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* [PATCH v4 00/14] Restricted DMA
@ 2021-02-09  6:21 Claire Chang
  2021-02-09  6:21 ` [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start Claire Chang
                   ` (14 more replies)
  0 siblings, 15 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

This series implements mitigations for lack of DMA access control on
systems without an IOMMU, which could result in the DMA accessing the
system memory at unexpected times and/or unexpected addresses, possibly
leading to data leakage or corruption.

For example, we plan to use the PCI-e bus for Wi-Fi and that PCI-e bus is
not behind an IOMMU. As PCI-e, by design, gives the device full access to
system memory, a vulnerability in the Wi-Fi firmware could easily escalate
to a full system exploit (remote wifi exploits: [1a], [1b] that shows a
full chain of exploits; [2], [3]).

To mitigate the security concerns, we introduce restricted DMA. Restricted
DMA utilizes the existing swiotlb to bounce streaming DMA in and out of a
specially allocated region and does memory allocation from the same region.
The feature on its own provides 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 restrict the DMA to a predefined memory region (this is
usually done at firmware level, e.g. MPU in ATF on some ARM platforms [4]).

[1a] https://googleprojectzero.blogspot.com/2017/04/over-air-exploiting-broadcoms-wi-fi_4.html
[1b] https://googleprojectzero.blogspot.com/2017/04/over-air-exploiting-broadcoms-wi-fi_11.html
[2] https://blade.tencent.com/en/advisories/qualpwn/
[3] https://www.bleepingcomputer.com/news/security/vulnerabilities-found-in-highly-popular-firmware-for-wifi-chips/
[4] https://github.com/ARM-software/arm-trusted-firmware/blob/master/plat/mediatek/mt8183/drivers/emi_mpu/emi_mpu.c#L132

Claire Chang (14):
  swiotlb: Remove external access to io_tlb_start
  swiotlb: Move is_swiotlb_buffer() to swiotlb.c
  swiotlb: Add struct swiotlb
  swiotlb: Refactor swiotlb_late_init_with_tbl
  swiotlb: Add DMA_RESTRICTED_POOL
  swiotlb: Add restricted DMA pool
  swiotlb: Update swiotlb API to gain a struct device argument
  swiotlb: Use restricted DMA pool if available
  swiotlb: Refactor swiotlb_tbl_{map,unmap}_single
  dma-direct: Add a new wrapper __dma_direct_free_pages()
  swiotlb: Add is_dev_swiotlb_force()
  swiotlb: Add restricted DMA alloc/free support.
  dt-bindings: of: Add restricted DMA pool
  of: Add plumbing for restricted DMA pool

 .../reserved-memory/reserved-memory.txt       |  24 +
 arch/powerpc/platforms/pseries/svm.c          |   4 +-
 drivers/iommu/dma-iommu.c                     |  12 +-
 drivers/of/address.c                          |  25 +
 drivers/of/device.c                           |   3 +
 drivers/of/of_private.h                       |   5 +
 drivers/xen/swiotlb-xen.c                     |   4 +-
 include/linux/device.h                        |   4 +
 include/linux/swiotlb.h                       |  32 +-
 kernel/dma/Kconfig                            |  14 +
 kernel/dma/direct.c                           |  51 +-
 kernel/dma/direct.h                           |   8 +-
 kernel/dma/swiotlb.c                          | 636 ++++++++++++------
 13 files changed, 582 insertions(+), 240 deletions(-)

-- 

v4:
  - Fix spinlock bad magic
  - Use rmem->name for debugfs entry
  - Address the comments in v3

v3:
  Using only one reserved memory region for both streaming DMA and memory
  allocation.
  https://lore.kernel.org/patchwork/cover/1360992/

v2:
  Building on top of swiotlb.
  https://lore.kernel.org/patchwork/cover/1280705/

v1:
  Using dma_map_ops.
  https://lore.kernel.org/patchwork/cover/1271660/

2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  8:40   ` Christoph Hellwig
  2021-02-09  6:21 ` [PATCH v4 02/14] swiotlb: Move is_swiotlb_buffer() to swiotlb.c Claire Chang
                   ` (13 subsequent siblings)
  14 siblings, 1 reply; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Add a new function, get_swiotlb_start(), and remove external access to
io_tlb_start, so we can entirely hide struct swiotlb inside of swiotlb.c
in the following patches.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 arch/powerpc/platforms/pseries/svm.c | 4 ++--
 drivers/xen/swiotlb-xen.c            | 4 ++--
 include/linux/swiotlb.h              | 1 +
 kernel/dma/swiotlb.c                 | 5 +++++
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index 7b739cc7a8a9..c10c51d49f3d 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -55,8 +55,8 @@ 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,
+	if (vstart)
+		memblock_free_early(vstart,
 				    PAGE_ALIGN(io_tlb_nslabs << 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..91f8c68d1a9b 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 (is_swiotlb_active()) {
+		xen_io_tlb_start = phys_to_virt(get_swiotlb_start());
 		goto end;
 	}
 
