On 23/06/20 21:35, Sean Christopherson wrote:
> Semi-random, but related, changes that deal with the handling of active
> root shadow pages during zapping and the zapping of arbitary/old pages.
>
> Patch 1 changes the low level handling to keep zapped active roots off the
> active page list. KVM already relies on the vCPU to explicitly free the
> root, putting invalid root pages back on the list is just a quirk of the
> implementation.
>
> Patches 2 reworks the MMU page recycling to batch zap pages instead of
> zapping them one at a time. This provides better handling for active root
> pages and also avoids multiple remote TLB flushes.
>
> Patch 3 applies the batch zapping to the .shrink_scan() path. This is a
> significant change in behavior, i.e. is the scariest of the changes, but
> unless I'm missing something it provides the intended functionality that
> has been lacking since shrinker support was first added.
>
> Patch 4 changes the page fault handlers to return an error to userspace
> instead of restarting the guest if there are no MMU pages available. This
> is dependent on patch 2 as theoretically the old recycling flow could
> prematurely bail if it encountered an active root.
>
> v2:
> - Add a comment for the list shenanigans in patch 1. [Paolo]
> - Add patches 2-4.
> - Rebased to kvm/queue, commit a037ff353ba6 ("Merge branch ...")
>
> Sean Christopherson (4):
> KVM: x86/mmu: Don't put invalid SPs back on the list of active pages
> KVM: x86/mmu: Batch zap MMU pages when recycling oldest pages
> KVM: x86/mmu: Batch zap MMU pages when shrinking the slab
> KVM: x86/mmu: Exit to userspace on make_mmu_pages_available() error
>
> arch/x86/kvm/mmu/mmu.c | 94 +++++++++++++++++++++-------------
> arch/x86/kvm/mmu/paging_tmpl.h | 3 +-
> 2 files changed, 61 insertions(+), 36 deletions(-)
>
Queued, thanks.
Paolo
