Re: [PATCH v2 12/13] KVM: x86: add SMM to the MMU role, support SMRAM address space

From	Paolo Bonzini <pbonzini@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 12/13] KVM: x86: add SMM to the MMU role, support SMRAM address space
Date	2015-06-18 09:10 +0200
Message-ID	<pCC7v-1eP-17@gated-at.bofh.it> (permalink)
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On 18/06/2015 07:02, Xiao Guangrong wrote:
> However, role->level is more hotter than role->smm so that it's also a good
> candidate for this kind of trick.

Right, we could give the first 8 bits to role->level, so it can be
accessed with a single memory load and extracted with a single AND.
Those two are definitely the hottest fields.

> And this is only 32 bits which can be operated in a CPU register by a
> single memory load, that is why i was worried if it is really needed.

However, an 8-bit field can be loaded from memory with a single movz
instruction.

Paolo
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Re: [PATCH v2 12/13] KVM: x86: add SMM to the MMU role, support SMRAM  address space Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-06-09 06:10 +0200
  Re: [PATCH v2 12/13] KVM: x86: add SMM to the MMU role, support SMRAM  address space Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-06-18 07:10 +0200
    Re: [PATCH v2 12/13] KVM: x86: add SMM to the MMU role, support SMRAM  address space Paolo Bonzini <pbonzini@redhat.com> - 2015-06-18 09:10 +0200

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