swiotlb: Free tbl memory in swiotlb_exit()

Although swiotlb_exit() frees the 'slots' metadata array referenced by
'io_tlb_default_mem', it leaves the underlying buffer pages allocated
despite no longer being usable.

Extend swiotlb_exit() to free the buffer pages as well as the slots
array.

Cc: Claire Chang <tientzu@chromium.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: NNathan Chancellor <nathan@kernel.org>
Tested-by: NClaire Chang <tientzu@chromium.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NWill Deacon <will@kernel.org>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad@kernel.org>

kernel/dma/swiotlb.c

@@ -328,18 +328,27 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 
 void __init swiotlb_exit(void)
 {
-	size_t size;
 	struct io_tlb_mem *mem = &io_tlb_default_mem;
+	unsigned long tbl_vaddr;
+	size_t tbl_size, slots_size;
 
 	if (!mem->nslabs)
 		return;
 
 	pr_info("tearing down default memory pool\n");
-	size = array_size(sizeof(*mem->slots), mem->nslabs);
-	if (mem->late_alloc)
-		free_pages((unsigned long)mem->slots, get_order(size));
-	else
-		memblock_free_late(__pa(mem->slots), PAGE_ALIGN(size));
+	tbl_vaddr = (unsigned long)phys_to_virt(mem->start);
+	tbl_size = PAGE_ALIGN(mem->end - mem->start);
+	slots_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), mem->nslabs));
+
+	set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT);
+	if (mem->late_alloc) {
+		free_pages(tbl_vaddr, get_order(tbl_size));
+		free_pages((unsigned long)mem->slots, get_order(slots_size));
+	} else {
+		memblock_free_late(mem->start, tbl_size);
+		memblock_free_late(__pa(mem->slots), slots_size);
+	}
+
 	memset(mem, 0, sizeof(*mem));
 }