Re: [PATCH RFC] KVM: x86: mmu: don't re-generate permissions/pkru_mask bitmasks when source is unchanged

From: Vitaly Kuznetsov
Date: Mon Jul 09 2018 - 12:33:34 EST

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In reply to: Vitaly Kuznetsov: "[PATCH RFC] KVM: x86: mmu: don't re-generate permissions/pkru_mask bitmasks when source is unchanged 1;5004;0c update_permission_bitmask()/update_pkru_bitmask() are rarely called under normal circumstances but nesting changes everything. E.g. for nVMX we call kvm_mmu_reset_context() from nested_vmx_load_cr3() which happens on nested vmexit/vmentry. init_kvm_mmu() in its turn call init_kvm_nested_mmu() or init_kvm_tdp_mmu() (which operate on arch.nested_mmu and arch.mmu respectively) which unconditionally do update_permission_bitmask()/ update_pkru_bitmask()."
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Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes:

> ...

I'm sorry for the screwed up Subject line)

--
Vitaly