[Qemu-devel] Is qemu (version 1.0) support to emulate the CPU feture "x2APIC"?

[Qemu-devel] Is qemu (version 1.0) support to emulate the CPU feture "x2APIC"?

[developer wang]

[-- Attachment #1: Type: text/plain, Size: 1520 bytes --]

Hi,

  I want to use qemu (version 1.0) to emulate guest systems with x2APIC enabled.

  But when I use qemu to emulate CPU's feture "x2APIC", I didn't find
it in /proc/cpuinfo.

  And I saw the source code of qemu.

  I only find a single define (#define CPUID_EXE_X2APIC   (1<<21) )

  but no other places use this this define.

  Does this mean qemu now doesn't support to emulate the CPU's feture
of "x2APIC"?



  Our host machine is running Debian 6, and the host system has x2APIC support.

  I use the following command to run qemu:

    qemu-system-x86_64 -nographic -cpu qemu64,+x2apic -serial
mon:/dev/tty -hda ~/debian6.qcow2

After the guest (also Debian 6) boots up, I can't see x2apic in /proc/cpuinfo.

Our host machine's CPU features:

    model name      : Intel(R) Xeon(R) CPU E7- 4850  @ 2.00GHz
    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 arch_perfmon pebs bts
rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64
monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2
x2apic popcnt aes lahf_lm ida arat dts tpr_shadow vnmi flexpriority
ept vpid

The CPU feature from the guest emulated by QEMU:

    model name      : QEMU Virtual CPU version 1.0,1
    flags           : fpu pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm up pni cx16
popcnt hypervisor lahf_lm svm abm sse4a

[-- Attachment #2: Type: text/html, Size: 1703 bytes --]

Re: [Qemu-devel] Is qemu (version 1.0) support to emulate the CPU feture "x2APIC"?

[Gleb Natapov]

On Wed, Mar 07, 2012 at 09:54:28PM +0800, developer wang wrote:
> Hi,
> 
>   I want to use qemu (version 1.0) to emulate guest systems with x2APIC enabled.
> 
>   But when I use qemu to emulate CPU's feture "x2APIC", I didn't find
> it in /proc/cpuinfo.
> 
x2apic is supported only if kvm is used and only with in kernel irqchip
emulation (which is still not default in qemu upstream IIRC). Try with
qemu-kvm.

>   And I saw the source code of qemu.
> 
>   I only find a single define (#define CPUID_EXE_X2APIC   (1<<21) )
> 
>   but no other places use this this define.
> 
>   Does this mean qemu now doesn't support to emulate the CPU's feture
> of "x2APIC"?
> 
> 
> 
>   Our host machine is running Debian 6, and the host system has x2APIC support.
> 
>   I use the following command to run qemu:
> 
>     qemu-system-x86_64 -nographic -cpu qemu64,+x2apic -serial
> mon:/dev/tty -hda ~/debian6.qcow2
> 
> After the guest (also Debian 6) boots up, I can't see x2apic in /proc/cpuinfo.
> 
> Our host machine's CPU features:
> 
>     model name      : Intel(R) Xeon(R) CPU E7- 4850  @ 2.00GHz
>     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 arch_perfmon pebs bts
> rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64
> monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2
> x2apic popcnt aes lahf_lm ida arat dts tpr_shadow vnmi flexpriority
> ept vpid
> 
> The CPU feature from the guest emulated by QEMU:
> 
>     model name      : QEMU Virtual CPU version 1.0,1
>     flags           : fpu pse tsc msr pae mce cx8 apic sep mtrr pge
> mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm up pni cx16
> popcnt hypervisor lahf_lm svm abm sse4a

--
			Gleb.