Re: [PATCH 0/3] KVM: x86/mmu: Cleanups for eager page splitting

From: Paolo Bonzini
Date: Sat Jun 25 2022 - 04:55:18 EST


On 6/24/22 19:18, Sean Christopherson wrote:
Eager page splitting cleanups for a few minor things that were noted in
code review but didn't make it into the committed code.

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.

Sean Christopherson (3):
KVM: x86/mmu: Avoid subtle pointer arithmetic in kvm_mmu_child_role()
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 | 53 ++++++++++++++++++++++++++++--------------
1 file changed, 35 insertions(+), 18 deletions(-)


base-commit: 4b88b1a518b337de1252b8180519ca4c00015c9e

Queued 2+3.

Paolo