Il 03/07/2013 10:53, Gleb Natapov ha scritto: >>> > > Please wait a while. I can not understand it very clearly. >>> > > >>> > > This conditional check will cause caching a overflow value into mmio >>> > > spte. >>> > > The simple case is that kvm adds new slots for many times, the mmio-gen >>> > > is easily >>> > > more than MMIO_MAX_GEN. >>> > > >> > >> > Actually, the double zapping can be avoided by moving >> > kvm_mmu_invalidate_mmio_sptes to >> > the end of install_new_memslots(). >> > > Exactly. Why should we hide it in obscure functions?
Because kvm_mmu_invalidate_mmio_sptes is an x86-specific function, and we already have a good arch API to hook into __kvm_set_memory_region. Another possible implementation is to cache the last memslot generation, check it in kvm_arch_prepare/commit_memory_region, and call kvm_mmu_invalidate_mmio_sptes if it changed. This would avoid the need to keep "((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE))" in sync between the two places. But I don't think it is a substantial improvement. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
