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Subject: [PATCH RFC v1 2/6] swiotlb: convert variables to arrays
Date:   Wed,  3 Feb 2021 15:37:05 -0800
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This patch converts several swiotlb related variables to arrays, in
order to maintain stat/status for different swiotlb buffers. Here are
variables involved:

- io_tlb_start and io_tlb_end
- io_tlb_nslabs and io_tlb_used
- io_tlb_list
- io_tlb_index
- max_segment
- io_tlb_orig_addr
- no_iotlb_memory

There is no functional change and this is to prepare to enable 64-bit
swiotlb.

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
 arch/powerpc/platforms/pseries/svm.c |   6 +-
 drivers/xen/swiotlb-xen.c            |   4 +-
 include/linux/swiotlb.h              |   5 +-
 kernel/dma/swiotlb.c                 | 257 ++++++++++++++-------------
 4 files changed, 140 insertions(+), 132 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index 7b739cc7a8a9..9f8842d0da1f 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -55,9 +55,9 @@ void __init svm_swiotlb_init(void)
 	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, false))
 		return;
 
-	if (io_tlb_start)
-		memblock_free_early(io_tlb_start,
-				    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
+	if (io_tlb_start[SWIOTLB_LO])
+		memblock_free_early(io_tlb_start[SWIOTLB_LO],
+				    PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT));
 	panic("SVM: Cannot allocate SWIOTLB buffer");
 }
 
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 2b385c1b4a99..3261880ad859 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -192,8 +192,8 @@ int __ref xen_swiotlb_init(int verbose, bool early)
 	/*
 	 * IO TLB memory already allocated. Just use it.
 	 */
-	if (io_tlb_start != 0) {
-		xen_io_tlb_start = phys_to_virt(io_tlb_start);
+	if (io_tlb_start[SWIOTLB_LO] != 0) {
+		xen_io_tlb_start = phys_to_virt(io_tlb_start[SWIOTLB_LO]);
 		goto end;
 	}
 
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index ca125c1b1281..777046cd4d1b 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -76,11 +76,12 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
-extern phys_addr_t io_tlb_start, io_tlb_end;
+extern phys_addr_t io_tlb_start[], io_tlb_end[];
 
 static inline bool is_swiotlb_buffer(phys_addr_t paddr)
 {
-	return paddr >= io_tlb_start && paddr < io_tlb_end;
+	return paddr >= io_tlb_start[SWIOTLB_LO] &&
+	       paddr < io_tlb_end[SWIOTLB_LO];
 }
 
 void __init swiotlb_exit(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 7c42df6e6100..1fbb65daa2dd 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -69,38 +69,38 @@ enum swiotlb_force swiotlb_force;
  * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
  * API.
  */
-phys_addr_t io_tlb_start, io_tlb_end;
+phys_addr_t io_tlb_start[SWIOTLB_MAX], io_tlb_end[SWIOTLB_MAX];
 
 /*
  * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
  * io_tlb_end.  This is command line adjustable via setup_io_tlb_npages.
  */
-static unsigned long io_tlb_nslabs;
+static unsigned long io_tlb_nslabs[SWIOTLB_MAX];
 
 /*
  * The number of used IO TLB block
  */
-static unsigned long io_tlb_used;
+static unsigned long io_tlb_used[SWIOTLB_MAX];
 
 /*
  * This is a free list describing the number of free entries available from
  * each index
  */
-static unsigned int *io_tlb_list;
-static unsigned int io_tlb_index;
+static unsigned int *io_tlb_list[SWIOTLB_MAX];
+static unsigned int io_tlb_index[SWIOTLB_MAX];
 
 /*
  * Max segment that we can provide which (if pages are contingous) will
  * not be bounced (unless SWIOTLB_FORCE is set).
  */
-static unsigned int max_segment;
+static unsigned int max_segment[SWIOTLB_MAX];
 
 /*
  * We need to save away the original address corresponding to a mapped entry
  * for the sync operations.
  */
 #define INVALID_PHYS_ADDR (~(phys_addr_t)0)
-static phys_addr_t *io_tlb_orig_addr;
+static phys_addr_t *io_tlb_orig_addr[SWIOTLB_MAX];
 
