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From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Zhang <yang.zhang.wz@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Xiao Guangrong <guangrong.xiao@linux.intel.com>
Subject: Re: [PATCH 1/2] KVM: x86: disable MPX if host did not enable MPX XSAVE features
Date: Thu, 24 Mar 2016 14:07:55 +0100	[thread overview]
Message-ID: <56F3E6AB.5070902@redhat.com> (raw)
In-Reply-To: <56F3E653.6040901@gmail.com>



On 24/03/2016 14:06, Yang Zhang wrote:
> 
> I mean why not keep the old way that only activate the eager_fpu while
> guest sees the MPX bit in CPUID, like:
> 
> vcpu->arch.eager_fpu = use_eager_fpu() && guest_cpuid_has_mpx(vcpu);

If the host uses eager FPU you can assume that it's faster than lazy FPU.

Paolo

> Besides, vmx_fpu_activate is called when do vcpu_reset. So it seems no
> need to call fpu_activate() here again.

  reply	other threads:[~2016-03-24 13:08 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-08 11:44 [PATCH 0/2] " Paolo Bonzini
2016-03-08 11:44 ` [PATCH 1/2] " Paolo Bonzini
     [not found]   ` <CA+3C=r-NVn__gPVdYRSypzjfejRBgB4VVY5OpckS2QGjXnUu2Q@mail.gmail.com>
2016-03-11 12:09     ` Paolo Bonzini
2016-03-24 13:06       ` Yang Zhang
2016-03-24 13:07         ` Paolo Bonzini [this message]
2016-04-13  9:47           ` Yang Zhang
2016-05-10 12:38             ` Paolo Bonzini
2016-03-08 11:44 ` [PATCH 2/2] KVM: x86: remove eager_fpu field of struct kvm_vcpu_arch Paolo Bonzini
2016-03-10 12:28 ` [PATCH 0/2] KVM: x86: disable MPX if host did not enable MPX XSAVE features Xiao Guangrong
2016-03-10 12:30   ` Paolo Bonzini
2016-03-10 17:35     ` Ingo Molnar
2016-03-10 17:38       ` Paolo Bonzini

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