Bug 1128552

Summary:	RFC: delete rdtscp flag from -cpu ? dump
Product:	Red Hat Enterprise Linux 6	Reporter:	Jun Li <juli>
Component:	qemu-kvm	Assignee:	Eduardo Habkost <ehabkost>
Status:	CLOSED NOTABUG	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	low	Docs Contact:
Priority:	medium
Version:	6.6	CC:	acathrow, bsarathy, chayang, juzhang, michen, mkenneth, qzhang, virt-maint, xfu
Target Milestone:	rc
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2014-08-14 19:00:10 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Jun Li 2014-08-11 05:22:50 UTC

Description of problem:
As can not deliver rdtscp flag from host to guest, so should delete this rdtscp flag from -cpu ? dump.
Do not deliver rdtscp flag to guest for RHEL-6 kernel, ref: https://bugzilla.redhat.com/show_bug.cgi?id=814426#c5.

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.434.el6.x86_64
2.6.32-495.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1.dump -cpu ?.
# /usr/libexec/qemu-kvm -cpu ?

2.
3.

Actual results:
# /usr/libexec/qemu-kvm -cpu ?
x86       Opteron_G5  AMD Opteron 63xx class CPU                      
x86       Opteron_G4  AMD Opteron 62xx class CPU                      
x86       Opteron_G3  AMD Opteron 23xx (Gen 3 Class Opteron)          
x86       Opteron_G2  AMD Opteron 22xx (Gen 2 Class Opteron)          
x86       Opteron_G1  AMD Opteron 240 (Gen 1 Class Opteron)           
x86        Broadwell  Intel Core Processor (Broadwell)                
x86          Haswell  Intel Core Processor (Haswell)                  
x86      SandyBridge  Intel Xeon E312xx (Sandy Bridge)                
x86         Westmere  Westmere E56xx/L56xx/X56xx (Nehalem-C)          
x86          Nehalem  Intel Core i7 9xx (Nehalem Class Core i7)       
x86           Penryn  Intel Core 2 Duo P9xxx (Penryn Class Core 2)    
x86           Conroe  Intel Celeron_4x0 (Conroe/Merom Class Core 2)   
x86      cpu64-rhel5  QEMU Virtual CPU version (cpu64-rhel5)          
x86      cpu64-rhel6  QEMU Virtual CPU version (cpu64-rhel6)          
x86             n270  Intel(R) Atom(TM) CPU N270   @ 1.60GHz          
x86           athlon  QEMU Virtual CPU version 0.12.1                 
x86         pentium3                                                  
x86         pentium2                                                  
x86          pentium                                                  
x86              486                                                  
x86          coreduo  Genuine Intel(R) CPU           T2600  @ 2.16GHz 
x86           qemu32  QEMU Virtual CPU version 0.12.1                 
x86            kvm64  Common KVM processor                            
x86         core2duo  Intel(R) Core(TM)2 Duo CPU     T7700  @ 2.40GHz 
x86           phenom  AMD Phenom(tm) 9550 Quad-Core Processor         
x86           qemu64  QEMU Virtual CPU version 0.12.1                 

Recognized CPUID flags:
  f_edx: pbe ia64 tm ht ss sse2 sse fxsr mmx acpi ds clflush pn pse36 pat cmov mca pge mtrr sep apic cx8 mce pae msr tsc pse de vme fpu
  f_ecx: hypervisor rdrand f16c avx osxsave xsave aes tsc-deadline popcnt movbe x2apic sse4.2|sse4_2 sse4.1|sse4_1 dca pcid pdcm xtpr cx16 fma cid ssse3 tm2 est smx vmx ds_cpl monitor dtes64 pclmulqdq|pclmuldq pni|sse3
  extf_edx: 3dnow 3dnowext lm|i64 rdtscp pdpe1gb fxsr_opt|ffxsr fxsr mmx mmxext nx|xd pse36 pat cmov mca pge mtrr syscall apic cx8 mce pae msr tsc pse de vme fpu
  extf_ecx: perfctr_nb perfctr_core topoext tbm nodeid_msr tce fma4 lwp wdt skinit xop ibs osvw 3dnowprefetch misalignsse sse4a abm cr8legacy extapic svm cmp_legacy lahf_lm

Expected results:
Delete rdtscp flag from "qemu-kvm -cpu ?" dump, as this flag does not deliver to guest.

Additional info:

Comment 2 Eduardo Habkost 2014-08-14 19:00:10 UTC

"-cpu ?' is not a mechanism to check which features are supported by the host kernel. It only means that QEMU recognizes the feature name, it does not mean the host kernel supports it.