[PATCH v2 0/4] KVM: x86/mmu: Cleanups for eager page splitting

[Sean Christopherson <seanjc@google.com>]

Eager page splitting cleanups for a few minor things that were noted in
code review but didn't make it into the committed code.

Patch 1 goes beyond the eager page splitting series, but it's still very
much relevant.

The last patch in particular is a bit more urgent than I first realized.
I had forgotten that pte_list_desc is now 128 bytes, and I also had a
brain fart and thought it was just allocating pointers, i.e. 8 bytes.
In other words, I was thinking the 513 object buffer was "only" wasting
~8kb per VM, whereas it actually costs ~64kb per VM.

v2:
 - Add helper to compute SPTE's index into its parent. [David].
 - Collect reviews [David].
 - Tweak the comment in the last patch after more analysis.

v1:
 - https://lore.kernel.org/all/20220624171808.2845941-1-seanjc@google.com

Sean Christopherson (4):
  KVM: x86/mmu: Add optimized helper to retrieve an SPTE's index
  KVM: x86/mmu: Expand quadrant comment for PG_LEVEL_4K shadow pages
  KVM: x86/mmu: Use "unsigned int", not "u32", for SPTEs' @access info
  KVM: x86/mmu: Buffer nested MMU split_desc_cache only by default
    capacity

 arch/x86/kvm/mmu/mmu.c         | 74 +++++++++++++++++++++-------------
 arch/x86/kvm/mmu/paging_tmpl.h |  4 +-
 arch/x86/kvm/mmu/spte.h        |  6 +++
 3 files changed, 53 insertions(+), 31 deletions(-)


base-commit: 4b88b1a518b337de1252b8180519ca4c00015c9e
-- 
2.37.0.rc0.161.g10f37bed90-goog