 /*
  * Protect the above data structures in the map and unmap calls
@@ -113,9 +113,9 @@ static int __init
 setup_io_tlb_npages(char *str)
 {
 	if (isdigit(*str)) {
-		io_tlb_nslabs = simple_strtoul(str, &str, 0);
+		io_tlb_nslabs[SWIOTLB_LO] = simple_strtoul(str, &str, 0);
 		/* avoid tail segment of size < IO_TLB_SEGSIZE */
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+		io_tlb_nslabs[SWIOTLB_LO] = ALIGN(io_tlb_nslabs[SWIOTLB_LO], IO_TLB_SEGSIZE);
 	}
 	if (*str == ',')
 		++str;
@@ -123,40 +123,40 @@ setup_io_tlb_npages(char *str)
 		swiotlb_force = SWIOTLB_FORCE;
 	} else if (!strcmp(str, "noforce")) {
 		swiotlb_force = SWIOTLB_NO_FORCE;
-		io_tlb_nslabs = 1;
+		io_tlb_nslabs[SWIOTLB_LO] = 1;
 	}
 
 	return 0;
 }
 early_param("swiotlb", setup_io_tlb_npages);
 
-static bool no_iotlb_memory;
+static bool no_iotlb_memory[SWIOTLB_MAX];
 
 unsigned long swiotlb_nr_tbl(void)
 {
-	return unlikely(no_iotlb_memory) ? 0 : io_tlb_nslabs;
+	return unlikely(no_iotlb_memory[SWIOTLB_LO]) ? 0 : io_tlb_nslabs[SWIOTLB_LO];
 }
 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
 
 unsigned int swiotlb_max_segment(void)
 {
-	return unlikely(no_iotlb_memory) ? 0 : max_segment;
+	return unlikely(no_iotlb_memory[SWIOTLB_LO]) ? 0 : max_segment[SWIOTLB_LO];
 }
 EXPORT_SYMBOL_GPL(swiotlb_max_segment);
 
 void swiotlb_set_max_segment(unsigned int val)
 {
 	if (swiotlb_force == SWIOTLB_FORCE)
-		max_segment = 1;
+		max_segment[SWIOTLB_LO] = 1;
 	else
-		max_segment = rounddown(val, PAGE_SIZE);
+		max_segment[SWIOTLB_LO] = rounddown(val, PAGE_SIZE);
 }
 
 unsigned long swiotlb_size_or_default(void)
 {
 	unsigned long size;
 
-	size = io_tlb_nslabs << IO_TLB_SHIFT;
+	size = io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT;
 
 	return size ? size : (IO_TLB_DEFAULT_SIZE);
 }
@@ -170,10 +170,10 @@ void __init swiotlb_adjust_size(unsigned long new_size)
 	 * architectures such as those supporting memory encryption to
 	 * adjust/expand SWIOTLB size for their use.
 	 */
-	if (!io_tlb_nslabs) {
+	if (!io_tlb_nslabs[SWIOTLB_LO]) {
 		size = ALIGN(new_size, 1 << IO_TLB_SHIFT);
-		io_tlb_nslabs = size >> IO_TLB_SHIFT;
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+		io_tlb_nslabs[SWIOTLB_LO] = size >> IO_TLB_SHIFT;
+		io_tlb_nslabs[SWIOTLB_LO] = ALIGN(io_tlb_nslabs[SWIOTLB_LO], IO_TLB_SEGSIZE);
 
 		pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20);
 	}
@@ -181,15 +181,16 @@ void __init swiotlb_adjust_size(unsigned long new_size)
 
 void swiotlb_print_info(void)
 {
-	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+	unsigned long bytes = io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT;
 
-	if (no_iotlb_memory) {
+	if (no_iotlb_memory[SWIOTLB_LO]) {
 		pr_warn("No low mem\n");
 		return;
 	}
 
-	pr_info("mapped [mem %pa-%pa] (%luMB)\n", &io_tlb_start, &io_tlb_end,
-	       bytes >> 20);
+	pr_info("mapped [mem %pa-%pa] (%luMB)\n",
+		&io_tlb_start[SWIOTLB_LO], &io_tlb_end[SWIOTLB_LO],
+		bytes >> 20);
 }
 
 /*
@@ -203,11 +204,11 @@ void __init swiotlb_update_mem_attributes(void)
 	void *vaddr;
 	unsigned long bytes;
 
-	if (no_iotlb_memory || late_alloc)
+	if (no_iotlb_memory[SWIOTLB_LO] || late_alloc)
 		return;
 
-	vaddr = phys_to_virt(io_tlb_start);
-	bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
+	vaddr = phys_to_virt(io_tlb_start[SWIOTLB_LO]);
+	bytes = PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT);
 	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
 	memset(vaddr, 0, bytes);
 }
@@ -219,38 +220,38 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 
 	bytes = nslabs << IO_TLB_SHIFT;
 
