On Tue, Sep 07, 2010 at 02:23:55PM +0200, Alexander Graf wrote:
>
> On 07.09.2010, at 13:27, Joerg Roedel wrote:
>
> > This patch changes the setting logic for the svm bit in
> > qemu-kvm. The bit is now explicitly set on -enable-nesting
> > instead of masked out if the parameter is not supplied.
> >
> > Signed-off-by: Joerg Roedel <joerg.roe...@amd.com>
> > ---
> > target-i386/cpuid.c | 12 ++++++------
> > 1 files changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/target-i386/cpuid.c b/target-i386/cpuid.c
> > index d63fdcb..5fa0dd0 100644
> > --- a/target-i386/cpuid.c
> > +++ b/target-i386/cpuid.c
> > @@ -276,8 +276,8 @@ static x86_def_t builtin_x86_defs[] = {
> > .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_CX16 | CPUID_EXT_POPCNT,
> > .ext2_features = (PPRO_FEATURES & EXT2_FEATURE_MASK) |
> > CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> > - .ext3_features = CPUID_EXT3_LAHF_LM | CPUID_EXT3_SVM |
> > - CPUID_EXT3_ABM | CPUID_EXT3_SSE4A,
> > + .ext3_features = CPUID_EXT3_LAHF_LM | CPUID_EXT3_ABM |
> > + CPUID_EXT3_SSE4A,
> > .xlevel = 0x8000000A,
> > .model_id = "QEMU Virtual CPU version " QEMU_VERSION,
> > },
> > @@ -303,8 +303,8 @@ static x86_def_t builtin_x86_defs[] = {
> > CPUID_EXT3_CR8LEG,
> > CPUID_EXT3_MISALIGNSSE, CPUID_EXT3_3DNOWPREFETCH,
> > CPUID_EXT3_OSVW, CPUID_EXT3_IBS */
> > - .ext3_features = CPUID_EXT3_LAHF_LM | CPUID_EXT3_SVM |
> > - CPUID_EXT3_ABM | CPUID_EXT3_SSE4A,
> > + .ext3_features = CPUID_EXT3_LAHF_LM | CPUID_EXT3_ABM |
> > + CPUID_EXT3_SSE4A,
> > .xlevel = 0x8000001A,
> > .model_id = "AMD Phenom(tm) 9550 Quad-Core Processor"
> > },
> > @@ -1154,8 +1154,8 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> > uint32_t count,
> > /* disable CPU features that KVM cannot support */
> >
> > /* svm */
> > - if (!kvm_nested)
> > - *ecx &= ~CPUID_EXT3_SVM;
> > + if (kvm_nested)
>
> I think we should get rid of kvm_nested and -enable-nesting. Instead, we
> should enable the SVM bit in the "host" and "qemu64" cpu types, but not in
> "kvm64". This way users are safe to not use nested svm, but can choose to do
> so if they like.
>
> Also, it should be possible to do something like -cpu kvm64,flags=+svm.
> Without having to mess with -enable-nesting.
I agree that its much nicer for mgmt tools if svm/vmx CPU flags can just be
toggled in the normal manner. Might we also want to have a enable/disable
nesting flag, so we can mirror the way real hardware lets you disable virt
in the BIOS even when the CPU(s) have the vmx/svm flags set ?
Regards,
Daniel
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