FAILED: patch "[PATCH] swiotlb: manipulate orig_addr when tlb_addr has offset" failed to apply to 5.10-stable tree
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[email protected]
maintainerThe patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5f89468e2f060031cd89fd4287298e0eaf246bf6 Mon Sep 17 00:00:00 2001
From: Bumyong Lee <[email protected]>
Date: Mon, 10 May 2021 18:10:04 +0900
Subject: [PATCH] swiotlb: manipulate orig_addr when tlb_addr has offset
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in case of driver wants to sync part of ranges with offset, swiotlb_tbl_sync_single() copies from orig_addr base to tlb_addr with offset and ends up with data mismatch.
It was removed from
"swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single", but said logic has to be added back in.
From Linus's email:
"That commit which the removed the offset calculation entirely, because the old
(unsigned long)tlb_addr & (IO_TLB_SIZE - 1)
was wrong, but instead of removing it, I think it should have just fixed it to be
(tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
instead. That way the slot offset always matches the slot index calculation."
(Unfortunatly that broke NVMe).
The use-case that drivers are hitting is as follow:
1. Get dma_addr_t from dma_map_single()
dma_addr_t tlb_addr = dma_map_single(dev, vaddr, vsize, DMA_TO_DEVICE);
|<---------------vsize------------->|
+-----------------------------------+
| | original buffer
+-----------------------------------+vaddr
swiotlb_align_offset
|<----->|<---------------vsize------------->|
+-------+-----------------------------------+
| | | swiotlb buffer
+-------+-----------------------------------+ tlb_addr
2. Do something
3. Sync dma_addr_t through dma_sync_single_for_device(..)
dma_sync_single_for_device(dev, tlb_addr + offset, size, DMA_TO_DEVICE);
Error case.
Copy data to original buffer but it is from base addr (instead of
base addr + offset) in original buffer:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- size ->|
+-----------------------------------+
|##########| | original buffer
+-----------------------------------+vaddr
The fix is to copy the data to the original buffer and take into account the offset, like so:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- offset ->|<- size ->|
+-----------------------------------+
| |##########| | original buffer
+-----------------------------------+vaddr
[One fix which was Linus's that made more sense to as it created a symmetry would break NVMe. The reason for that is the:
unsigned int offset = (tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
would come up with the proper offset, but it would lose the alignment (which this patch contains).]
kernel/dma/swiotlb.c +15 -8
@@ -334,6 +334,14 @@ void __init swiotlb_exit(void) io_tlb_default_mem =NULL ; } +/* +* Return the offset into a iotlb slot required to keep the device happy. +*/ +static unsigned int swiotlb_align_offset (struct device *dev,u64 addr) +{ +return addr &dma_get_min_align_mask (dev) & (IO_TLB_SIZE -1 ); +} +/* * Bounce: copy the swiotlb buffer from or back to the original dma location */
@@ -346,10 +354,17 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t sizesize_t alloc_size = mem->slots[index].alloc_size;unsigned long pfn =PFN_DOWN (orig_addr);unsigned char *vaddr =phys_to_virt (tlb_addr); +unsigned int tlb_offset;if (orig_addr ==INVALID_PHYS_ADDR )return ; + tlb_offset = (tlb_addr & (IO_TLB_SIZE -1 )) - +swiotlb_align_offset (dev, orig_addr); + + orig_addr += tlb_offset; + alloc_size -= tlb_offset; +if (size > alloc_size) { dev_WARN_ONCE(dev, 1, "Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
@@ -390,14 +405,6 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size#define slot_addr (start, idx) ((start) + ((idx) << IO_TLB_SHIFT)) -/* -* Return the offset into a iotlb slot required to keep the device happy. -*/ -static unsigned int swiotlb_align_offset (struct device *dev,u64 addr) -{ -return addr &dma_get_min_align_mask (dev) & (IO_TLB_SIZE -1 ); -} -/* * Carefully handle integer overflow which can occur when boundary_mask == ~0UL. */
PATCH 1/1 swiotlb: manipulate orig_addr when tlb_addr has offset
From: Bumyong Lee <[email protected]>
commit 5f89468e2f060031cd89fd4287298e0eaf246bf6 upstream. (Backported as different form due to absence of below patch series
https://lore.kernel.org/linux-iommu/[email protected]/)
in case of driver wants to sync part of ranges with offset, swiotlb_tbl_sync_single() copies from orig_addr base to tlb_addr with offset and ends up with data mismatch.
It was removed from
"swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single", but said logic has to be added back in.
From Linus's email:
"That commit which the removed the offset calculation entirely, because the old
(unsigned long)tlb_addr & (IO_TLB_SIZE - 1)
was wrong, but instead of removing it, I think it should have just fixed it to be
(tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
instead. That way the slot offset always matches the slot index calculation."
(Unfortunatly that broke NVMe).
The use-case that drivers are hitting is as follow:
1. Get dma_addr_t from dma_map_single()
dma_addr_t tlb_addr = dma_map_single(dev, vaddr, vsize, DMA_TO_DEVICE);
|<---------------vsize------------->|
+-----------------------------------+
| | original buffer
+-----------------------------------+vaddr
swiotlb_align_offset
|<----->|<---------------vsize------------->|
+-------+-----------------------------------+
| | | swiotlb buffer
+-------+-----------------------------------+ tlb_addr
2. Do something
3. Sync dma_addr_t through dma_sync_single_for_device(..)
dma_sync_single_for_device(dev, tlb_addr + offset, size, DMA_TO_DEVICE);
Error case.
Copy data to original buffer but it is from base addr (instead of
base addr + offset) in original buffer:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- size ->|
+-----------------------------------+
|##########| | original buffer
+-----------------------------------+vaddr
The fix is to copy the data to the original buffer and take into account the offset, like so:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- offset ->|<- size ->|
+-----------------------------------+
| |##########| | original buffer
+-----------------------------------+vaddr
[One fix which was Linus's that made more sense to as it created a symmetry would break NVMe. The reason for that is the:
unsigned int offset = (tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
would come up with the proper offset, but it would lose the alignment (which this patch contains).]
--- kernel/dma/swiotlb.c | 3 +++ 1 file changed, 3 insertions(+)
kernel/dma/swiotlb.c +3 -0
@@ -667,6 +667,9 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,if (orig_addr ==INVALID_PHYS_ADDR )return ; + orig_addr += (tlb_addr & (IO_TLB_SIZE -1 )) - +swiotlb_align_offset (hwdev, orig_addr); +switch (target) {case SYNC_FOR_CPU :if (likely (dir ==DMA_FROM_DEVICE || dir ==DMA_BIDIRECTIONAL ))
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2.32.0