I know, this is such an old topic ...
I have today upgraded my hypervisor from intel Ivy-Bridge to AMD Epyc Milan
and, after making the necessary adjustments in vfio configuration to make my
virtual machines work again, I found that there's immense amount of crackling
(like, many times per second) in audio, both in Linux and in Windows guests.
The audio is USB DAC connected through USB, and USB is on passed-through PCI
(dedicated for guest).
The host has two AMD 7413 CPUs, with lots of cores dedicated to guests:
video=efifb:off iommu=pt amd_iommu=on add_efi_memmap nohz_full=6-35,54-83
rcu_nocbs=6-35,54-83 isolcpus=6-35,54-83 nvme.poll_queues=12
Example guest:
<vcpu placement='static'>12</vcpu>
<iothreads>1</iothreads>
<cputune>
<vcpupin vcpu='0' cpuset='6'/>
<vcpupin vcpu='1' cpuset='54'/>
<vcpupin vcpu='2' cpuset='7'/>
<vcpupin vcpu='3' cpuset='55'/>
<vcpupin vcpu='4' cpuset='8'/>
<vcpupin vcpu='5' cpuset='56'/>
<vcpupin vcpu='6' cpuset='9'/>
<vcpupin vcpu='7' cpuset='57'/>
<vcpupin vcpu='8' cpuset='10'/>
<vcpupin vcpu='9' cpuset='58'/>
<vcpupin vcpu='10' cpuset='11'/>
<vcpupin vcpu='11' cpuset='59'/>
<emulatorpin cpuset='22-23,70-71'/>
<iothreadpin iothread='1' cpuset='21,69'/>
</cputune>
<numatune>
<memory mode='strict' nodeset='0'/>
</numatune>
<resource>
<partition>/machine</partition>
</resource>
<os>
<type arch='x86_64' machine='pc-q35-5.1'>hvm</type>
<loader readonly='yes'
type='pflash'>/usr/share/ovmf/x64/OVMF_CODE.fd</loader>
<nvram
template='/usr/share/ovmf/x64/OVMF_VARS.fd'>/var/lib/libvirt/qemu/nvram/lipowa_VARS.fd</nvram>
</os>
<features>
<acpi/>
<apic/>
<pae/>
<hyperv mode='custom'>
<relaxed state='on'/>
<vapic state='on'/>
<spinlocks state='on' retries='4096'/>
</hyperv>
</features>
<cpu mode='host-model' check='none'>
<topology sockets='1' dies='1' cores='6' threads='2'/>
</cpu>
<clock offset='utc'>
<timer name='rtc' tickpolicy='catchup' track='wall'/>
<timer name='pit' tickpolicy='delay'/>
<timer name='hpet' present='no'/>
<timer name='tsc' present='yes' mode='native'/>
<timer name='kvmclock' present='yes'/>
<timer name='hypervclock' present='yes'/>
</clock>
.
.
.
<controller type='sata' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1f'
function='0x2'/>
</controller>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='1' port='0x10'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'
multifunction='on'/>
</controller>
<controller type='pci' index='2' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='2' port='0x11'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x1'/>
</controller>
<controller type='pci' index='3' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='3' port='0x12'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x2'/>
</controller>
<controller type='pci' index='4' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='4' port='0x13'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x3'/>
</controller>
<controller type='pci' index='5' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='5' port='0x14'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x4'/>
</controller>
<controller type='pci' index='6' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='6' port='0x15'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x5'/>
</controller>
<controller type='pci' index='7' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='7' port='0x16'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x6'/>
</controller>
<controller type='pci' index='8' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='8' port='0x17'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x7'/>
</controller>
<controller type='scsi' index='0' model='virtio-scsi'>
<driver queues='12' iothread='1'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00'
function='0x0'/>
</controller>
<controller type='virtio-serial' index='0'>
<address type='pci' domain='0x0000' bus='0x02' slot='0x00'
function='0x0'/>
</controller>
<controller type='usb' index='0' model='qemu-xhci' ports='15'>
<address type='pci' domain='0x0000' bus='0x03' slot='0x00'
function='0x0'/>
</controller>
.
