linux-kernel - Re: [PATCH v13 004/113] KVM: TDX: Initialize logical processor when onlined

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Date:   Wed, 15 Mar 2023 09:57:34 +0000
From:   "Huang, Kai" <kai.huang@...el.com>
To:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Yamahata, Isaku" <isaku.yamahata@...el.com>
CC:     "zhi.wang.linux@...il.com" <zhi.wang.linux@...il.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "Shahar, Sagi" <sagis@...gle.com>,
        "Aktas, Erdem" <erdemaktas@...gle.com>,
        "isaku.yamahata@...il.com" <isaku.yamahata@...il.com>,
        "dmatlack@...gle.com" <dmatlack@...gle.com>,
        "Christopherson,, Sean" <seanjc@...gle.com>
Subject: Re: [PATCH v13 004/113] KVM: TDX: Initialize logical processor when
 onlined

On Sun, 2023-03-12 at 10:55 -0700, isaku.yamahata@...el.com wrote:
> From: Isaku Yamahata <isaku.yamahata@...el.com>
> 
> TDX requires to call a TDX initialization function per logical processor
> (LP) before the LP uses TDX.  When CPU is onlined, call the TDX LP
> initialization API when cpu is onlined.  
> 

Double "when CPU is onlined".

> If it failed refuse onlininig of
> the cpu for simplicity instead of TDX avoiding the LP.

Sorry cannot understand this sentence, particularly, the "instead ..." part.

> 
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> ---
>  arch/x86/kvm/vmx/main.c    | 15 ++++++++++++++-
>  arch/x86/kvm/vmx/tdx.c     |  5 +++++
>  arch/x86/kvm/vmx/x86_ops.h |  2 ++
>  3 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 5c9f5e00b3c4..d1c9c7f55050 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -9,6 +9,19 @@
>  static bool enable_tdx __ro_after_init;
>  module_param_named(tdx, enable_tdx, bool, 0444);
>  
> +static int vt_hardware_enable(void)
> +{
> +	int ret;
> +
> +	ret = vmx_hardware_enable();
> +	if (!ret && enable_tdx) {
> +		ret = tdx_hardware_enable();
> +		if (ret)
> +			vmx_hardware_disable();
> +	}
> +	return ret;
> +}
> +
>  static __init int vt_hardware_setup(void)
>  {
>  	int ret;
> @@ -40,7 +53,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
>  
>  	.hardware_unsetup = vmx_hardware_unsetup,
>  
> -	.hardware_enable = vmx_hardware_enable,
> +	.hardware_enable = vt_hardware_enable,
>  	.hardware_disable = vmx_hardware_disable,
>  	.has_emulated_msr = vmx_has_emulated_msr,
>  
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index f3eb0138b60b..e51314bbb439 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -10,6 +10,11 @@
>  #undef pr_fmt
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
> +int tdx_hardware_enable(void)
> +{
> +	return tdx_cpu_enable();
> +}
> +
>  static int __init tdx_module_setup(void)
>  {
>  	int ret;
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index 0f200aead411..010d02c86ba4 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -139,8 +139,10 @@ void vmx_setup_mce(struct kvm_vcpu *vcpu);
>  
>  #ifdef CONFIG_INTEL_TDX_HOST
>  int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops);
> +int tdx_hardware_enable(void);
>  #else
>  static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -ENOSYS; }
> +static inline int tdx_hardware_enable(void) { return -EOPNOTSUPP; }
>  #endif
>  
>  #endif /* __KVM_X86_VMX_X86_OPS_H */