While investigating optimizing qemu start time for large memory guests I found that kvm_mmu_slot_apply_flags() is walking rmaps to update existing sptes when creating or moving a slot but that there won't be any existing sptes to update and any sptes inserted once the new memslot is visible won't need updating. I can't find any reason for this not to be the case, but I've taken a more cautious approach to fixing this by dividing things into three patches. Anthony Yznaga (3): KVM: x86: remove unnecessary rmap walk of read-only memslots KVM: x86: avoid unnecessary rmap walks when creating/moving slots KVM: x86: minor code refactor and comments fixup around dirty logging arch/x86/kvm/x86.c | 106 +++++++++++++++++++++++++---------------------------- 1 file changed, 49 insertions(+), 57 deletions(-) -- 2.13.3
