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

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Date:	Tue, 9 Sep 2008 00:52:26 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Sheng Yang" <sheng.yang@...el.com>
Cc:	"Ingo Molnar" <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	"Avi Kivity" <avi@...ranet.com>, "Andi Kleen" <ak@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Thomas Gleixner" <tglx@...utronix.de>
Subject: Re: [PATCH 2/2] x86: Extended cpuinfo to show virtualization HW features

On Mon, Sep 8, 2008 at 11:54 PM, Sheng Yang <sheng.yang@...el.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@...el.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
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