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;
}
