KVM: x86/mmu: Leverage vcpu->last_used_slot in tdp_mmu_map_handle_target_level

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The existing TDP MMU methods to handle dirty logging are vcpu-agnostic
since they can be driven by MMU notifiers and other non-vcpu-specific
events in addition to page faults. However this means that the TDP MMU
is not benefiting from the new vcpu->last_used_slot. Fix that by
introducing a tdp_mmu_map_set_spte_atomic() which is only called during
a TDP page fault and has access to the kvm_vcpu for fast slot lookups.

This improves "Populate memory time" in dirty_log_perf_test by 5%:

Command                         | Before           | After
------------------------------- | ---------------- | -------------
./dirty_log_perf_test -v64 -x64 | 5.472321072s     | 5.169832886s

Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20210804222844.1419481-5-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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David Matlack 2021-08-04 22:28:41 +00:00 • committed by Paolo Bonzini

parent fe22ed827c

commit 081de470f1

1 changed files with 33 additions and 9 deletions

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arch/x86/kvm/mmu/tdp_mmu.c

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