linux-kernel - Re: [PATCH v8 049/103] KVM: VMX: Move setting of EPT MMU masks to common VT-x code

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Date:   Fri, 2 Sep 2022 15:23:33 +0800
From:   Yuan Yao <yuan.yao@...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>
Subject: Re: [PATCH v8 049/103] KVM: VMX: Move setting of EPT MMU masks to
 common VT-x code

On Sun, Aug 07, 2022 at 03:01:34PM -0700, isaku.yamahata@...el.com wrote:
> From: Sean Christopherson <sean.j.christopherson@...el.com>
>
> EPT MMU masks are used commonly for VMX and TDX.  The value needs to be
> initialized in common code before both VMX/TDX-specific initialization
> code.

The "VMX/TDX-specific initialization code" is not clear enough, the
patch moves the EPT MMU masks initialization AFTER
vmx_hardware_setup() and tdx_hardware_setup(), and these 2
hardware_setup functions are ahead of other VMX/TDX initializtion
code. I guess we can drop this patch ?

>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> ---
>  arch/x86/kvm/vmx/main.c | 5 +++++
>  arch/x86/kvm/vmx/vmx.c  | 4 ----
>  2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index ce12cc8276ef..9f4c3a0bcc12 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -4,6 +4,7 @@
>  #include "x86_ops.h"
>  #include "vmx.h"
>  #include "nested.h"
> +#include "mmu.h"
>  #include "pmu.h"
>  #include "tdx.h"
>
> @@ -26,6 +27,10 @@ static __init int vt_hardware_setup(void)
>
>  	enable_tdx = enable_tdx && !tdx_hardware_setup(&vt_x86_ops);
>
> +	if (enable_ept)
> +		kvm_mmu_set_ept_masks(enable_ept_ad_bits,
> +				      cpu_has_vmx_ept_execute_only());
> +
>  	return 0;
>  }
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 3af8cd164274..db33c2808e0e 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -8209,10 +8209,6 @@ __init int vmx_hardware_setup(void)
>
>  	set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
>
> -	if (enable_ept)
> -		kvm_mmu_set_ept_masks(enable_ept_ad_bits,
> -				      cpu_has_vmx_ept_execute_only());
> -
>  	/*
>  	 * Setup shadow_me_value/shadow_me_mask to include MKTME KeyID
>  	 * bits to shadow_zero_check.
> --
> 2.25.1
>