linux-kernel - Re: [PATCH v17 003/116] KVM: x86/vmx: Refactor KVM VMX module init/exit functions

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Date:   Tue, 5 Dec 2023 15:42:54 +0800
From:   Binbin Wu <binbin.wu@...ux.intel.com>
To:     isaku.yamahata@...el.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        isaku.yamahata@...il.com, Paolo Bonzini <pbonzini@...hat.com>,
        erdemaktas@...gle.com, Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Kai Huang <kai.huang@...el.com>,
        Zhi Wang <zhi.wang.linux@...il.com>, chen.bo@...el.com,
        hang.yuan@...el.com, tina.zhang@...el.com
Subject: Re: [PATCH v17 003/116] KVM: x86/vmx: Refactor KVM VMX module
 init/exit functions



On 11/7/2023 10:55 PM, isaku.yamahata@...el.com wrote:
> From: Isaku Yamahata <isaku.yamahata@...el.com>
>
> Currently, KVM VMX module initialization/exit functions are a single
> function each.  Refactor KVM VMX module initialization functions into KVM
> common part and VMX part so that TDX specific part can be added cleanly.
> Opportunistically refactor module exit function as well.
>
> The current module initialization flow is,
> 0.) Check if VMX is supported,
> 1.) hyper-v specific initialization,
> 2.) system-wide x86 specific and vendor specific initialization,
> 3.) Final VMX specific system-wide initialization,
> 4.) calculate the sizes of VMX kvm structure and VMX vcpu structure,
> 5.) report those sizes to the KVM common layer and KVM common
>      initialization
>
> Refactor the KVM VMX module initialization function into functions with a
> wrapper function to separate VMX logic in vmx.c from a file, main.c, common
> among VMX and TDX.  Introduce a wrapper function for vmx_init().
>
> The KVM architecture common layer allocates struct kvm with reported size
> for architecture-specific code.  The KVM VMX module defines its structure
> as struct vmx_kvm { struct kvm; VMX specific members;} and uses it as
> struct vmx kvm.  Similar for vcpu structure. TDX KVM patches will define
> TDX specific kvm and vcpu structures.
>
> The current module exit function is also a single function, a combination
> of VMX specific logic and common KVM logic.  Refactor it into VMX specific
> logic and KVM common logic.  This is just refactoring to keep the VMX
> specific logic in vmx.c from main.c.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> ---
>   arch/x86/kvm/vmx/main.c    | 50 +++++++++++++++++++++++++++++++++++
>   arch/x86/kvm/vmx/vmx.c     | 54 +++++---------------------------------
>   arch/x86/kvm/vmx/x86_ops.h | 13 ++++++++-
>   3 files changed, 68 insertions(+), 49 deletions(-)
>
[...]
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index 4af1b01aa9c0..c4e3ae971f94 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -6,11 +6,22 @@
>   
>   #include "x86.h"
>   
> -__init int vmx_hardware_setup(void);
> +#if IS_ENABLED(CONFIG_HYPERV)
> +__init void hv_init_evmcs(void);
> +void hv_reset_evmcs(void);
> +#else /* IS_ENABLED(CONFIG_HYPERV) */
> +static inline void hv_init_evmcs(void) {}

Does this one need "__init"?
Though it's empty, I checked exist kernel code, other empty static 
inline ones
add "__init" for init code.

> +static inline void hv_reset_evmcs(void) {}
> +#endif /* IS_ENABLED(CONFIG_HYPERV) */
> +
> +bool kvm_is_vmx_supported(void);
> +int __init vmx_init(void);
> +void vmx_exit(void);
>   
>   extern struct kvm_x86_ops vt_x86_ops __initdata;
>   extern struct kvm_x86_init_ops vt_init_ops __initdata;
>   
> +__init int vmx_hardware_setup(void);
>   void vmx_hardware_unsetup(void);
>   int vmx_check_processor_compat(void);
>   int vmx_hardware_enable(void);