections using Open vSwitch it is also possible - to configure 'native-tagged' and 'native-untagged' VLAN modes + to configure 'native-tagged' and 'native-untagged' and 'dot1q-tunnel' + VLAN modes. Since 1.1.0. This is done with the - optional <code>nativeMode</code> attribute on - the <code><tag></code> subelement: <code>nativeMode</code> - may be set to 'tagged' or 'untagged'. The <code>id</code> - attribute of the <code><tag></code> subelement - containing <code>nativeMode</code> sets which VLAN is considered - to be the "native" VLAN for this interface, and + optional <code>nativeMode</code> attribute on the + <code><tag></code> subelement: <code>nativeMode</code> + may be set to 'tagged' or 'untagged' or 'dot1q-tunnel'. + The <code>id</code> attribute of the <code><tag></code> + subelement containing <code>nativeMode</code> sets which VLAN is + considered to be the "native" VLAN for this interface, and the <code>nativeMode</code> attribute determines whether or not - traffic for that VLAN will be tagged. + traffic for that VLAN will be tagged or QinQ. <code><vlan></code> elements can also be specified in diff --git a/docs/schemas/networkcommon.rng b/docs/schemas/networkcommon.rng index 2699555..11c48ff 100644 --- a/docs/schemas/networkcommon.rng +++ b/docs/schemas/networkcommon.rng @@ -223,6 +223,7 @@ <choice> <value>tagged</value> <value>untagged</value> + <value>dot1q-tunnel</value> </choice> </attribute> </optional> diff --git a/src/conf/netdev_vlan_conf.c b/src/conf/netdev_vlan_conf.c index dff49c6..79710d9 100644 --- a/src/conf/netdev_vlan_conf.c +++ b/src/conf/netdev_vlan_conf.c @@ -29,7 +29,7 @@ #define VIR_FROM_THIS VIR_FROM_NONE VIR_ENUM_IMPL(virNativeVlanMode, VIR_NATIVE_VLAN_MODE_LAST, - "default", "tagged", "untagged") + "default", "tagged", "untagged", "dot1q-tunnel") int virNetDevVlanParse(xmlNodePtr node, xmlXPathContextPtr ctxt, virNetDevVlanPtr def) diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c index 8fe06fd..9fec30b 100644 --- a/src/util/virnetdevopenvswitch.c +++ b/src/util/virnetdevopenvswitch.c @@ -91,6 +91,11 @@ virNetDevOpenvswitchConstructVlans(virCommandPtr cmd, virNetDevVlanPtr virtVlan) virCommandAddArg(cmd, "vlan_mode=native-untagged"); virCommandAddArgFormat(cmd, "tag=%d", virtVlan->nativeTag); break; + case VIR_NATIVE_VLAN_MODE_DOT1Q_TUNNEL: + virCommandAddArg(cmd, "vlan_mode=dot1q-tunnel"); + virCommandAddArg(cmd, "other_config:qinq-ethtype=802.1q"); + virCommandAddArgFormat(cmd, "tag=%d", virtVlan->nativeTag); + break; case VIR_NATIVE_VLAN_MODE_DEFAULT: default: break; @@ -504,6 +509,8 @@ int virNetDevOpenvswitchUpdateVlan(const char *ifname, "--", "--if-exists", "clear", "Port", ifname, "tag", "--", "--if-exists", "clear", "Port", ifname, "trunk", "--", "--if-exists", "clear", "Port", ifname, "vlan_mode", + "--", "--if-exists", "remove", "Port", ifname, "other_config", + "qinq-ethtype", NULL, "--", "--if-exists", "set", "Port", ifname, NULL); if (virNetDevOpenvswitchConstructVlans(cmd, virtVlan) < 0) diff --git a/src/util/virnetdevvlan.h b/src/util/virnetdevvlan.h index be85f59..0667f9d 100644 --- a/src/util/virnetdevvlan.h +++ b/src/util/virnetdevvlan.h @@ -29,6 +29,7 @@ typedef enum { VIR_NATIVE_VLAN_MODE_DEFAULT = 0, VIR_NATIVE_VLAN_MODE_TAGGED, VIR_NATIVE_VLAN_MODE_UNTAGGED, + VIR_NATIVE_VLAN_MODE_DOT1Q_TUNNEL, VIR_NATIVE_VLAN_MODE_LAST } virNativeVlanMode; -- 1.8.3.1

