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KVM: x86/mmu: Fix and clarify comments about clearing D-bit vs. write-protecting 

Drop the "If AD bits are enabled/disabled" verbiage from the comments
above kvm_tdp_mmu_clear_dirty_{slot,pt_masked}() since TDP MMU SPTEs may
need to be write-protected even when A/D bits are enabled. i.e. These
comments aren't technically correct.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240315230541.1635322-4-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
David Matlack 2024-03-15 16:05:40 -07:00 committed by Sean Christopherson
parent feac19aa4c
commit b1a8d2b02b
1 changed files with 6 additions and 10 deletions
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16
arch/x86/kvm/mmu/tdp_mmu.c
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@ -1594,11 +1594,9 @@ retry:
}
/*
* Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If
* AD bits are enabled, this will involve clearing the dirty bit on each SPTE.
* If AD bits are not enabled, this will require clearing the writable bit on
* each SPTE. Returns true if an SPTE has been changed and the TLBs need to
* be flushed.
* Clear the dirty status (D-bit or W-bit) of all the SPTEs mapping GFNs in the
* memslot. Returns true if an SPTE has been changed and the TLBs need to be
* flushed.
*/
bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm,
const struct kvm_memory_slot *slot)
@ -1656,11 +1654,9 @@ static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root,
}
/*
* Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is
* set in mask, starting at gfn. The given memslot is expected to contain all
* the GFNs represented by set bits in the mask. If AD bits are enabled,
* clearing the dirty status will involve clearing the dirty bit on each SPTE
* or, if AD bits are not enabled, clearing the writable bit on each SPTE.
* Clear the dirty status (D-bit or W-bit) of all the 4k SPTEs mapping GFNs for
* which a bit is set in mask, starting at gfn. The given memslot is expected to
* contain all the GFNs represented by set bits in the mask.
*/
void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,