KVM: x86/mmu: Dynamically allocate shadow MMU's hashed page list

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Dynamically allocate the (massive) array of hashed lists used to track
shadow pages, as the array itself is 32KiB, i.e. is an order-3 allocation
all on its own, and is *exactly* an order-3 allocation.  Dynamically
allocating the array will allow allocating "struct kvm" using kvmalloc(),
and will also allow deferring allocation of the array until it's actually
needed, i.e. until the first shadow root is allocated.

Opportunistically use kvmalloc() for the hashed lists, as an order-3
allocation is (stating the obvious) less likely to fail than an order-4
allocation, and the overhead of vmalloc() is undesirable given that the
size of the allocation is fixed.

Cc: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250523001138.3182794-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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This commit is contained in:

Sean Christopherson 2025-05-22 17:11:36 -07:00

parent 1f287a4e7b

commit 039ef33e2f

3 changed files with 28 additions and 4 deletions

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4

arch/x86/include/asm/kvm_host.h

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23

arch/x86/kvm/mmu/mmu.c

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5

arch/x86/kvm/x86.c

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