3 2

[libvirt] [PATCH] Fix compile error for stable 1.2.9
by Yang hongyang 27 Oct '23

27 Oct '23

Seems a backport miss. An extra member is passed to struct virLXCBasicMountInfo. Signed-off-by: Yang hongyang <hongyang.yang(a)easystack.cn> --- src/lxc/lxc_container.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 28dabec..1c65fa9 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -760,7 +760,7 @@ typedef struct { static const virLXCBasicMountInfo lxcBasicMounts[] = { { "proc", "/proc", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, false, false }, - { "/proc/sys", "/proc/sys", NULL, MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false, false }, + { "/proc/sys", "/proc/sys", NULL, MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false }, { "sysfs", "/sys", "sysfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false }, { "securityfs", "/sys/kernel/security", "securityfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, true, true }, #if WITH_SELINUX -- 1.7.1

3 2

[libvirt] [PATCH] web docs -- macvtap mode explanation
by Stefan Berger 27 Oct '23

27 Oct '23

This adds more information about the different macvtap device modes. Regards, Stefan

3 2

[libvirt] Supporting vhost-net and macvtap in libvirt for QEMU
by Anthony Liguori 27 Oct '23

27 Oct '23

Disclaimer: I am neither an SR-IOV nor a vhost-net expert, but I've CC'd people that are who can throw tomatoes at me for getting bits wrong :-) I wanted to start a discussion about supporting vhost-net in libvirt. vhost-net has not yet been merged into qemu but I expect it will be soon so it's a good time to start this discussion. There are two modes worth supporting for vhost-net in libvirt. The first mode is where vhost-net backs to a tun/tap device. This is behaves in very much the same way that -net tap behaves in qemu today. Basically, the difference is that the virtio backend is in the kernel instead of in qemu so there should be some performance improvement. Current, libvirt invokes qemu with -net tap,fd=X where X is an already open fd to a tun/tap device. I suspect that after we merge vhost-net, libvirt could support vhost-net in this mode by just doing -net vhost,fd=X. I think the only real question for libvirt is whether to provide a user visible switch to use vhost or to just always use vhost when it's available and it makes sense. Personally, I think the later makes sense. The more interesting invocation of vhost-net though is one where the vhost-net device backs directly to a physical network card. In this mode, vhost should get considerably better performance than the current implementation. I don't know the syntax yet, but I think it's reasonable to assume that it will look something like -net tap,dev=eth0. The effect will be that eth0 is dedicated to the guest. On most modern systems, there is a small number of network devices so this model is not all that useful except when dealing with SR-IOV adapters. In that case, each physical device can be exposed as many virtual devices (VFs). There are a few restrictions here though. The biggest is that currently, you can only change the number of VFs by reloading a kernel module so it's really a parameter that must be set at startup time. I think there are a few ways libvirt could support vhost-net in this second mode. The simplest would be to introduce a new tag similar to <source network='br0'>. In fact, if you probed the device type for the network parameter, you could probably do something like <source network='eth0'> and have it Just Work. Another model would be to have libvirt see an SR-IOV adapter as a network pool whereas it handled all of the VF management. Considering how inflexible SR-IOV is today, I'm not sure whether this is the best model. Has anyone put any more thought into this problem or how this should be modeled in libvirt? Michael, could you share your current thinking for -net syntax? -- Regards, Anthony Liguori

8 26

[libvirt] Semantic change in v4.3 slows down image creation and snapshots (on ZFS)
by Christian Ehrhardt 31 Jul '22

