Re: [patch v2 3/8] KVM: x86: add Intel processor trace virtualization mode

[Paolo Bonzini]

On 30/10/2017 23:05, Luwei Kang wrote:
> +#define VM_EXIT_PT_SUPPRESS_PIP                      0x01000000
> +#define VM_EXIT_CLEAR_IA32_RTIT_CTL          0x02000000
>  
>  #define VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR    0x00036dff
>  
> @@ -108,6 +112,8 @@
>  #define VM_ENTRY_LOAD_IA32_PAT                       0x00004000
>  #define VM_ENTRY_LOAD_IA32_EFER                 0x00008000
>  #define VM_ENTRY_LOAD_BNDCFGS                   0x00010000
> +#define VM_ENTRY_PT_SUPPRESS_PIP             0x00020000
> +#define VM_ENTRY_LOAD_IA32_RTIT_CTL          0x00040000


Please use PT_CONCEAL instead of PT_SUPPRESS_PIP, to better match the
SDM (for both vmexit and vmentry controls).

> +     if (!enable_ept)
> +             vmexit_control &= ~VM_EXIT_CLEAR_IA32_RTIT_CTL;
> +

Why is this (and the similar bit-clear operation in vmx_vmentry_control)
needed only for !enable_ept?

Shouldn't it be like

        if (pt_mode == PT_MODE_SYSTEM) {
                vmexit_control &= ~VM_EXIT_PT_SUPPRESS_PIP;
                vmexit_control &= ~VM_EXIT_CLEAR_IA32_RTIT_CTL;
        }

and

        if (pt_mode == PT_MODE_SYSTEM) {
                vmentry_control &= ~VM_ENTRY_PT_SUPPRESS_PIP;
                vmentry_control &= ~VM_ENTRY_LOAD_IA32_RTIT_CTL;
        }

Thanks,

Paolo