-	io_tlb_nslabs = nslabs;
-	io_tlb_start = __pa(tlb);
-	io_tlb_end = io_tlb_start + bytes;
+	io_tlb_nslabs[SWIOTLB_LO] = nslabs;
+	io_tlb_start[SWIOTLB_LO] = __pa(tlb);
+	io_tlb_end[SWIOTLB_LO] = io_tlb_start[SWIOTLB_LO] + bytes;
 
 	/*
 	 * Allocate and initialize the free list array.  This array is used
 	 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
 	 * between io_tlb_start and io_tlb_end.
 	 */
-	alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(int));
-	io_tlb_list = memblock_alloc(alloc_size, PAGE_SIZE);
-	if (!io_tlb_list)
+	alloc_size = PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] * sizeof(int));
+	io_tlb_list[SWIOTLB_LO] = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!io_tlb_list[SWIOTLB_LO])
 		panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
 		      __func__, alloc_size, PAGE_SIZE);
 
-	alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t));
-	io_tlb_orig_addr = memblock_alloc(alloc_size, PAGE_SIZE);
-	if (!io_tlb_orig_addr)
+	alloc_size = PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] * sizeof(phys_addr_t));
+	io_tlb_orig_addr[SWIOTLB_LO] = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!io_tlb_orig_addr[SWIOTLB_LO])
 		panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
 		      __func__, alloc_size, PAGE_SIZE);
 
-	for (i = 0; i < io_tlb_nslabs; i++) {
-		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
-		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+	for (i = 0; i < io_tlb_nslabs[SWIOTLB_LO]; i++) {
+		io_tlb_list[SWIOTLB_LO][i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+		io_tlb_orig_addr[SWIOTLB_LO][i] = INVALID_PHYS_ADDR;
 	}
-	io_tlb_index = 0;
-	no_iotlb_memory = false;
+	io_tlb_index[SWIOTLB_LO] = 0;
+	no_iotlb_memory[SWIOTLB_LO] = false;
 
 	if (verbose)
 		swiotlb_print_info();
 
-	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+	swiotlb_set_max_segment(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT);
 	return 0;
 }
 
@@ -265,25 +266,25 @@ swiotlb_init(int verbose)
 	unsigned char *vstart;
 	unsigned long bytes;
 
-	if (!io_tlb_nslabs) {
-		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+	if (!io_tlb_nslabs[SWIOTLB_LO]) {
+		io_tlb_nslabs[SWIOTLB_LO] = (default_size >> IO_TLB_SHIFT);
+		io_tlb_nslabs[SWIOTLB_LO] = ALIGN(io_tlb_nslabs[SWIOTLB_LO], IO_TLB_SEGSIZE);
 	}
 
-	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+	bytes = io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT;
 
 	/* Get IO TLB memory from the low pages */
 	vstart = memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE);
-	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
+	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs[SWIOTLB_LO], verbose))
 		return;
 
-	if (io_tlb_start) {
-		memblock_free_early(io_tlb_start,
-				    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
-		io_tlb_start = 0;
+	if (io_tlb_start[SWIOTLB_LO]) {
+		memblock_free_early(io_tlb_start[SWIOTLB_LO],
+				    PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT));
+		io_tlb_start[SWIOTLB_LO] = 0;
 	}
 	pr_warn("Cannot allocate buffer");
-	no_iotlb_memory = true;
+	no_iotlb_memory[SWIOTLB_LO] = true;
 }
 
 /*
@@ -294,22 +295,22 @@ swiotlb_init(int verbose)
 int
 swiotlb_late_init_with_default_size(size_t default_size)
 {
-	unsigned long bytes, req_nslabs = io_tlb_nslabs;
+	unsigned long bytes, req_nslabs = io_tlb_nslabs[SWIOTLB_LO];
 	unsigned char *vstart = NULL;
 	unsigned int order;
 	int rc = 0;
 
-	if (!io_tlb_nslabs) {
-		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+	if (!io_tlb_nslabs[SWIOTLB_LO]) {
+		io_tlb_nslabs[SWIOTLB_LO] = (default_size >> IO_TLB_SHIFT);
+		io_tlb_nslabs[SWIOTLB_LO] = ALIGN(io_tlb_nslabs[SWIOTLB_LO], IO_TLB_SEGSIZE);
 	}
 
