| Message ID | 20240315230541.1635322-4-dmatlack@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86/mmu: Fix TDP MMU dirty logging bug L2 running with EPT disabled | expand |
On Fri, Mar 15, 2024, David Matlack wrote: > 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> > --- > arch/x86/kvm/mmu/tdp_mmu.c | 16 ++++++---------- > 1 file changed, 6 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index 01192ac760f1..1e9b48b5f6e1 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -1544,11 +1544,9 @@ 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) > @@ -1606,11 +1604,9 @@ 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. > + * Clears the dirty status (D-bit or W-bit) of all the 4k SPTEs mapping GFNs for Heh, purely because it stood out when reading the two comments back-to-back, I I opportunistically used "Clear" instead of "Clears" so that the comments use similar tone. > + * 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, > -- > 2.44.0.291.gc1ea87d7ee-goog >
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 01192ac760f1..1e9b48b5f6e1 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1544,11 +1544,9 @@ 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) @@ -1606,11 +1604,9 @@ 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. + * Clears 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,
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> --- arch/x86/kvm/mmu/tdp_mmu.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-)