Re: [PATCH 2/2] x86: Extended cpuinfo to show virtualization HW features

Yinghai Lu
2008-09-09T07:52:36Z

On Mon, Sep 8, 2008 at 11:54 PM, Sheng Yang <sheng.yang@intel.com> wrote:
> The hardware virtualization technology evolves very fast. But currently
> it's hard to tell if your CPU support a certain kind of HW technology
> without digging into the source code.
>
> The patch add a new catagory in "flags" under /proc/cpuinfo. Now "flags"
> can indicate the (important) HW virtulization features the CPU supported
> as well.
>
> Current implementation just cover Intel VMX side.
>
> Signed-off-by: Sheng Yang <sheng.yang@intel.com>
> ---
> arch/x86/kernel/cpu/common.c | 45 ++++++++++++++++++++++++++++++++++++++++++
> include/asm-x86/cpufeature.h | 9 +++++++-
> 2 files changed, 53 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index f7c1964..01432e2 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -581,6 +581,50 @@ static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
> }
> }
>
> +static void __cpuinit detect_vmx_virtcap(struct cpuinfo_x86 *c)
> +{
> + /* Intel VMX MSR indicated features */
> +#define X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW 0x00200000
> +#define X86_VMX_FEATURE_PROC_CTLS_VNMI 0x00400000
> +#define X86_VMX_FEATURE_PROC_CTLS_2ND_CTLS 0x80000000
> +#define X86_VMX_FEATURE_PROC_CTLS2_VIRT_APIC 0x00000001
> +#define X86_VMX_FEATURE_PROC_CTLS2_EPT 0x00000002
> +#define X86_VMX_FEATURE_PROC_CTLS2_VPID 0x00000020
> +
> + u32 vmx_msr_low, vmx_msr_high, msr_ctl, msr_ctl2;
> +
> + clear_cpu_cap(c, X86_FEATURE_TPR_SHADOW);
> + clear_cpu_cap(c, X86_FEATURE_VNMI);
> + clear_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
> + clear_cpu_cap(c, X86_FEATURE_EPT);
> + clear_cpu_cap(c, X86_FEATURE_VPID);
> +
> + rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, vmx_msr_low, vmx_msr_high);
> + msr_ctl = vmx_msr_high | vmx_msr_low;
> + if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW)
> + set_cpu_cap(c, X86_FEATURE_TPR_SHADOW);
> + if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_VNMI)
> + set_cpu_cap(c, X86_FEATURE_VNMI);
> + if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_2ND_CTLS) {
> + rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2,
> + vmx_msr_low, vmx_msr_high);
> + msr_ctl2 = vmx_msr_high | vmx_msr_low;
> + if ((msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VIRT_APIC) &&
> + (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW))
> + set_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
> + if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_EPT)
> + set_cpu_cap(c, X86_FEATURE_EPT);
> + if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VPID)
> + set_cpu_cap(c, X86_FEATURE_VPID);
> + }
> +}
> +
> +static void __cpuinit detect_virtcap(struct cpuinfo_x86 *c)
> +{
> + if (cpu_has(c, X86_FEATURE_VMX))
> + detect_vmx_virtcap(c);
> +}
> +
> static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
> {
> if (!have_cpuid_p())
> @@ -613,6 +657,7 @@ static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
>
> init_scattered_cpuid_features(c);
> detect_nopl(c);
> + detect_virtcap(c);

it should go into intel_64.c and intel.c

YH