Hi,
this is not a show stopper at all.
It is just a warning and it is fine.
It is a trade-off between the "ease to use nested virt" vs "this warning".
For example on an intel chip you'd get:
qemu-system-x86_64: warning: host doesn't support requested feature:
CPUID.80000001H:ECX.svm
And that as well is no issue.
Since this is Ubuntu downstream decision to prefer simplicity for nested
virt I marked upstream qemu task invalid. There you'd not see the
warning, but instead would have to jump a few extra whoops to get
nesting working.
And finally, this code really is like that for longer than I take a look at it,
so it might be that today one could solve it differently. There could be much
more magic code to make it work as comfortable on both platforms and avoid the
warning, but honestly - it wasn't an issue for many years, and I think it still
is none.
So for the Ubuntu portion, I'll set confirmed+low(est) prio until it is clear
that this really breaks something it didn't in the past years.
** Changed in: qemu (Ubuntu)
Status: Incomplete => Confirmed
** Changed in: qemu (Ubuntu)
Importance: Undecided => Wishlist
** Changed in: qemu (Ubuntu)
Importance: Wishlist => Low
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https://bugs.launchpad.net/bugs/1722074
Title:
warning: host doesn't support requested feature: CPUID.01H:ECX.vmx
Status in QEMU:
Invalid
Status in qemu package in Ubuntu:
Confirmed
Bug description:
I encountered the bug today (when using qemu to boot up images - which used
to work on my Intel CPU box):
warning: host doesn't support requested feature: CPUID.01H:ECX.vmx
The bug is a show-stopper - I completely cannot load my kernel images
at all.
My Ubuntu have this version of QEMU installed:
qemu-system-x86_64 --version
QEMU emulator version 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.16),
Copyright (c) 2003-2008 Fabrice Bellard
And PC is a AMD Ryzen7 CPU built, and this is the first time I am
using it to load QEMU images. My host information:
cat /proc/cpuinfo |more
processor : 0
vendor_id : AuthenticAMD
cpu family : 23
model : 1
model name : AMD Ryzen 7 1700X Eight-Core Processor
stepping : 1
microcode : 0x800110e
cpu MHz : 2200.000
cache size : 512 KB
physical id : 0
siblings : 16
core id : 0
cpu cores : 8
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb
rdtscp
lm constant_tsc rep_good nopl nonstop_tsc extd_apicid aperfmperf pni
pclmulqdq
monitor ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand
lahf
_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch
osvw s
kinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_l2 mwaitx
hw_pstate
vmmcall fsgsbase bmi1 avx2 smep bmi2 rdseed adx smap clflushopt sha_ni
xsaveopt
xsavec xgetbv1 xsaves clzero irperf arat npt lbrv svm_lock nrip_save
tsc_scale v
mcb_clean flushbyasid decodeassists pausefilter pfthreshold avic
overflow_recov
succor smca
bugs : fxsave_leak sysret_ss_attrs null_seg
bogomips : 6787.24
TLB size : 2560 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm hwpstate eff_freq_ro [13] [14]
processor : 1
vendor_id : AuthenticAMD
cpu family : 23
model : 1
model name : AMD Ryzen 7 1700X Eight-Core Processor
stepping : 1
microcode : 0x800110e
cpu MHz : 2200.000
cache size : 512 KB
From other places, it can be seen that this is an AMD CPU issue:
https://www.virtualmin.com/node/52227
not sure?
The bug will also affect the host negatively: it will completely go
into a hung mode - the entire host becomes completely unsable.
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