On 02/24/2016 09:17 PM, Paolo Bonzini wrote:
kvm_mmu_get_page is the only caller of kvm_sync_page_transient
and kvm_sync_pages. Moving the handling of the invalid_list there
removes the need for the underdocumented kvm_sync_page_transient
function.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
Guangrong, at this point I am confused about why
kvm_sync_page_transient didn't clear sp->unsync. Do
you remember? Or perhaps kvm_mmu_get_page could just
call kvm_sync_page now?
It is the optimization to reduce write-protect as changing unsync to
sync need to write-protect the page and sync all sptes pointing to the
same gfn.
However, after syncing the content between unsync-ed spte and guest pte,
we can reuse this spte perfectly.
Also, can you explain the need_sync variable in
kvm_mmu_get_page?
This is because we need to to protect the semanteme of 'unsync spte' as
only the spte on last level (level = 1) can be unsync so that if a spte
on the upper level is created we should eliminate all the unsync sptes
pointing to the same gfn.
As you have already merged this patchset to the kvm tree, i will post
a patch to comment these cases to make the code be more understandable.
