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Bug 1860743 - qemu promote host does not support MSR(10AH).taa-no [bit 8] on cooperlake machine
Summary: qemu promote host does not support MSR(10AH).taa-no [bit 8] on cooperlake mac...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: qemu-kvm
Version: 8.3
Hardware: x86_64
OS: Linux
high
high
Target Milestone: rc
: 8.0
Assignee: Eduardo Habkost
QA Contact: liunana
Jiri Herrmann
URL:
Whiteboard:
Depends On:
Blocks: 1897024
TreeView+ depends on / blocked
 
Reported: 2020-07-27 04:18 UTC by liunana
Modified: 2021-12-07 23:04 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Known Issue
Doc Text:
.Virtual machines using `Cooperlake` cannot boot when `TSX` is disabled on the host Virtual machines (VMs) that use the `Cooperlake` CPU model currently fail to boot when the `TSX` CPU flag is diabled on the host. Instead, the host displays the following error message: ---- the CPU is incompatible with host CPU: Host CPU does not provide required features: hle, rtm ---- To make VMs with `Cooperlake` usable on such host, disable the HLE, RTM, and TAA_NO flags in the VM configuration in the VM's XML configuration: ---- <feature policy='disable' name='hle'/> <feature policy='disable' name='rtm'/> <feature policy='disable' name='taa-no'/> ----
Clone Of:
Environment:
Last Closed: 2021-04-12 19:49:24 UTC
Type: Feature Request
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description liunana 2020-07-27 04:18:07 UTC 
Description of problem:
qemu promote host does not support  requested feature: MSR(10AH).taa-no [bit 8] on cooperlake machine


Version-Release number of selected component (if applicable):
Host
    kernel-4.18.0-227.el8.x86_64
    (old qemu) qemu-kvm-4.2.0-25.module+el8.3.0+6986+29a4dcd7
    (new qemu) qemu-kvm-4.2.0-31.module+el8.3.0+7437+4bb96e0d
    seabios-1.13.0-2.module+el8.3.0+7353+9de0a3cc.x86_64
    

How reproducible:
100%


Steps to Reproduce:
1.
# /usr/libexec/qemu-kvm -M q35 -cpu Cooperlake,enforce
qemu-kvm: warning: host doesn't support requested feature: CPUID.07H:EBX.hle [bit 4]
qemu-kvm: warning: host doesn't support requested feature: CPUID.07H:EBX.rtm [bit 11]
qemu-kvm: warning: host doesn't support requested feature: MSR(10AH).taa-no [bit 8]
qemu-kvm: Host doesn't support requested features



Actual results:
qemu can't boot with warning message.


Expected results:
qemu can boot without error.


Additional info:

Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              144
On-line CPU(s) list: 0-143
Thread(s) per core:  2
Core(s) per socket:  18
Socket(s):           4
NUMA node(s):        4
Vendor ID:           GenuineIntel
CPU family:          6
Model:               85
Model name:          Intel(R) Xeon(R) Platinum 8353H CPU @ 2.50GHz
Stepping:            11
CPU MHz:             2653.393
CPU max MHz:         3800.0000
CPU min MHz:         1000.0000
BogoMIPS:            5000.00
Virtualization:      VT-x
L1d cache:           32K
L1i cache:           32K
L2 cache:            1024K
L3 cache:            25344K
NUMA node0 CPU(s):   0-17,72-89
NUMA node1 CPU(s):   18-35,90-107
NUMA node2 CPU(s):   36-53,108-125
NUMA node3 CPU(s):   54-71,126-143
Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single intel_ppin ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local avx512_bf16 dtherm ida arat pln pts hwp hwp_act_window hwp_epp hwp_pkg_req pku ospke avx512_vnni md_clear flush_l1d arch_capabilities
Comment 3 John Ferlan 2020-08-04 20:39:14 UTC 
Assigned to Amnon for initial triage per bz process and age of bug created or assigned to virt-maint without triage
Comment 9 Eduardo Habkost 2020-08-25 13:49:33 UTC 
Can you clarify why this is a regression?  If the CPU model already includes TSX and the host disables TSX by default now, there's not much we can do.  We can't change the existing CPU model because it would break guest ABI.

