Ubuntu
libvirt package

XML error: No PCI buses available when defining MIPS VM

Bug #1561497 reported by Magnus
24
This bug affects 4 people
Affects Status Importance Assigned to Milestone
libvirt
Confirmed
Undecided
libvirt (Ubuntu)
Won't Fix
Undecided
Unassigned

Bug Description

When trying to define a VM using mips64el architecture, I get the following error message from virsh:

XML error: No PCI buses available

Using virt-manager results in a similar error message.

XML file used:

<domain type='qemu' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
  <name>qemu-malta</name>
  <memory unit='KiB'>2097152</memory>
  <currentMemory unit='KiB'>2097152</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <resource>
    <partition>/machine</partition>
  </resource>
  <os>
    <type arch='mips64el' machine='malta'>hvm</type>
    <kernel>/tmp/qemu.elf</kernel>
    <boot dev='hd'/>
  </os>
  <cpu mode='custom' match='exact'>
    <model fallback='allow'>R4000</model>
  </cpu>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-system-mips64el</emulator>
    <interface type='bridge' trustGuestRxFilters='yes'>
      <source bridge='br0'/>
      <virtualport type='openvswitch'>
      </virtualport>
      <model type='virtio'/>
      <address type='virtio-mmio'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <memballoon model='none'/>
  </devices>
  <qemu:commandline>
    <qemu:arg value='-s'/>
  </qemu:commandline>
</domain>

Description: Ubuntu Xenial Xerus (development branch)
Release: 16.04

libvirt-bin:
  Installed: 1.3.1-1ubuntu6
  Candidate: 1.3.1-1ubuntu6

Revision history for this message
In , Ian (ian-redhat-bugs) wrote :

Trying to create a MIPS guest via virt-manager and getting this error:

Unable to complete install: 'XML error: No PCI buses available'

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 88, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/create.py", line 2288, in _do_async_install
    guest.start_install(meter=meter)
  File "/usr/share/virt-manager/virtinst/guest.py", line 461, in start_install
    doboot, transient)
  File "/usr/share/virt-manager/virtinst/guest.py", line 396, in _create_guest
    self.domain = self.conn.createXML(install_xml or final_xml, 0)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 3782, in createXML
    if ret is None:raise libvirtError('virDomainCreateXML() failed', conn=self)
libvirtError: XML error: No PCI buses available

Some discussion of this issue took place a while ago.

  https://www.redhat.com/archives/libvir-list/2016-May/msg00197.html

Revision history for this message
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in libvirt (Ubuntu):
status: New → Confirmed
Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

Hi Magnus,
I didn't see this bug before as it was "before my time", so I beg your pardon for the late reply.

IMHO mips in qemu is mostly socially accepted bit-rot.
This is the same issue as [1] an open bug unhandled issue at [2].

[1]: https://www.redhat.com/archives/libvirt-users/2017-March/msg00032.html
[2]: https://bugzilla.redhat.com/show_bug.cgi?id=1432101

Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

I don't know if needed after all that time, but the TL;DR is that by default libvirt does not add a pci-root.

You can get around just doing so on your own, add:
  <controller type='pci' index='0' model='pci-root'/>

Mips also supports no custom cpu and I'm not sure on your openvswitch, so I was replacing this.

You can define e.g. [1] just fine, and if I'd have a kernel to boot it might even work.
Yet OTOH don't expect too much from MIPS support in general.

[1]: http://paste.ubuntu.com/25924130/

Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

Workaround provided, and known upstream issue - for now incomplete on more input.
Might be considered if upstream changes something, but even then likely not as SRU.

Fortunately a workaround was provided, so no blocker.

