Re: [PATCH 1/2] KVM: x86: disable MPX if host did not enable MPX XSAVE features

[Paolo Bonzini]

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.