Re: [Qemu-devel] Re: SVM support in 0.12?

[Andre Przywara]

Jun Koi wrote:
> > > > > > I am running latest Qemu 0.12-rc. My guest VM runs Linux kernel 2.6.31.
> > > > > >
> > > > > > Because Qemu now supports SVM, I expect to see the SVM flag in
> > > > > > /proc/cpuinfo, but that is not the case.
> > > > > >
> > > > > > So it seems SVM support is not enabled by default configuration??
> > > > > My host and guest are both 32 bit Linux, if that matters.
> > > > >
> > > > > (And this is pure Qemu, without using KVM or KQemu)
> > > > Kqemu actually works with svm emulation.
...
> > > qemu -m 500 -cpu qemu32,+svm -cdrom ubuntu.iso
> > >
> > > I verified that /proc/cpuinfo has no svm flag. So SVM doesnt work on 32bit
> > > host.
> > >
> > > I will try that with 64bit host to see how it goes.
> > The host doesn't matter. You can easily run qemu-system-x86_64 on a 32-bit
> > host.
>
> I can confirm that SVM works well on x86-64 target, but fails on i386 target.

The Linux kernel will only detect SVM if the machine is AMD (see 
linux-2.6/arch/x86/include/asm/virtext.h:cpu_has_svm())
So please try:
$ qemu -m 500 -cpu qemu32,+svm,vendor=AuthenticAMD -cdrom ubuntu.iso
(because the default vendor for qemu32 is Intel, for qemu64 AMD)

Regards,
Andre.

--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
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