KVM: MMU: Add mmu help functions to support PML

This patch adds new mmu layer functions to clear/set D-bit for memory slot, and
to write protect superpages for memory slot.

In case of PML, CPU logs the dirty GPA automatically to PML buffer when CPU
updates D-bit from 0 to 1, therefore we don't have to write protect 4K pages,
instead, we only need to clear D-bit in order to log that GPA.

For superpages, we still write protect it and let page fault code to handle
dirty page logging, as we still need to split superpage to 4K pages in PML.

As PML is always enabled during guest's lifetime, to eliminate unnecessary PML
GPA logging, we set D-bit manually for the slot with dirty logging disabled.

Signed-off-by: Kai Huang <kai.huang@linux.intel.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 843bea0..4f6369b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -835,6 +835,15 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 
 void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);
+void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
+				   struct kvm_memory_slot *memslot);
+void kvm_mmu_slot_largepage_remove_write_access(struct kvm *kvm,
+					struct kvm_memory_slot *memslot);
+void kvm_mmu_slot_set_dirty(struct kvm *kvm,
+			    struct kvm_memory_slot *memslot);
+void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
+				   struct kvm_memory_slot *slot,
+				   gfn_t gfn_offset, unsigned long mask);
 void kvm_mmu_zap_all(struct kvm *kvm);
 void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm);
 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm);