Bug 1128552 - RFC: delete rdtscp flag from -cpu ? dump
Summary: RFC: delete rdtscp flag from -cpu ? dump
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.6
Hardware: x86_64
OS: Linux
Target Milestone: rc
: ---
Assignee: Eduardo Habkost
QA Contact: Virtualization Bugs
Depends On:
TreeView+ depends on / blocked
Reported: 2014-08-11 05:22 UTC by Jun Li
Modified: 2014-08-14 19:00 UTC (History)
9 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2014-08-14 19:00:10 UTC

Attachments (Terms of Use)

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):

How reproducible:

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


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.

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