Thanks,I found everytime KVM creates a new kvm_mmu_page,it instert it
to hash list,but why the list have alweady existed SP corresponding
to specific gfn??
how KVM maintain the hash list??
thanks
2017-03-01 11:40 GMT+08:00 Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>:
>
> Hash list is used as a cache. KVM is always trying to reuse the
> existing SP if possible.
>
>
>
> On 03/01/2017 10:46 AM, jack.chen wrote:
>>
>> hello,I am confused about kvm_mmu_get_page function in KVM source
>> code,why it look for a the hash list first rather than alloc a new
>> page, what is the function of the hash list.thanks!
>> for_each_gfn_sp(vcpu->kvm, sp, gfn) {
>>
>> if (is_obsolete_sp(vcpu->kvm, sp))
>> continue;
>>
>> if (!need_sync && sp->unsync)
>> need_sync = true;
>>
>> if (sp->role.word != role.word)
>> continue;
>>
>> if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
>> break;
>>
>> mmu_page_add_parent_pte(vcpu, sp, parent_pte);
>> if (sp->unsync_children) {
>> kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
>> kvm_mmu_mark_parents_unsync(sp);
>> } else if (sp->unsync)
>> kvm_mmu_mark_parents_unsync(sp);
>>
>> __clear_sp_write_flooding_count(sp);
>> trace_kvm_mmu_get_page(sp, false);
>> return sp;
>> }
>>
>