 	/*
 	 * Get IO TLB memory from the low pages
 	 */
-	order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
-	io_tlb_nslabs = SLABS_PER_PAGE << order;
-	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+	order = get_order(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT);
+	io_tlb_nslabs[SWIOTLB_LO] = SLABS_PER_PAGE << order;
+	bytes = io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT;
 
 	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
 		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
@@ -320,15 +321,15 @@ swiotlb_late_init_with_default_size(size_t default_size)
 	}
 
 	if (!vstart) {
-		io_tlb_nslabs = req_nslabs;
+		io_tlb_nslabs[SWIOTLB_LO] = req_nslabs;
 		return -ENOMEM;
 	}
 	if (order != get_order(bytes)) {
 		pr_warn("only able to allocate %ld MB\n",
 			(PAGE_SIZE << order) >> 20);
-		io_tlb_nslabs = SLABS_PER_PAGE << order;
+		io_tlb_nslabs[SWIOTLB_LO] = SLABS_PER_PAGE << order;
 	}
-	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
+	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs[SWIOTLB_LO]);
 	if (rc)
 		free_pages((unsigned long)vstart, order);
 
@@ -337,10 +338,10 @@ swiotlb_late_init_with_default_size(size_t default_size)
 
 static void swiotlb_cleanup(void)
 {
-	io_tlb_end = 0;
-	io_tlb_start = 0;
-	io_tlb_nslabs = 0;
-	max_segment = 0;
+	io_tlb_end[SWIOTLB_LO] = 0;
+	io_tlb_start[SWIOTLB_LO] = 0;
+	io_tlb_nslabs[SWIOTLB_LO] = 0;
+	max_segment[SWIOTLB_LO] = 0;
 }
 
 int
@@ -350,9 +351,9 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 
 	bytes = nslabs << IO_TLB_SHIFT;
 
-	io_tlb_nslabs = nslabs;
-	io_tlb_start = virt_to_phys(tlb);
-	io_tlb_end = io_tlb_start + bytes;
+	io_tlb_nslabs[SWIOTLB_LO] = nslabs;
+	io_tlb_start[SWIOTLB_LO] = virt_to_phys(tlb);
+	io_tlb_end[SWIOTLB_LO] = io_tlb_start[SWIOTLB_LO] + bytes;
 
 	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
 	memset(tlb, 0, bytes);
@@ -362,37 +363,37 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
 	 * between io_tlb_start and io_tlb_end.
 	 */
-	io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
-	                              get_order(io_tlb_nslabs * sizeof(int)));
-	if (!io_tlb_list)
+	io_tlb_list[SWIOTLB_LO] = (unsigned int *)__get_free_pages(GFP_KERNEL,
+			get_order(io_tlb_nslabs[SWIOTLB_LO] * sizeof(int)));
+	if (!io_tlb_list[SWIOTLB_LO])
 		goto cleanup3;
 
-	io_tlb_orig_addr = (phys_addr_t *)
+	io_tlb_orig_addr[SWIOTLB_LO] = (phys_addr_t *)
 		__get_free_pages(GFP_KERNEL,
-				 get_order(io_tlb_nslabs *
+				 get_order(io_tlb_nslabs[SWIOTLB_LO] *
 					   sizeof(phys_addr_t)));
-	if (!io_tlb_orig_addr)
+	if (!io_tlb_orig_addr[SWIOTLB_LO])
 		goto cleanup4;
 
-	for (i = 0; i < io_tlb_nslabs; i++) {
-		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
-		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+	for (i = 0; i < io_tlb_nslabs[SWIOTLB_LO]; i++) {
+		io_tlb_list[SWIOTLB_LO][i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+		io_tlb_orig_addr[SWIOTLB_LO][i] = INVALID_PHYS_ADDR;
 	}
-	io_tlb_index = 0;
-	no_iotlb_memory = false;
+	io_tlb_index[SWIOTLB_LO] = 0;
+	no_iotlb_memory[SWIOTLB_LO] = false;
 
 	swiotlb_print_info();
 
 	late_alloc = 1;
 