Can you check what's the result of CPU model='host-model' on that host?  We won't change the CPU model in QEMU, but we do want to make sure libvirt makes it easy to deal with the removed feature.
Comment 10 liunana 2020-08-31 05:46:38 UTC 
(In reply to Eduardo Habkost from comment #9)

Hi, I just get the Cooperlake-Server machine.

> Can you clarify why this is a regression?  If the CPU model already includes
> TSX and the host disables TSX by default now, there's not much we can do. 
> We can't change the existing CPU model because it would break guest ABI.
> 

I have no problem with TSX.
And for "taa-no" since we have planed to disable it just like TSX I think we can remove the Regression word.Thanks.
 
> Can you check what's the result of CPU model='host-model' on that host?  We
> won't change the CPU model in QEMU, but we do want to make sure libvirt
> makes it easy to deal with the removed feature.

For CPU model='host-model' in xml, libvirt disables the flag hle, rtm, taa-no.

  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Cooperlake</model>
    <vendor>Intel</vendor>
    <feature policy='require' name='ss'/>
    <feature policy='require' name='vmx'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='tsc_adjust'/>
    <feature policy='require' name='mpx'/>
    <feature policy='require' name='umip'/>
    <feature policy='require' name='md-clear'/>
    <feature policy='require' name='xsaves'/>
    <feature policy='require' name='ibpb'/>
    <feature policy='require' name='amd-ssbd'/>
    <feature policy='disable' name='hle'/>
    <feature policy='disable' name='rtm'/>
    <feature policy='disable' name='taa-no'/>
  </cpu>

Test environments:
    intel-cedarisland-01.khw1.lab.eng.bos.redhat.com
    qemu-kvm-4.2.0-33.module+el8.3.0+7705+f09d73e4.x86_64
    kernel-4.18.0-234.el8.x86_64


And I will disable the "taa-no" manually with "-cpu Cooperlake,-taa-no,-hle,-rtm,enforce" as Doc Text said to use Cooperlake-Server cpu model now, thanks.



Best regards
Liu Nana
Comment 16 Eduardo Habkost 2021-04-12 19:49:24 UTC 
Just found this old BZ on my BZ list.

(In reply to liunana from comment #10)
> For CPU model='host-model' in xml, libvirt disables the flag hle, rtm,
> taa-no.
> 
>   <cpu mode='custom' match='exact' check='full'>
>     <model fallback='forbid'>Cooperlake</model>
>     <vendor>Intel</vendor>
>     <feature policy='require' name='ss'/>
>     <feature policy='require' name='vmx'/>
>     <feature policy='require' name='hypervisor'/>
>     <feature policy='require' name='tsc_adjust'/>
>     <feature policy='require' name='mpx'/>
>     <feature policy='require' name='umip'/>
>     <feature policy='require' name='md-clear'/>
>     <feature policy='require' name='xsaves'/>
>     <feature policy='require' name='ibpb'/>
>     <feature policy='require' name='amd-ssbd'/>
>     <feature policy='disable' name='hle'/>
>     <feature policy='disable' name='rtm'/>
>     <feature policy='disable' name='taa-no'/>
>   </cpu>
> 
> Test environments:
>     intel-cedarisland-01.khw1.lab.eng.bos.redhat.com
>     qemu-kvm-4.2.0-33.module+el8.3.0+7705+f09d73e4.x86_64
>     kernel-4.18.0-234.el8.x86_64
> 
> 
> And I will disable the "taa-no" manually with "-cpu
> Cooperlake,-taa-no,-hle,-rtm,enforce" as Doc Text said to use
> Cooperlake-Server cpu model now, thanks.

As libvirt does the right thing when TSX is disabled by the OS vendor or system administrator, closing this as NOTABUG.

See also:
https://lore.kernel.org/qemu-devel/20200825140145.GU642093@habkost.net/
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