[0/5] KVM: Remove kvm_is_transparent_hugepage() and friends

Message

Marc Zyngier July 17, 2021, 9:55 a.m. UTC

A while ago, Willy and Sean pointed out[1] that arm64 is the last user
of kvm_is_transparent_hugepage(), and that there would actually be
some benefit in looking at the userspace mapping directly instead.

This small series does exactly that, although it doesn't try to
support more than a PMD-sized mapping yet for THPs. We could probably
look into unifying this with the huge PUD code, and there is still
some potential use of the contiguous hint.

As a consequence, it removes kvm_is_transparent_hugepage(),
PageTransCompoundMap() and kvm_get_pfn(), all of which have no user
left after this rework.

This has been lightly tested on an Altra box. Although nothing caught
fire, it requires some careful reviewing on the arm64 side.

[1] https://lore.kernel.org/r/[e-mail]

Marc Zyngier (5):
  KVM: arm64: Walk userspace page tables to compute the THP mapping size
  KVM: arm64: Avoid mapping size adjustment on permission fault
  KVM: Remove kvm_is_transparent_hugepage() and PageTransCompoundMap()
  KVM: arm64: Use get_page() instead of kvm_get_pfn()
  KVM: Get rid of kvm_get_pfn()

 arch/arm64/kvm/mmu.c       | 57 +++++++++++++++++++++++++++++++++-----
 include/linux/kvm_host.h   |  1 -
 include/linux/page-flags.h | 37 -------------------------
 virt/kvm/kvm_main.c        | 19 +------------
 4 files changed, 51 insertions(+), 63 deletions(-)