A while ago, Willy and Sean pointed out[0] 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 (VHE) and on a SC2A11
system (nVHE). Although nothing caught fire, it requires some careful
reviewing on the arm64 side.
* From v1 [1]:
- Move the PT helper into its own function, as both Quentin and I
need it for other developments
- Fixed stupid bug introduced by a bad conflict resolution, spotted
by Alexandru
- Collected Acks from Paolo, with thanks
[0] https://lore.kernel.org/r/YLpLvFPXrIp8nAK4@xxxxxxxxxx
[1] https://lore.kernel.org/r/20210717095541.1486210-1-maz@xxxxxxxxxx
Marc Zyngier (6):
KVM: arm64: Introduce helper to retrieve a PTE and its level
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/include/asm/kvm_pgtable.h | 19 ++++++++++++
arch/arm64/kvm/hyp/pgtable.c | 39 ++++++++++++++++++++++++
arch/arm64/kvm/mmu.c | 45 +++++++++++++++++++++++-----
include/linux/kvm_host.h | 1 -
include/linux/page-flags.h | 37 -----------------------
virt/kvm/kvm_main.c | 19 +-----------
6 files changed, 97 insertions(+), 63 deletions(-)
--
2.30.2
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