3 files changed, 46 insertions, 19 deletions

diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 7c56d6b124d1..85c4593b634a 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -20,6 +20,7 @@ config KVM
 	select EXPORT_UASM
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
+	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_MMIO
 	select SRCU
 	---help---
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 01f3fa1b9f0e..0b84b336ee4d 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1086,42 +1086,46 @@ long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
 	return r;
 }
 
-/* Get (and clear) the dirty memory log for a memory slot. */
+/**
+ * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
+ * @kvm: kvm instance
+ * @log: slot id and address to which we copy the log
+ *
+ * Steps 1-4 below provide general overview of dirty page logging. See
+ * kvm_get_dirty_log_protect() function description for additional details.
+ *
+ * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
+ * always flush the TLB (step 4) even if previous step failed  and the dirty
+ * bitmap may be corrupt. Regardless of previous outcome the KVM logging API
+ * does not preclude user space subsequent dirty log read. Flushing TLB ensures
+ * writes will be marked dirty for next log read.
+ *
+ *   1. Take a snapshot of the bit and clear it if needed.
+ *   2. Write protect the corresponding page.
+ *   3. Copy the snapshot to the userspace.
+ *   4. Flush TLB's if needed.
+ */
 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
 	struct kvm_memslots *slots;
 	struct kvm_memory_slot *memslot;
-	unsigned long ga, ga_end;
-	int is_dirty = 0;
+	bool is_dirty = false;
 	int r;
-	unsigned long n;
 
 	mutex_lock(&kvm->slots_lock);
 
-	r = kvm_get_dirty_log(kvm, log, &is_dirty);
-	if (r)
-		goto out;
+	r = kvm_get_dirty_log_protect(kvm, log, &is_dirty);
 
-	/* If nothing is dirty, don't bother messing with page tables. */
 	if (is_dirty) {
 		slots = kvm_memslots(kvm);
 		memslot = id_to_memslot(slots, log->slot);
 
-		ga = memslot->base_gfn << PAGE_SHIFT;
-		ga_end = ga + (memslot->npages << PAGE_SHIFT);
-
-		kvm_info("%s: dirty, ga: %#lx, ga_end %#lx\n", __func__, ga,
-			 ga_end);
-
-		n = kvm_dirty_bitmap_bytes(memslot);
-		memset(memslot->dirty_bitmap, 0, n);
+		/* Let implementation handle TLB/GVA invalidation */
+		kvm_mips_callbacks->flush_shadow_memslot(kvm, memslot);
 	}
 
-	r = 0;
-out:
 	mutex_unlock(&kvm->slots_lock);
 	return r;
-
 }
 
 long kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 892fd0ede718..63a6d542ecb3 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -429,6 +429,28 @@ int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
 }
 
 /**
+ * kvm_arch_mmu_enable_log_dirty_pt_masked() - write protect dirty pages
+ * @kvm:	The KVM pointer
+ * @slot:	The memory slot associated with mask
+ * @gfn_offset:	The gfn offset in memory slot
+ * @mask:	The mask of dirty pages at offset 'gfn_offset' in this memory
+ *		slot to be write protected
+ *
+ * Walks bits set in mask write protects the associated pte's. Caller must
+ * acquire @kvm->mmu_lock.
+ */
+void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
+		struct kvm_memory_slot *slot,
+		gfn_t gfn_offset, unsigned long mask)
+{
+	gfn_t base_gfn = slot->base_gfn + gfn_offset;
+	gfn_t start = base_gfn +  __ffs(mask);
+	gfn_t end = base_gfn + __fls(mask);
+
+	kvm_mips_mkclean_gpa_pt(kvm, start, end);
+}
+
+/**
  * kvm_mips_map_page() - Map a guest physical page.
  * @vcpu:		VCPU pointer.
  * @gpa:		Guest physical address of fault.