[v4,0/5] KVM: Unify mmu_memory_cache functionality across architectures

Message

Christoffer Dall Nov. 5, 2019, 11:03 a.m. UTC

We currently have duplicated functionality for the mmu_memory_cache used
to pre-allocate memory for the page table manipulation code which cannot
allocate memory while holding spinlocks.  This functionality is
duplicated across x86, arm/arm64, and mips.

This was motivated by a debate of modifying the arm code to be more in
line with the x86 code and some discussions around changing the page
flags used for allocation.  This series should make it easier to take a
uniform approach across architectures.

While there's not a huge amount of code sharing, we come out with a net
gain, and the real win is in the consistency of how we allocate memory
for page tables used by secondary MMUs driven by KVM in Linux.

Only tested on arm/arm64, and only compile-tested on x86 and mips.  I'm
especially curious on getting feedback on the change of GFP flags for
x86 (patch 1) and on the use of __GFP_ACCOUNT for mips.

Changes since v3:
 - Moved to common GFP_PGTABLE_USER definition for page allocations in
   the MMU cache for all three architectures.  This follows recent work
   which already did this for arm/arm64.
 - Rebased on v5.4-rc4.

Changes since v2:
 - Simplified kalloc flag definitions as per Paolo's review comment.

Changes since v1:
 - Split out rename from initial x86 patch to have separate patches to
   move the logic to common code and to rename.
 - Introduce KVM_ARCH_WANT_MMU_MEMCACHE to avoid compile breakage on
   architectures that don't use this functionality.
 - Rename KVM_NR_MEM_OBJS to KVM_MMU_NR_MEMCACHE_OBJS

Christoffer Dall (5):
  KVM: x86: Move memcache allocation to GFP_PGTABLE_USER
  KVM: x86: Move mmu_memory_cache functions to common code
  KVM: x86: Rename mmu_memory_cache to kvm_mmu_memcache
  KVM: arm/arm64: Move to common kvm_mmu_memcache infrastructure
  KVM: mips: Move to common kvm_mmu_memcache infrastructure

 arch/arm/include/asm/kvm_host.h      | 13 +---
 arch/arm/include/asm/kvm_mmu.h       |  2 +-
 arch/arm/include/asm/kvm_types.h     |  9 +++
 arch/arm64/include/asm/kvm_host.h    | 13 +---
 arch/arm64/include/asm/kvm_mmu.h     |  2 +-
 arch/arm64/include/asm/kvm_types.h   |  9 +++
 arch/mips/include/asm/kvm_host.h     | 15 +----
 arch/mips/include/asm/kvm_types.h    |  9 +++
 arch/mips/kvm/mips.c                 |  2 +-
 arch/mips/kvm/mmu.c                  | 54 +++-------------
 arch/powerpc/include/asm/kvm_types.h |  5 ++
 arch/s390/include/asm/kvm_types.h    |  5 ++
 arch/x86/include/asm/kvm_host.h      | 17 +----
 arch/x86/include/asm/kvm_types.h     |  9 +++
 arch/x86/kvm/mmu.c                   | 97 ++++++----------------------
 arch/x86/kvm/paging_tmpl.h           |  4 +-
 include/linux/kvm_host.h             | 11 ++++
 include/linux/kvm_types.h            | 13 ++++
 virt/kvm/arm/arm.c                   |  2 +-
 virt/kvm/arm/mmu.c                   | 68 +++++--------------
 virt/kvm/kvm_main.c                  | 61 +++++++++++++++++
 21 files changed, 190 insertions(+), 230 deletions(-)
 create mode 100644 arch/arm/include/asm/kvm_types.h
 create mode 100644 arch/arm64/include/asm/kvm_types.h
 create mode 100644 arch/mips/include/asm/kvm_types.h
 create mode 100644 arch/powerpc/include/asm/kvm_types.h
 create mode 100644 arch/s390/include/asm/kvm_types.h
 create mode 100644 arch/x86/include/asm/kvm_types.h