KVM: x86: only allocate gfn_track when necessary

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Avoid allocating the gfn_track arrays if nothing needs them. If there
are no external to KVM users of the API (i.e. no GVT-g), then page
tracking is only needed for shadow page tables. This means that when tdp
is enabled and there are no external users, then the gfn_track arrays
can be lazily allocated when the shadow MMU is actually used. This avoid
allocations equal to .05% of guest memory when nested virtualization is
not used, if the kernel is compiled without GVT-g.

Signed-off-by: David Stevens <stevensd@chromium.org>
Message-Id: <20210922045859.2011227-3-stevensd@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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David Stevens 2021-09-22 13:58:59 +09:00 • committed by Paolo Bonzini

parent e9d0c0c4f7

commit deae4a10f1

5 changed files with 93 additions and 8 deletions

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8

arch/x86/include/asm/kvm_host.h

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8

arch/x86/include/asm/kvm_page_track.h

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11

arch/x86/kvm/mmu/mmu.c

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72

arch/x86/kvm/mmu/page_track.c

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2

arch/x86/kvm/x86.c

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