Re: [PATCH v18 007/121] KVM: VMX: Reorder vmx initialization with kvm vendor initialization

[Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>]

On 1/23/2024 7:52 AM, isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> To match vmx_exit cleanup.
Do you mean vt_exit()?
Shouldn't vt_init() and vt_exit() be symmetric right from the beginning in
the refactor patch (006/121)?

And also, since the reorder of kvm_x86_vendor_init() and vmx_init() is going
to happen, can we just skip moving around the init of loaded_vmcss_on_cpu?


> Now vmx_init() is before kvm_x86_vendor_init(),
> vmx_init() can initialize loaded_vmcss_on_cpu.  Oppertunistically move it
> back into vmx_init().
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
> v18:
> - move the loaded_vmcss_on_cpu initialization to vmx_init().
> - fix error path of vt_init(). by Chao and Binbin
> ---
>   arch/x86/kvm/vmx/main.c    | 17 +++++++----------
>   arch/x86/kvm/vmx/vmx.c     |  6 ++++--
>   arch/x86/kvm/vmx/x86_ops.h |  2 --
>   3 files changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 18cecf12c7c8..443db8ec5cd5 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -171,7 +171,7 @@ struct kvm_x86_init_ops vt_init_ops __initdata = {
>   static int __init vt_init(void)
>   {
>   	unsigned int vcpu_size, vcpu_align;
> -	int cpu, r;
> +	int r;
>   
>   	if (!kvm_is_vmx_supported())
>   		return -EOPNOTSUPP;
> @@ -182,18 +182,14 @@ static int __init vt_init(void)
>   	 */
>   	hv_init_evmcs();
>   
> -	/* vmx_hardware_disable() accesses loaded_vmcss_on_cpu. */
> -	for_each_possible_cpu(cpu)
> -		INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu));
> -
> -	r = kvm_x86_vendor_init(&vt_init_ops);
> -	if (r)
> -		return r;
> -
>   	r = vmx_init();
>   	if (r)
>   		goto err_vmx_init;
>   
> +	r = kvm_x86_vendor_init(&vt_init_ops);
> +	if (r)
> +		goto err_vendor_init;
> +
>   	/*
>   	 * Common KVM initialization _must_ come last, after this, /dev/kvm is
>   	 * exposed to userspace!
> @@ -207,9 +203,10 @@ static int __init vt_init(void)
>   	return 0;
>   
>   err_kvm_init:
> +	kvm_x86_vendor_exit();
> +err_vendor_init:
>   	vmx_exit();
>   err_vmx_init:
> -	kvm_x86_vendor_exit();
>   	return r;
>   }
>   module_init(vt_init);
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 8efb956591d5..3f4dad3acb13 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -477,7 +477,7 @@ DEFINE_PER_CPU(struct vmcs *, current_vmcs);
>    * We maintain a per-CPU linked-list of VMCS loaded on that CPU. This is needed
>    * when a CPU is brought down, and we need to VMCLEAR all VMCSs loaded on it.
>    */
> -DEFINE_PER_CPU(struct list_head, loaded_vmcss_on_cpu);
> +static DEFINE_PER_CPU(struct list_head, loaded_vmcss_on_cpu);
>   
>   static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);
>   static DEFINE_SPINLOCK(vmx_vpid_lock);
> @@ -8528,8 +8528,10 @@ int __init vmx_init(void)
>   	if (r)
>   		return r;
>   
> -	for_each_possible_cpu(cpu)
> +	for_each_possible_cpu(cpu) {
> +		INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu));
>   		pi_init_cpu(cpu);
> +	}
>   
>   	cpu_emergency_register_virt_callback(vmx_emergency_disable);
>   
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index b936388853ab..bca2d27b3dfd 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -14,8 +14,6 @@ static inline __init void hv_init_evmcs(void) {}
>   static inline void hv_reset_evmcs(void) {}
>   #endif /* IS_ENABLED(CONFIG_HYPERV) */
>   
> -DECLARE_PER_CPU(struct list_head, loaded_vmcss_on_cpu);
> -
>   bool kvm_is_vmx_supported(void);
>   int __init vmx_init(void);
>   void vmx_exit(void);