[PATCH 0/5 v2] KVM: x86: MMU: Eliminate extra memory slot searches in page fault handlers

Takuya Yoshikawa
2015-10-16T07:50:23Z

v2: Based on Paolo's suggestion, kept the common code as much as possible by
introducing memslot_valid_for_gpte().

Note: instead of joining all checks by boolean operators, splitted the
no_dirty_log case off to be a separate if-check because it is checking
clearly different thing than the rest. See patch 4 for details.

In page fault handlers, both mapping_level_dirty_bitmap() and mapping_level()
do a memory slot search, binary search, through kvm_vcpu_gfn_to_memslot(), which
may not be negligible especially for virtual machines with many memory slots.

With a bit of cleanup effort, the patch set reduces this overhead.

Takuya

Takuya Yoshikawa (5):
KVM: x86: MMU: Make force_pt_level bool
KVM: x86: MMU: Simplify force_pt_level calculation code in FNAME(page_fault)()
KVM: x86: MMU: Merge mapping_level_dirty_bitmap() into mapping_level()
KVM: x86: MMU: Remove mapping_level_dirty_bitmap()
KVM: x86: MMU: Eliminate an extra memory slot search in mapping_level()

arch/x86/kvm/mmu.c | 70 +++++++++++++++++++++++++++-------------------
arch/x86/kvm/paging_tmpl.h | 19 ++++++-------
2 files changed, 50 insertions(+), 39 deletions(-)

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2.1.0