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DescriptionEduardo Habkost
2012-05-17 15:44:08 UTC
Cloning this for RHEL7, to make sure we fix it on RHEL7 too.
+++ This bug was initially created as a clone of Bug #692374 +++
Description of problem:
Version-Release number of selected component (if applicable):
# uname -r
2.6.32-128.el6.x86_64
# rpm -q qemu-kvm
qemu-kvm-0.12.1.2-2.153.el6.x86_64
How reproducible:
100%
Steps to Reproduce:
1.<commandline> -cpu Penryn,+ace,enforce ( ace is the flag on Westmere cpu model)
2.<commandLine> -cpu Conroe,+smx,enforce ( smx is the flag on Westmere cpu model)
3.<commandLine> -cpu Nehalem,+ace,enforce
Actual results:
QEMU runs in both cases
Expected results:
QEMU does not run
Additional info:
#<commandLine> -cpu host,+ace,enforce
CPU feature ace not found
warning: host cpuid 0000_0001:ecx flag restricted to guest 'vmx' [0x00000020]
Unable to support requested x86 CPU definition
#<commandLine> -cpu cpu64-rhel6,+ace,enforce
CPU feature ace not found
warning: host cpuid 8000_0001:ecx lacks requested flag 'svm' [0x00000004]
warning: host cpuid 8000_0001:ecx lacks requested flag 'abm' [0x00000020]
warning: host cpuid 8000_0001:ecx lacks requested flag 'sse4a' [0x00000040]
Unable to support requested x86 CPU definition
--- Additional comment from john.cooper on 2011-04-05 20:40:47 EDT ---
Yes that is the default "-cpu" flag parsing of qemu, namely it doesn't
bail if unknown flags are present:
# x86_64-softmmu/qemu-system-x86_64 -smp 1 -netic -net user ../../winxp-64.img \
-m 1024 -cpu Penryn,+popcnt,+ou812,+sse4_2,check
Using CPU model "Penryn,+popcnt,+ou812,+sse4_2,check"
CPU feature ou812 not found
warning: host cpuid 0000_0001:ecx lacks requested flag 'sse4.2|sse4_2' [0x00100000]
warning: host cpuid 0000_0001:ecx lacks requested flag 'popcnt' [0x00800000]
<guest launches>
But you're right "enforce" semantics should be held (in addition to
complaining) and qemu should error exit. It's a nit and should be
cleaned up the next time we're in that section of the code.
--- Additional comment from ehabkost on 2012-03-27 15:56:03 EDT ---
Not only non-existing flags are not rejected properly, but also flags that exist, are supported by the host, but unsupported by the kernel. e.g.:
-cpu Opteron_G3,+ht,-svm,enforce
HT is not supported by the KVM kernel module and gets disabled, but Qemu continues to run without aborting.
--- Additional comment from ehabkost on 2012-04-20 16:46:49 EDT ---
*** Bug 813132 has been marked as a duplicate of this bug. ***
Reproduce this bug using the following version:
kernel-3.7.0-0.36.el7.x86_64
qemu-kvm-1.3.0-6.el7.x86_64
On SandyBridge host, add the flags of Haswell to the guest
Steps to Reproduce:
1.<commandline> -cpu Penryn,+fma,enforce ( fma is the flag on Haswell cpu model)
2.<commandLine> -cpu Conroe,+hle,enforce ( hle is the flag on Haswell cpu model)
3.<commandLine> -cpu Nehalem,+avx2,enforce ( avx2 is the flag on Haswell cpu model)
Actual results:
After step1, 2, 3, the guest can boot and qemu-kvm is not quit.
Verify this bug using the following version:
kernel-3.10.0-67.el7.x86_64
qemu-kvm-1.5.3-38.el7.x86_64
Verification steps:
1.<commandline> -cpu Penryn,+fma,enforce ( fma is the flag on Haswell cpu model)
2.<commandLine> -cpu Conroe,+hle,enforce ( hle is the flag on Haswell cpu model)
3.<commandLine> -cpu Nehalem,+avx2,enforce ( avx2 is the flag on Haswell cpu model)
Actual results:
After step1, qemu-kvm quits with the info:
(qemu) warning: host doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
qemu-kvm: Host's CPU doesn't support requested features
After step2, qemu-kv quits with the info:
(qemu) warning: host doesn't support requested feature: CPUID.07H:EBX.hle [bit 4]
qemu-kvm: Host's CPU doesn't support requested features
After step3, qemu-kvm quits with the info:
(qemu) warning: host doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
qemu-kvm: Host's CPU doesn't support requested features
Hi, Eduardo,
I also test a non-existing flag like "aaa" using qemu-kvm-1.5.3-38.el7.x86_64
The steps is:
1.<commandline> -cpu Penryn,+aaa,enforce
The result is that qemu-kvm will not quit, guest can boot and qemu-kvm outputs the following info:
(qemu) CPU feature aaa not found
I think qemu-kvm should quit. If I'm wrong, please fix me. Thanks a lot.
Best regards
Huiqing
(In reply to huiqingding from comment #3)
> Hi, Eduardo,
>
> I also test a non-existing flag like "aaa" using qemu-kvm-1.5.3-38.el7.x86_64
>
> The steps is:
> 1.<commandline> -cpu Penryn,+aaa,enforce
>
> The result is that qemu-kvm will not quit, guest can boot and qemu-kvm
> outputs the following info:
> (qemu) CPU feature aaa not found
>
> I think qemu-kvm should quit. If I'm wrong, please fix me. Thanks a lot.
qemu-kvm should quit, but this doesn't affect libvirt because libvirt never does that (and we don't support running qemu-kvm directly). So I opened a new bug for that: bug 1055532.
This request was resolved in Red Hat Enterprise Linux 7.0.
Contact your manager or support representative in case you have further questions about the request.