linux-kernel - Re: [PATCH v3 18/25] KVM: VMX: Add missing CPU based VM execution controls to vmcs

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Date:   Tue, 12 Jul 2022 14:57:45 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     Anirudh Rayabharam <anrayabh@...ux.microsoft.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 18/25] KVM: VMX: Add missing CPU based VM execution
 controls to vmcs_config

On Fri, 2022-07-08 at 16:42 +0200, Vitaly Kuznetsov wrote:
> As a preparation to reusing the result of setup_vmcs_config() in
> nested VMX MSR setup, add the CPU based VM execution controls which KVM
> doesn't use but supports for nVMX to KVM_OPT_VMX_CPU_BASED_VM_EXEC_CONTROL
> and filter them out in vmx_exec_control().
> 
> No functional change intended.
> 
> Reviewed-by: Jim Mattson <jmattson@...gle.com>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> ---
>  arch/x86/kvm/vmx/vmx.c | 6 ++++++
>  arch/x86/kvm/vmx/vmx.h | 6 +++++-
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 2fb89bdcbbd8..9771c771c8f5 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -4240,6 +4240,12 @@ static u32 vmx_exec_control(struct vcpu_vmx *vmx)
>  {
>         u32 exec_control = vmcs_config.cpu_based_exec_ctrl;
>  
> +       /* Not used by KVM but supported for nesting. */
> +       exec_control &= ~(CPU_BASED_RDTSC_EXITING |
> +                         CPU_BASED_USE_IO_BITMAPS |
> +                         CPU_BASED_MONITOR_TRAP_FLAG |
> +                         CPU_BASED_PAUSE_EXITING);
> +
>         /* INTR_WINDOW_EXITING and NMI_WINDOW_EXITING are toggled dynamically */
>         exec_control &= ~(CPU_BASED_INTR_WINDOW_EXITING |
>                           CPU_BASED_NMI_WINDOW_EXITING);
> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
> index e9c392398f1b..758f80c41beb 100644
> --- a/arch/x86/kvm/vmx/vmx.h
> +++ b/arch/x86/kvm/vmx/vmx.h
> @@ -539,9 +539,13 @@ static inline u8 vmx_get_rvi(void)
>  #endif
>  
>  #define KVM_OPT_VMX_CPU_BASED_VM_EXEC_CONTROL                  \
> -       (CPU_BASED_TPR_SHADOW |                                 \
> +       (CPU_BASED_RDTSC_EXITING |                              \
> +       CPU_BASED_TPR_SHADOW |                                  \
> +       CPU_BASED_USE_IO_BITMAPS |                              \
> +       CPU_BASED_MONITOR_TRAP_FLAG |                           \
>         CPU_BASED_USE_MSR_BITMAPS |                             \
>         CPU_BASED_NMI_WINDOW_EXITING |                          \
> +       CPU_BASED_PAUSE_EXITING |                               \
>         CPU_BASED_ACTIVATE_SECONDARY_CONTROLS |                 \
>         CPU_BASED_ACTIVATE_TERTIARY_CONTROLS)
>  

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Best regards,
	Maxim Levitsky <mlevitsk@...hat.com>