31 Jul '22

Hi, when discussing bug [1] triggered by [2] Daniel and I have found that the change [3] which is in since v4.3 was a semantic change to the behavior of libvirt. virt-manager used and still does issue a volume XML like: <volume> <name>disk.qcow2</name> <capacity>16106127360</capacity> <allocation>16106127360</allocation> <target> <format type="qcow2"/> <features> <lazy_refcounts/> </features> </target> </volume> Up until the commit above that was using preallocation=metadata, but now uses preallocation=falloc. In many cases (read: Fileystems) that won't be very user-visible, but if you are running on ZFS (or anything else that can't fallocate well) this is made worse by [4] slowing down these operations a lot. After the POV for virt-manager seems to have settled on the bug [1] referenced the remaining question is if libvirt should revert/modify the change [3] - and that we agreed required a wider discussion to be had here, hence this mail. [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1759454 [2]: https://bugs.launchpad.net/virt-manager/+bug/1847105 [3]: https://libvirt.org/git/?p=libvirt.git;a=commit;h=c9ec7088c7a3f4cd26bb471f1… [4]: https://github.com/zfsonlinux/zfs/issues/326 -- Christian Ehrhardt Software Engineer, Ubuntu Server Canonical Ltd

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Races / crashes in shutdown of libvirtd daemon
by Daniel P. Berrangé 13 Nov '20

13 Nov '20

We got a new BZ filed about a libvirtd crash in shutdown https://bugzilla.redhat.com/show_bug.cgi?id=1828207 We can see from the stack trace that the "interface" driver is in the middle of servicing an RPC call for virConnectListAllInterfaces() Meanwhile the libvirtd daemon is doing virObjectUnref(dmn) on the virNetDaemonPtr object. The fact that it is doing this unref, means that it must have already call virStateCleanup(), given the code sequence: /* Run event loop. */ virNetDaemonRun(dmn); ret = 0; virHookCall(VIR_HOOK_DRIVER_DAEMON, "-", VIR_HOOK_DAEMON_OP_SHUTDOWN, 0, "shutdown", NULL, NULL); cleanup: /* Keep cleanup order in inverse order of startup */ virNetDaemonClose(dmn); virNetlinkEventServiceStopAll(); if (driversInitialized) { /* NB: Possible issue with timing window between driversInitialized * setting if virNetlinkEventServerStart fails */ driversInitialized = false; virStateCleanup(); } virObjectUnref(adminProgram); virObjectUnref(srvAdm); virObjectUnref(qemuProgram); virObjectUnref(lxcProgram); virObjectUnref(remoteProgram); virObjectUnref(srv); virObjectUnref(dmn); Unless I'm missing something non-obvious, this cleanup code path is inherantly broken & racy. When virNetDaemonRun() returns the RPC worker threads are all still active. They are all liable to still be executing RPC calls, which means any of the drivers may be in use. So calling virStateCleanup() is an inherantly dangerous thing to do. There is the further complication that once we have exitted the main loop we may prevent the RPC calls from ever completing, as they may be waiting on an event to be dispatched. I know we're had various patch proposals in the past to improve the robustness of shutdown cleanup but I can't remember the outcome of the reviews. Hopefully people involved in those threads can jump in here... IMHO the key problem here is the virNetDeamonRun() method which just looks at the "quit" flag and immediately returns if it is set. This needs to be changed so that when it sees quit == true, it takes the following actions 1. Call virNetDaemonClose() to drop all RPC clients and thus prevent new RPC calls arriving 2. Flush any RPC calls which are queued but not yet assigned to a worker thread 3. Tell worker threads to exit after finishing their current job 4. Wait for all worker threads to exit 5. Now virNetDaemonRun may return At this point we can call virStateCleanup and the various other things, as we know no drivers are still active in RPC calls. Having said that, there could be background threads in the the drivers which are doing work that uses the event loop thread. So we probably need a virStateClose() method that we call from virNetDaemonRun, *after* all worker threads are gone, which would cleanup any background threads while the event loop is still running. The issue is that step 4 above ("Wait for all worker threads to exit") may take too long, or indeed never complete. To deal with this, it will need a timeout. In the remote_daemon.c cleanup code path, if there are still worker threads present, then we need to skip all cleanup and simply call _exit(0) to terminate the process with no attempt at cleanup, since it would be unsafe to try anything else. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|

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