KVM: X86: Synchronize the shadow pagetable before link it

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If gpte is changed from non-present to present, the guest doesn't need
to flush tlb per SDM.  So the host must synchronze sp before
link it.  Otherwise the guest might use a wrong mapping.

For example: the guest first changes a level-1 pagetable, and then
links its parent to a new place where the original gpte is non-present.
Finally the guest can access the remapped area without flushing
the tlb.  The guest's behavior should be allowed per SDM, but the host
kvm mmu makes it wrong.

Fixes: 4731d4c7a0 ("KVM: MMU: out of sync shadow core")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210918005636.3675-3-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Lai Jiangshan 2021-09-18 08:56:28 +08:00 • committed by Paolo Bonzini

parent f81602958c

commit 65855ed8b0

2 changed files with 31 additions and 9 deletions

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17

arch/x86/kvm/mmu/mmu.c

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23

arch/x86/kvm/mmu/paging_tmpl.h

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