Commit 8e0629c1 authored by Jan Beulich's avatar Jan Beulich Committed by Konrad Rzeszutek Wilk
Browse files

swiotlb: don't assume PA 0 is invalid 



In 2.6.29 io_tlb_orig_addr[] got converted from storing virtual addresses
to storing physical ones. While checking virtual addresses against NULL
is a legitimate thing to catch invalid entries, checking physical ones
against zero isn't: There's no guarantee that PFN 0 is reserved on a
particular platform.

Since it is unclear whether the check in swiotlb_tbl_unmap_single() is
actually needed, retain it but check against a guaranteed invalid physical
address. This requires setting up the array in a suitable fashion. And
since the original code failed to invalidate array entries when regions
get unmapped, this is being fixed at once along with adding a similar
check to swiotlb_tbl_sync_single().

Obviously the less intrusive change would be to simply drop the check in
swiotlb_tbl_unmap_single().

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 7171511e

lib/swiotlb.c

+18 −10
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ static unsigned int io_tlb_index; 
 * 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;



/*
@@ -188,12 +189,14 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) 
	io_tlb_list = memblock_virt_alloc(

				PAGE_ALIGN(io_tlb_nslabs * sizeof(int)),

				PAGE_SIZE);

	for (i = 0; i < io_tlb_nslabs; i++)

 		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);

	io_tlb_index = 0;

	io_tlb_orig_addr = memblock_virt_alloc(

				PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),

				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;

	}

	io_tlb_index = 0;



	if (verbose)

		swiotlb_print_info();
@@ -313,10 +316,6 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) 
	if (!io_tlb_list)

		goto cleanup3;



	for (i = 0; i < io_tlb_nslabs; i++)

 		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);

	io_tlb_index = 0;



	io_tlb_orig_addr = (phys_addr_t *)

		__get_free_pages(GFP_KERNEL,

				 get_order(io_tlb_nslabs *
@@ -324,7 +323,11 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) 
	if (!io_tlb_orig_addr)

		goto cleanup4;



	memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));

	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;

	}

	io_tlb_index = 0;



	swiotlb_print_info();
@@ -556,7 +559,8 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, 
	/*

	 * First, sync the memory before unmapping the entry

	 */

	if (orig_addr && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))

	if (orig_addr != INVALID_PHYS_ADDR &&

	    ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))

		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);



	/*
@@ -573,8 +577,10 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, 
		 * Step 1: return the slots to the free list, merging the

		 * slots with superceeding slots

		 */

		for (i = index + nslots - 1; i >= index; i--)

		for (i = index + nslots - 1; i >= index; i--) {

			io_tlb_list[i] = ++count;

			io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;

		}

		/*

		 * Step 2: merge the returned slots with the preceding slots,

		 * if available (non zero)
@@ -593,6 +599,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, 
	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;

	phys_addr_t orig_addr = io_tlb_orig_addr[index];



	if (orig_addr == INVALID_PHYS_ADDR)

		return;

	orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);



	switch (target) {

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