.
.
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x62' slot='0x00' function='0x0'/>
</source>
<rom bar='off'/>
<address type='pci' domain='0x0000' bus='0x05' slot='0x00'
function='0x0'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x41' slot='0x00' function='0x0'/>
</source>
<rom bar='off'/>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'
multifunction='on'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x41' slot='0x00' function='0x1'/>
</source>
<rom bar='off'/>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00'
function='0x1'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x41' slot='0x00' function='0x2'/>
</source>
<rom bar='off'/>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00'
function='0x2'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x41' slot='0x00' function='0x3'/>
</source>
<rom bar='off'/>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00'
function='0x3'/>
</hostdev>
<memballoon model='virtio'>
<address type='pci' domain='0x0000' bus='0x07' slot='0x00'
function='0x0'/>
</memballoon>
<rng model='virtio'>
<rate bytes='1048576'/>
<backend model='random'>/dev/urandom</backend>
<address type='pci' domain='0x0000' bus='0x08' slot='0x00'
function='0x0'/>
</rng>
</devices>
Sound is passed through USB card, which is dedicated to guest. From guest this
card looks like this:
05:00.0 USB controller [0c03]: Renesas Technology Corp. uPD720201 USB 3.0 Host
Controller [1912:0014] (rev 03) (prog-if 30 [XHCI])
Physical Slot: 0-4
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 22
Region 0: Memory at c1600000 (64-bit, non-prefetchable) [size=8K]
Capabilities: [50] Power Management version 3
Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA
PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [70] MSI: Enable- Count=1/8 Maskable- 64bit+
Address: 0000000000000000 Data: 0000
Capabilities: [90] MSI-X: Enable+ Count=8 Masked-
Vector table: BAR=0 offset=00001000
PBA: BAR=0 offset=00001080
Capabilities: [a0] Express (v2) Endpoint, MSI 00
DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s
unlimited, L1 unlimited
ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
SlotPowerLimit 0.000W
DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq-
RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+
MaxPayload 128 bytes, MaxReadReq 512 bytes
DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+
TransPend-
LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM L0s L1, Exit
Latency L0s <4us, L1 unlimited
ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp-
LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 5GT/s (ok), Width x1 (ok)
TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
DevCap2: Completion Timeout: Not Supported, TimeoutDis+,
NROPrPrP-, LTR+
10BitTagComp-, 10BitTagReq-, OBFF Not Supported,
ExtFmt-, EETLPPrefix-
EmergencyPowerReduction Not Supported,
EmergencyPowerReductionInit-
FRS-, TPHComp-, ExtTPHComp-
AtomicOpsCap: 32bit- 64bit- 128bitCAS-
DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+,
OBFF Disabled
AtomicOpsCtl: ReqEn-
LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
Transmit Margin: Normal Operating Range,
EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -3.5dB,
EqualizationComplete-, EqualizationPhase1-
EqualizationPhase2-, EqualizationPhase3-,
LinkEqualizationRequest-
Capabilities: [100 v1] Advanced Error Reporting
UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt-
RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt-
RxOF- MalfTLP- ECRC- UnsupReq+ ACSViol-
UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO+ CmpltAbrt- UnxCmplt+
RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout-
AdvNonFatalErr-
CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout-
AdvNonFatalErr-
AERCap: First Error Pointer: 00, ECRCGenCap- ECRCGenEn-
ECRCChkCap- ECRCChkEn-
MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
HeaderLog: 00000000 00000000 00000000 00000000
Capabilities: [150 v1] Latency Tolerance Reporting
Max snoop latency: 1048576ns
Max no snoop latency: 1048576ns
Kernel driver in use: xhci_hcd
Any ideas?
B.
--
Bronek Kozicki
b...@incorrekt.com
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