Changed in libvirt (Ubuntu):
status: Confirmed → Incomplete
status: Incomplete → Won't Fix
Bug Watch Updater (bug-watch-updater)
Changed in libvirt:
importance: Unknown → Undecided
status: Unknown → Confirmed
Revision history for this message
Aurelien Jarno (aurel32) wrote : Re: [Bug 1561497] [NEW] XML error: No PCI buses available when defining MIPS VM

On 2017-11-09 14:50, Launchpad Bug Tracker wrote:
> You have been subscribed to a public bug by philmd (philmd):
>
> When trying to define a VM using mips64el architecture, I get the
> following error message from virsh:
>
> XML error: No PCI buses available
>
> Using virt-manager results in a similar error message.

Please see https://www.redhat.com/archives/libvir-list/2016-May/msg00197.html

If someone has time to write the corresponding tests as requested and
get this patch integrated, that would be great.

--
Aurelien Jarno GPG: 4096R/1DDD8C9B
<email address hidden> http://www.aurel32.net

Revision history for this message
In , hhan (hhan-redhat-bugs) wrote :

Hello Iran, could you reproduce it again?

Revision history for this message
Jonathan Race (chateaulav) wrote :

Issue still present when attempting to create MIPS guest via virt-manager, and adding additional environments with same issue (virt-install and openstack nova leveraging libvirt). Attempts were made across multiple paths still receiving same error message 'XML error: No PCI buses available' when trying to define a VM using mips64el architecture.

System Information:

Description: Ubuntu Focal Fossa
Release: 20.04.3 LTS
Linux version 5.4.0-88-generic (buildd@lgw01-amd64-008) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #99-Ubuntu SMP Thu Sep 23 17:29:00 UTC 2021 (Ubuntu 5.4.0-88.99-generic 5.4.140)

Binary Information:

/usr/sbin/libvirtd
libvirtd (libvirt) 6.0.0

XML and Trace Errors:

- virt-install attempt
### https://pastebin.com/nuPPieaw
Error Message: ERROR XML error: No PCI buses available

- virt-manager attempt
### https://pastebin.com/camUditW
Error Message: libvirt.libvirtError: XML error: No PCI buses available

- openstack attempt
### https://pastebin.com/3Tsj7Cxz
### https://pastebin.com/6VunTvpy
Error Message: libvirt.libvirtError: XML error: No PCI buses available

reference for original patch details: https://listman.redhat.com/archives/libvir-list/2016-May/msg00197.html

Revision history for this message
In , jrace (jrace-redhat-bugs) wrote :

Issue still present when attempting to create MIPS guest via virt-manager, and adding additional environments with same issue (virt-install and openstack nova leveraging libvirt). Attempts were made across multiple paths still receiving same error message 'XML error: No PCI buses available' when trying to define a VM using mips64el architecture.

System Information:

Description: Ubuntu Focal Fossa
Release: 20.04.3 LTS
Linux version 5.4.0-88-generic (buildd@lgw01-amd64-008) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #99-Ubuntu SMP Thu Sep 23 17:29:00 UTC 2021 (Ubuntu 5.4.0-88.99-generic 5.4.140)

Binary Information:

/usr/sbin/libvirtd
libvirtd (libvirt) 6.0.0

XML and Trace Errors:

- virt-install attempt
### https://pastebin.com/nuPPieaw
Error Message: ERROR XML error: No PCI buses available

- virt-manager attempt
### https://pastebin.com/camUditW
Error Message: libvirt.libvirtError: XML error: No PCI buses available

- openstack attempt
### https://pastebin.com/3Tsj7Cxz
### https://pastebin.com/6VunTvpy
Error Message: libvirt.libvirtError: XML error: No PCI buses available

reference for original patch details: https://listman.redhat.com/archives/libvir-list/2016-May/msg00197.html
reference for original ubuntu bug details: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1561497

Revision history for this message
In , smooney (smooney-redhat-bugs) wrote :

i am not familar with the mips emulation but just in case its useful I suspect this is related to the machine type
https://www.qemu.org/docs/master/system/target-mips.html
the default one i don't think support PCI devices so malta? might be required.

the Loongson-3 virtual platform might also be work trying
https://www.phoronix.com/scan.php?page=news_item&px=Loongson3-Linux-5.8-KVM-Virt
it sound like it a realitive recent platform.

https://listman.redhat.com/archives/libvir-list/2016-May/msg00197.html
which you reference before was related to the malta machine type.
so it seam to confirm it has a root PCIe controller so that is probably the best place to start.

