vm: evict PTE entries for transferred vm-object pages

include/kernel/address-space.h

@@ -17,6 +17,8 @@ struct vm_area {
 	 * will avoid the area, but fixed address mappings in this area
 	 * will succeed. */
 	struct vm_object *vma_object;
+	/* the address space that this vm_area is a part of */
+	struct address_space *vma_space;
 	/* used to link to vm_object->vo_mappings */
 	struct queue_entry vma_object_entry;
 	/* the memory protection flags applied to this area */

vm/address-space.c

@@ -659,6 +659,7 @@ kern_status_t address_space_map(
 	}
 
 	object_ref(&object->vo_base);
+	area->vma_space = root;
 	area->vma_object = object;
 	area->vma_prot = prot;
 	area->vma_object_offset = object_offset;
@@ -726,6 +727,7 @@ static kern_status_t split_area(
 	left->vma_base = left_base;
 	left->vma_limit = left_base + left_length - 1;
 
+	right->vma_space = left->vma_space;
 	right->vma_object = left->vma_object;
 	right->vma_prot = left->vma_prot;
 	right->vma_object_offset = right_object_offset;
@@ -983,6 +985,7 @@ kern_status_t address_space_reserve(
 		return KERN_NO_MEMORY;
 	}
 
+	area->vma_space = space;
 	area->vma_base = base;
 	area->vma_limit = base + length - 1;
 
@@ -1142,6 +1145,7 @@ static kern_status_t request_missing_page(
 		irq_flags);
 	if (!pg) {
 		vm_object_unlock_irqrestore(object, *irq_flags);
+		printk("page request for %zx failed", addr);
 		return KERN_FATAL_ERROR;
 	}
 
@@ -1203,8 +1207,12 @@ kern_status_t address_space_demand_map(
 		object_offset,
 		VMO_ALLOCATE_MISSING_PAGE,
 		NULL);
-	// tracek("vm: mapping %07llx -> %10llx", vm_page_get_paddr(pg),
-	// addr);
+	// tracek("vm: mapping %07llx -> %10llx", vm_page_get_paddr(pg), addr);
+
+	if (!pg) {
+		return KERN_FATAL_ERROR;
+	}
+
 	kern_status_t status = pmap_add(
 		region->s_pmap,
 		addr,

vm/vm-object.c

@@ -1,4 +1,4 @@
-#include <kernel/printk.h>
+#include <kernel/address-space.h>
 #include <kernel/sched.h>
 #include <kernel/util.h>
 #include <kernel/vm-controller.h>
@@ -236,7 +236,6 @@ extern struct vm_object *vm_object_create_in_place(
 	     i += VM_PAGE_SIZE, offset += VM_PAGE_SIZE) {
 		struct vm_page *pg = vm_page_get(i);
 		if (!pg) {
-			printk("vm-object: invalid physical address %08llx", i);
 			object_unref(&vmo->vo_base);
 			return NULL;
 		}
@@ -871,8 +870,35 @@ kern_status_t vm_object_transfer(
 		moved += VM_PAGE_SIZE;
 	}
 
-	/* TODO evict all page table entries that reference the transferred
-	 * pages in `src` */
+	struct queue_entry *cur = queue_first(&src->vo_mappings);
+	off_t src_limit = src_offset + count - 1;
+	while (cur) {
+		struct vm_area *area = QUEUE_CONTAINER(
+			struct vm_area,
+			vma_object_entry,
+			cur);
+		off_t area_offset = area->vma_object_offset;
+		off_t area_limit
+			= area_offset + (area->vma_limit - area->vma_base);
+
+		if (src_offset > area_limit || src_limit < area_offset) {
+			cur = queue_next(cur);
+			continue;
+		}
+
+		off_t unmap_offset = MAX(area_offset, src_offset);
+		off_t unmap_limit = MIN(area_limit, src_limit);
+
+		virt_addr_t base
+			= area->vma_base + (unmap_offset - area_offset);
+		virt_addr_t limit = base + (unmap_limit - unmap_offset);
+
+		for (virt_addr_t i = base; i < limit; i += VM_PAGE_SIZE) {
+			pmap_remove(area->vma_space->s_pmap, i);
+		}
+
+		cur = queue_next(cur);
+	}
 
 	if (nr_moved) {
 		*nr_moved = moved;