linux-kernel - Re: [PATCH v1 07/11] KVM: VMX: optimize APIC ID read with APICv

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Date:	Fri, 1 Jul 2016 10:42:54 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Radim Krčmář <rkrcmar@...hat.com>,
	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:	"Lan, Tianyu" <tianyu.lan@...el.com>,
	Igor Mammedov <imammedo@...hat.com>,
	Jan Kiszka <jan.kiszka@....de>, Peter Xu <peterx@...hat.com>
Subject: Re: [PATCH v1 07/11] KVM: VMX: optimize APIC ID read with APICv



On 30/06/2016 22:54, Radim Krčmář wrote:
> The register is in hardware-compatible format now, so there is not need
> to intercept.
> 
> Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
> ---
>  v1: new, split from the previous patch
> 
>  arch/x86/kvm/vmx.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 85e2f0a882ca..a10038258b80 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -6447,9 +6447,6 @@ static __init int hardware_setup(void)
>  	for (msr = 0x800; msr <= 0x8ff; msr++)
>  		vmx_disable_intercept_msr_read_x2apic(msr);
>  
> -	/* According SDM, in x2apic mode, the whole id reg is used.  But in
> -	 * KVM, it only use the highest eight bits. Need to intercept it */
> -	vmx_enable_intercept_msr_read_x2apic(0x802);
>  	/* TMCCT */
>  	vmx_enable_intercept_msr_read_x2apic(0x839);
>  	/* TPR */
> 

Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>