On 2/10/22 18:29, Sean Christopherson wrote:
On Thu, Feb 10, 2022, Paolo Bonzini wrote:
On 2/10/22 01:47, Sean Christopherson wrote:
The nested mess is likely easily solved, I don't see any obvious issue with swapping
the order. But I still don't love the subtlety. I do like shaving cycles, just
not the subtlety...
Not so easily, but it's doable and it's essentially what I did in the other
series (the one that reworks the root cache).
Sounds like I should reveiw that series first?
Yeah, this one is still a nice step in the direction of guest pt walk
from shadow pt build(*), but with no immediate use for TDP MMU root reuse.
The original idea was to use the MMU role to decide whether to do
kvm_mmu_unload(), but that would have still been a bandaid---inefficient
and a bad idea overall. Patches 6+7 of this series (once fixed, because
they were buggy as hell) turned out to be enough to tame the PGD cache
and remove kvm_mmu_unload() altogether from kvm_mmu_reset_context().
Paolo
(*) Your idea of detecting stale roots is quite easily implemented on
top of these, for example, because a root is stale if and only if the
root_role changes.