-	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+	swiotlb_set_max_segment(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT);
 
 	return 0;
 
 cleanup4:
-	free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
+	free_pages((unsigned long)io_tlb_list[SWIOTLB_LO], get_order(io_tlb_nslabs[SWIOTLB_LO] *
 	                                                 sizeof(int)));
-	io_tlb_list = NULL;
+	io_tlb_list[SWIOTLB_LO] = NULL;
 cleanup3:
 	swiotlb_cleanup();
 	return -ENOMEM;
@@ -400,23 +401,23 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 
 void __init swiotlb_exit(void)
 {
-	if (!io_tlb_orig_addr)
+	if (!io_tlb_orig_addr[SWIOTLB_LO])
 		return;
 
 	if (late_alloc) {
-		free_pages((unsigned long)io_tlb_orig_addr,
-			   get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
-		free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
-								 sizeof(int)));
-		free_pages((unsigned long)phys_to_virt(io_tlb_start),
-			   get_order(io_tlb_nslabs << IO_TLB_SHIFT));
+		free_pages((unsigned long)io_tlb_orig_addr[SWIOTLB_LO],
+			   get_order(io_tlb_nslabs[SWIOTLB_LO] * sizeof(phys_addr_t)));
+		free_pages((unsigned long)io_tlb_list[SWIOTLB_LO],
+			   get_order(io_tlb_nslabs[SWIOTLB_LO] * sizeof(int)));
+		free_pages((unsigned long)phys_to_virt(io_tlb_start[SWIOTLB_LO]),
+			   get_order(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT));
 	} else {
-		memblock_free_late(__pa(io_tlb_orig_addr),
-				   PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
-		memblock_free_late(__pa(io_tlb_list),
-				   PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
-		memblock_free_late(io_tlb_start,
-				   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
+		memblock_free_late(__pa(io_tlb_orig_addr[SWIOTLB_LO]),
+				   PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] * sizeof(phys_addr_t)));
+		memblock_free_late(__pa(io_tlb_list[SWIOTLB_LO]),
+				   PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] * sizeof(int)));
+		memblock_free_late(io_tlb_start[SWIOTLB_LO],
+				   PAGE_ALIGN(io_tlb_nslabs[SWIOTLB_LO] << IO_TLB_SHIFT));
 	}
 	swiotlb_cleanup();
 }
@@ -465,7 +466,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 		size_t mapping_size, size_t alloc_size,
 		enum dma_data_direction dir, unsigned long attrs)
 {
-	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, io_tlb_start);
+	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, io_tlb_start[SWIOTLB_LO]);
 	unsigned long flags;
 	phys_addr_t tlb_addr;
 	unsigned int nslots, stride, index, wrap;
@@ -475,7 +476,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 	unsigned long max_slots;
 	unsigned long tmp_io_tlb_used;
 
-	if (no_iotlb_memory)
+	if (no_iotlb_memory[SWIOTLB_LO])
 		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
 
 	if (mem_encrypt_active())
@@ -518,11 +519,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 	 */
 	spin_lock_irqsave(&io_tlb_lock, flags);
 
-	if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
+	if (unlikely(nslots > io_tlb_nslabs[SWIOTLB_LO] - io_tlb_used[SWIOTLB_LO]))
 		goto not_found;
 
-	index = ALIGN(io_tlb_index, stride);
-	if (index >= io_tlb_nslabs)
+	index = ALIGN(io_tlb_index[SWIOTLB_LO], stride);
+	if (index >= io_tlb_nslabs[SWIOTLB_LO])
 		index = 0;
 	wrap = index;
 
@@ -530,7 +531,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 		while (iommu_is_span_boundary(index, nslots, offset_slots,
 					      max_slots)) {
 			index += stride;
-			if (index >= io_tlb_nslabs)
+			if (index >= io_tlb_nslabs[SWIOTLB_LO])
 				index = 0;
 			if (index == wrap)
 				goto not_found;
@@ -541,39 +542,42 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 		 * contiguous buffers, we allocate the buffers from that slot
 		 * and mark the entries as '0' indicating unavailable.
 		 */
-		if (io_tlb_list[index] >= nslots) {
+		if (io_tlb_list[SWIOTLB_LO][index] >= nslots) {
 			int count = 0;
 
 			for (i = index; i < (int) (index + nslots); i++)
-				io_tlb_list[i] = 0;
-			for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
-				io_tlb_list[i] = ++count;
-			tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
+				io_tlb_list[SWIOTLB_LO][i] = 0;
+			for (i = index - 1;
+			     (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) &&
+			     io_tlb_list[SWIOTLB_LO][i];
+			     i--)
+				io_tlb_list[SWIOTLB_LO][i] = ++count;
+			tlb_addr = io_tlb_start[SWIOTLB_LO] + (index << IO_TLB_SHIFT);
 
