[PATCH v9 07/14] swiotlb: Bounce data from/to restricted DMA pool if available
From: Claire Chang <hidden>
Date: 2021-06-11 15:29:45
Also in:
dri-devel, intel-gfx, linux-devicetree, linux-iommu, linux-pci, lkml, xen-devel
Subsystem:
dma mapping helpers, the rest · Maintainers:
Marek Szyprowski, Linus Torvalds
Regardless of swiotlb setting, the restricted DMA pool is preferred if
available.
The restricted DMA pools provide a basic level of protection against the
DMA overwriting buffer contents at unexpected times. However, to protect
against general data leakage and system memory corruption, the system
needs to provide a way to lock down the memory access, e.g., MPU.
Note that is_dev_swiotlb_force doesn't check if
swiotlb_force == SWIOTLB_FORCE. Otherwise the memory allocation behavior
with default swiotlb will be changed by the following patche
("dma-direct: Allocate memory from restricted DMA pool if available").
Signed-off-by: Claire Chang <redacted>
---
include/linux/swiotlb.h | 10 +++++++++-
kernel/dma/direct.c | 3 ++-
kernel/dma/direct.h | 3 ++-
kernel/dma/swiotlb.c | 1 +
4 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 06cf17a80f5c..8200c100fe10 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h@@ -85,6 +85,7 @@ extern enum swiotlb_force swiotlb_force; * unmap calls. * @debugfs: The dentry to debugfs. * @late_alloc: %true if allocated using the page allocator + * @force_swiotlb: %true if swiotlb is forced */ struct io_tlb_mem { phys_addr_t start;
@@ -95,6 +96,7 @@ struct io_tlb_mem { spinlock_t lock; struct dentry *debugfs; bool late_alloc; + bool force_swiotlb; struct io_tlb_slot { phys_addr_t orig_addr; size_t alloc_size;
@@ -115,6 +117,11 @@ static inline void swiotlb_set_io_tlb_default_mem(struct device *dev) dev->dma_io_tlb_mem = io_tlb_default_mem; } +static inline bool is_dev_swiotlb_force(struct device *dev) +{ + return dev->dma_io_tlb_mem->force_swiotlb; +} + void __init swiotlb_exit(void); unsigned int swiotlb_max_segment(void); size_t swiotlb_max_mapping_size(struct device *dev);
@@ -126,8 +133,9 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr) { return false; } -static inline void swiotlb_set_io_tlb_default_mem(struct device *dev) +static inline bool is_dev_swiotlb_force(struct device *dev) { + return false; } static inline void swiotlb_exit(void) {
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 7a88c34d0867..078f7087e466 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c@@ -496,7 +496,8 @@ size_t dma_direct_max_mapping_size(struct device *dev) { /* If SWIOTLB is active, use its maximum mapping size */ if (is_swiotlb_active(dev) && - (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE)) + (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE || + is_dev_swiotlb_force(dev))) return swiotlb_max_mapping_size(dev); return SIZE_MAX; }
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index 13e9e7158d94..f94813674e23 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h@@ -87,7 +87,8 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys); - if (unlikely(swiotlb_force == SWIOTLB_FORCE)) + if (unlikely(swiotlb_force == SWIOTLB_FORCE) || + is_dev_swiotlb_force(dev)) return swiotlb_map(dev, phys, size, dir, attrs); if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 21e99907edd6..e5ccc198d0a7 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c@@ -714,6 +714,7 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem, return -ENOMEM; swiotlb_init_io_tlb_mem(mem, rmem->base, nslabs, false, true); + mem->force_swiotlb = true; rmem->priv = mem;
--
2.32.0.272.g935e593368-goog