Commit b1a8d2b0 authored by David Matlack's avatar David Matlack Committed by Sean Christopherson
Browse files

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: default avatarDavid Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240315230541.1635322-4-dmatlack@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent feac19aa

arch/x86/kvm/mmu/tdp_mmu.c

+6 −10
Original line number Diff line number Diff line
@@ -1594,11 +1594,9 @@ static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, 
}



/*

 * 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,