 			/*
 			 * Update the indices to avoid searching in the next
 			 * round.
 			 */
-			io_tlb_index = ((index + nslots) < io_tlb_nslabs
+			io_tlb_index[SWIOTLB_LO] = ((index + nslots) < io_tlb_nslabs[SWIOTLB_LO]
 					? (index + nslots) : 0);
 
 			goto found;
 		}
 		index += stride;
-		if (index >= io_tlb_nslabs)
+		if (index >= io_tlb_nslabs[SWIOTLB_LO])
 			index = 0;
 	} while (index != wrap);
 
 not_found:
-	tmp_io_tlb_used = io_tlb_used;
+	tmp_io_tlb_used = io_tlb_used[SWIOTLB_LO];
 
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
 	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
 		dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
-			 alloc_size, io_tlb_nslabs, tmp_io_tlb_used);
+			 alloc_size, io_tlb_nslabs[SWIOTLB_LO], tmp_io_tlb_used);
 	return (phys_addr_t)DMA_MAPPING_ERROR;
 found:
-	io_tlb_used += nslots;
+	io_tlb_used[SWIOTLB_LO] += nslots;
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
 
 	/*
@@ -582,7 +586,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 	 * needed.
 	 */
 	for (i = 0; i < nslots; i++)
-		io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
+		io_tlb_orig_addr[SWIOTLB_LO][index+i] = orig_addr + (i << IO_TLB_SHIFT);
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
 	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
 		swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
@@ -599,8 +603,8 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 {
 	unsigned long flags;
 	int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
-	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-	phys_addr_t orig_addr = io_tlb_orig_addr[index];
+	int index = (tlb_addr - io_tlb_start[SWIOTLB_LO]) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = io_tlb_orig_addr[SWIOTLB_LO][index];
 
 	/*
 	 * First, sync the memory before unmapping the entry
@@ -619,23 +623,26 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 	spin_lock_irqsave(&io_tlb_lock, flags);
 	{
 		count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
-			 io_tlb_list[index + nslots] : 0);
+			 io_tlb_list[SWIOTLB_LO][index + nslots] : 0);
 		/*
 		 * Step 1: return the slots to the free list, merging the
 		 * slots with superceeding slots
 		 */
 		for (i = index + nslots - 1; i >= index; i--) {
-			io_tlb_list[i] = ++count;
-			io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+			io_tlb_list[SWIOTLB_LO][i] = ++count;
+			io_tlb_orig_addr[SWIOTLB_LO][i] = INVALID_PHYS_ADDR;
 		}
 		/*
 		 * Step 2: merge the returned slots with the preceding slots,
 		 * if available (non zero)
 		 */
-		for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
-			io_tlb_list[i] = ++count;
+		for (i = index - 1;
+		     (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) &&
+		     io_tlb_list[SWIOTLB_LO][i];
+		     i--)
+			io_tlb_list[SWIOTLB_LO][i] = ++count;
 
-		io_tlb_used -= nslots;
+		io_tlb_used[SWIOTLB_LO] -= nslots;
 	}
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
 }
@@ -644,8 +651,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
 			     size_t size, enum dma_data_direction dir,
 			     enum dma_sync_target target)
 {
-	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-	phys_addr_t orig_addr = io_tlb_orig_addr[index];
+	int index = (tlb_addr - io_tlb_start[SWIOTLB_LO]) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = io_tlb_orig_addr[SWIOTLB_LO][index];
 
 	if (orig_addr == INVALID_PHYS_ADDR)
 		return;
@@ -716,7 +723,7 @@ bool is_swiotlb_active(void)
 	 * When SWIOTLB is initialized, even if io_tlb_start points to physical
 	 * address zero, io_tlb_end surely doesn't.
 	 */
-	return io_tlb_end != 0;
+	return io_tlb_end[SWIOTLB_LO] != 0;
 }
 
 #ifdef CONFIG_DEBUG_FS
@@ -726,8 +733,8 @@ static int __init swiotlb_create_debugfs(void)
 	struct dentry *root;
 
 	root = debugfs_create_dir("swiotlb", NULL);
-	debugfs_create_ulong("io_tlb_nslabs", 0400, root, &io_tlb_nslabs);
-	debugfs_create_ulong("io_tlb_used", 0400, root, &io_tlb_used);
+	debugfs_create_ulong("io_tlb_nslabs", 0400, root, &io_tlb_nslabs[SWIOTLB_LO]);
+	debugfs_create_ulong("io_tlb_used", 0400, root, &io_tlb_used[SWIOTLB_LO]);
 	return 0;
 }
 
-- 
2.17.1