Revision history for this message
In , jrace (jrace-redhat-bugs) wrote :
Download full text (4.3 KiB)

All associated mailing lists relating to this bug:

https://listman.redhat.com/archives/libvir-list/2016-May/msg00197.html
- associated code:

Signed-off-by: Aurelien Jarno <aurelien aurel32 net>
---
 src/qemu/qemu_domain.c | 15 ++++++++++++++-
 src/qemu/qemu_domain.h | 1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 173f82c..75b0545 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 173f82c..75b0545 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -1763,6 +1763,14 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
             addPCIeRoot = virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_GPEX);
         break;

+ case VIR_ARCH_MIPS:
+ case VIR_ARCH_MIPSEL:
+ case VIR_ARCH_MIPS64:
+ case VIR_ARCH_MIPS64EL:
+ if (qemuDomainMachineIsMalta(def))
+ addPCIRoot = true;
+ break;
+
     case VIR_ARCH_PPC64:
     case VIR_ARCH_PPC64LE:
         addPCIRoot = true;
@@ -4654,6 +4662,11 @@ qemuDomainMachineIsVirt(const virDomainDef *def)
            STRPREFIX(def->os.machine, "virt-");
 }

+bool
+qemuDomainMachineIsMalta(const virDomainDef *def)
+{
+ return STRPREFIX(def->os.machine, "malta");
+}

 static bool
 qemuCheckMemoryDimmConflict(const virDomainDef *def,
@@ -4830,7 +4843,7 @@ bool
 qemuDomainMachineHasBuiltinIDE(const virDomainDef *def)
 {
     return qemuDomainMachineIsI440FX(def) ||
- STREQ(def->os.machine, "malta") ||
+ qemuDomainMachineIsMalta(def) ||
         STREQ(def->os.machine, "sun4u") ||
         STREQ(def->os.machine, "g3beige");
 }
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 95f821c..adba5fa 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -585,6 +585,7 @@ bool qemuDomainMachineIsI440FX(const virDomainDef *def);
 bool qemuDomainMachineNeedsFDC(const virDomainDef *def);
 bool qemuDomainMachineIsS390CCW(const virDomainDef *def);
 bool qemuDomainMachineIsVirt(const virDomainDef *def);
+bool qemuDomainMachineIsMalta(const virDomainDef *def);
 bool qemuDomainMachineHasBuiltinIDE(const virDomainDef *def);

 int qemuDomainUpdateCurrentMemorySize(virQEMUDriverPtr driver,
--

https://www.spinics.net/linux/fedora/libvir/msg227695.html
- references general libvirt pci bus error

https://www.spinics.net/linux/fedora/libvir/msg227696.html
- associated code:

Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
---
 src/util/virarch.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/util/virarch.h b/src/util/virarch.h
index 528f84f8a5..81b1b27a57 100644
--- a/src/util/virarch.h
+++ b/src/util/virarch.h
@@ -95,6 +95,11 @@ typedef enum {
 #define ARCH_IS_S390(arch) ((arch) == VIR_ARCH_S390 ||\
                             (arch) == VIR_ARCH_S390X)

+#define ARCH_IS_MIPS(arch) ((arch) == VIR_ARCH_MIPS ||\
+ (arch) == VIR_ARCH_MIPSEL ||\
+ (arch) == VIR_ARCH_MIPS64 ||\
+ (arch) == VIR_ARCH_MIPS64EL)
+
 #define ARCH_IS_MIPS64(arch) ((arch) == VIR_ARCH_MIPS64 ||\
                               (a...

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