linux-kernel - Re: [PATCH v8 09/10] KVM: VMX: Open code VMX preemption timer rate mask in its accessor

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Message-ID: <2760e892-0a06-4790-9d5e-bba690dbdf91@intel.com>
Date: Wed, 12 Jun 2024 09:54:08 +0800
From: Xiaoyao Li <xiaoyao.li@...el.com>
To: Sean Christopherson <seanjc@...gle.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 x86@...nel.org, Paolo Bonzini <pbonzini@...hat.com>,
 Andy Lutomirski <luto@...nel.org>, Peter Zijlstra <peterz@...radead.org>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
 Kai Huang <kai.huang@...el.com>, Jim Mattson <jmattson@...gle.com>,
 Shan Kang <shan.kang@...el.com>, Xin Li <xin3.li@...el.com>,
 Zhao Liu <zhao1.liu@...el.com>
Subject: Re: [PATCH v8 09/10] KVM: VMX: Open code VMX preemption timer rate
 mask in its accessor

On 6/6/2024 7:19 AM, Sean Christopherson wrote:
> From: Xin Li <xin3.li@...el.com>
> 
> Use vmx_misc_preemption_timer_rate() to get the rate in hardware_setup(),
> and open code the rate's bitmask in vmx_misc_preemption_timer_rate() so
> that the function looks like all the helpers that grab values from
> VMX_BASIC and VMX_MISC MSR values.
> 
> No functional change intended.
> 
> Cc: Shan Kang <shan.kang@...el.com>
> Cc: Kai Huang <kai.huang@...el.com>
> Signed-off-by: Xin Li <xin3.li@...el.com>
> [sean: split to separate patch, write changelog]
> Reviewed-by: Kai Huang <kai.huang@...el.com>

Reviewed-by: Xiaoyao Li <xiaoyao.li@...el.com>

> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>   arch/x86/include/asm/vmx.h | 3 +--
>   arch/x86/kvm/vmx/vmx.c     | 2 +-
>   2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index 400819ccb42c..f7fd4369b821 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -153,7 +153,6 @@ static inline u64 vmx_basic_encode_vmcs_info(u32 revision, u16 size, u8 memtype)
>   	return revision | ((u64)size << 32) | ((u64)memtype << 50);
>   }
>   
> -#define VMX_MISC_PREEMPTION_TIMER_RATE_MASK	GENMASK_ULL(4, 0)
>   #define VMX_MISC_SAVE_EFER_LMA			BIT_ULL(5)
>   #define VMX_MISC_ACTIVITY_HLT			BIT_ULL(6)
>   #define VMX_MISC_ACTIVITY_SHUTDOWN		BIT_ULL(7)
> @@ -167,7 +166,7 @@ static inline u64 vmx_basic_encode_vmcs_info(u32 revision, u16 size, u8 memtype)
>   
>   static inline int vmx_misc_preemption_timer_rate(u64 vmx_misc)
>   {
> -	return vmx_misc & VMX_MISC_PREEMPTION_TIMER_RATE_MASK;
> +	return vmx_misc & GENMASK_ULL(4, 0);
>   }
>   
>   static inline int vmx_misc_cr3_count(u64 vmx_misc)
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 3141ef8679e2..69865e7a3506 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -8536,7 +8536,7 @@ __init int vmx_hardware_setup(void)
>   		u64 use_timer_freq = 5000ULL * 1000 * 1000;
>   
>   		cpu_preemption_timer_multi =
> -			vmcs_config.misc & VMX_MISC_PREEMPTION_TIMER_RATE_MASK;
> +			vmx_misc_preemption_timer_rate(vmcs_config.misc);
>   
>   		if (tsc_khz)
>   			use_timer_freq = (u64)tsc_khz * 1000;