Re: [PATCH] x86/Centaur: show more HW features in /proc/cpuinfo

From: Thomas Gleixner
Date: Tue Apr 17 2018 - 06:19:40 EST


On Sun, 8 Apr 2018, David Wang wrote:

> We add this patch to show correct HW features(arch_perfmon, tpr_shadow,
> vnmi, flexpriority, ept and vpid) when user execute "cat /proc/cpuinfo".

See the other mail vs. the changelog.

>
> Signed-off-by: David Wang <davidwang@xxxxxxxxxxx>
> ---
> arch/x86/kernel/cpu/centaur.c | 49 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c
> index e5ec0f1..969fb8f 100644
> --- a/arch/x86/kernel/cpu/centaur.c
> +++ b/arch/x86/kernel/cpu/centaur.c
> @@ -112,6 +112,44 @@ static void early_init_centaur(struct cpuinfo_x86 *c)
> }
> }
>
> +static void centaur_detect_vmx_virtcap(struct cpuinfo_x86 *c)
> +{
> +#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

Please move the defines outside the function. This is horrible to read,

> +
> + 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);

Why are you clearing the capabilities? They are cleared at boot time.

> + 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 init_centaur(struct cpuinfo_x86 *c)
> {
> #ifdef CONFIG_X86_32
> @@ -128,6 +166,14 @@ static void init_centaur(struct cpuinfo_x86 *c)
> clear_cpu_cap(c, 0*32+31);
> #endif
> early_init_centaur(c);
> +
> + if (c->cpuid_level > 9) {
> + unsigned eax = cpuid_eax(10);

Missing newline between variable declaration and code. checkpatch.pl should
have told you that.

> + /* Check for version and the number of counters */
> + if ((eax & 0xff) && (((eax >> 8) & 0xff) > 1))

Magic constants and a comment which does not explain how the check works.

> + set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);

Thanks,

tglx