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index d9c9fc9ca5d2..83200f3b042a 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -81,6 +81,7 @@ void __init swiotlb_exit(void);
 unsigned int swiotlb_max_segment(void);
 size_t swiotlb_max_mapping_size(struct device *dev);
 bool is_swiotlb_active(void);
+phys_addr_t get_swiotlb_start(void);
 void __init swiotlb_adjust_size(unsigned long new_size);
 #else
 #define swiotlb_force SWIOTLB_NO_FORCE
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 7c42df6e6100..e180211f6ad9 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -719,6 +719,11 @@ bool is_swiotlb_active(void)
 	return io_tlb_end != 0;
 }
 
+phys_addr_t get_swiotlb_start(void)
+{
+	return io_tlb_start;
+}
+
 #ifdef CONFIG_DEBUG_FS
 
 static int __init swiotlb_create_debugfs(void)
--

This can be dropped if Christoph's swiotlb cleanups are landed.
https://lore.kernel.org/linux-iommu/20210207160934.2955931-1-hch@lst.de/T/#m7124f29b6076d462101fcff6433295157621da09 

2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 02/14] swiotlb: Move is_swiotlb_buffer() to swiotlb.c
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
  2021-02-09  6:21 ` [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 03/14] swiotlb: Add struct swiotlb Claire Chang
                   ` (12 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Move is_swiotlb_buffer() to swiotlb.c and make io_tlb_{start,end}
static, so we can entirely hide struct swiotlb inside of swiotlb.c in
the following patches.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h | 7 +------
 kernel/dma/swiotlb.c    | 7 ++++++-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 83200f3b042a..041611bf3c2a 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -70,13 +70,8 @@ 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;
-
-static inline bool is_swiotlb_buffer(phys_addr_t paddr)
-{
-	return paddr >= io_tlb_start && paddr < io_tlb_end;
-}
 
+bool is_swiotlb_buffer(phys_addr_t paddr);
 void __init swiotlb_exit(void);
 unsigned int swiotlb_max_segment(void);
 size_t swiotlb_max_mapping_size(struct device *dev);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index e180211f6ad9..678490d39e55 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -69,7 +69,7 @@ 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;
+static phys_addr_t io_tlb_start, io_tlb_end;
 
 /*
  * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
@@ -719,6 +719,11 @@ bool is_swiotlb_active(void)
 	return io_tlb_end != 0;
 }
 
+bool is_swiotlb_buffer(phys_addr_t paddr)
+{
+	return paddr >= io_tlb_start && paddr < io_tlb_end;
+}
+
 phys_addr_t get_swiotlb_start(void)
 {
 	return io_tlb_start;
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 03/14] swiotlb: Add struct swiotlb
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
  2021-02-09  6:21 ` [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start Claire Chang
  2021-02-09  6:21 ` [PATCH v4 02/14] swiotlb: Move is_swiotlb_buffer() to swiotlb.c Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 04/14] swiotlb: Refactor swiotlb_late_init_with_tbl Claire Chang
                   ` (11 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Added a new struct, swiotlb, as the IO TLB memory pool descriptor and
moved relevant global variables into that struct.
This will be useful later to allow for restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 kernel/dma/swiotlb.c | 327 +++++++++++++++++++++++--------------------
 1 file changed, 172 insertions(+), 155 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 678490d39e55..28b7bfe7a2a8 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -61,33 +61,43 @@
  * allocate a contiguous 1MB, we're probably in trouble anyway.
  */
 #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
+#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
 
 enum swiotlb_force swiotlb_force;
 
 /*
- * Used to do a quick range check in swiotlb_tbl_unmap_single and
- * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
- * API.
- */
-static phys_addr_t io_tlb_start, io_tlb_end;
-
-/*
- * 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;
-
-/*
- * The number of used IO TLB block
- */
-static unsigned long io_tlb_used;
-
-/*
- * This is a free list describing the number of free entries available from
- * each index
+ * struct swiotlb - Software IO TLB Memory Pool Descriptor
+ *
+ * @start:      The start address of the swiotlb memory pool. Used to do a quick
+ *              range check to see if the memory was in fact allocated by this
+ *              API.
+ * @end:        The end address of the swiotlb memory pool. Used to do a quick
+ *              range check to see if the memory was in fact allocated by this
+ *              API.
+ * @nslabs:     The number of IO TLB blocks (in groups of 64) between @start and
+ *              @end. This is command line adjustable via setup_io_tlb_npages.
+ * @used:       The number of used IO TLB block.
+ * @list:       The free list describing the number of free entries available
+ *              from each index.
+ * @index:      The index to start searching in the next round.
+ * @orig_addr:  The original address corresponding to a mapped entry for the
+ *              sync operations.
+ * @lock:       The lock to protect the above data structures in the map and
+ *              unmap calls.
+ * @debugfs:    The dentry to debugfs.
  */
-static unsigned int *io_tlb_list;
-static unsigned int io_tlb_index;
+struct swiotlb {
+	phys_addr_t start;
+	phys_addr_t end;
+	unsigned long nslabs;
+	unsigned long used;
+	unsigned int *list;
+	unsigned int index;
+	phys_addr_t *orig_addr;
+	spinlock_t lock;
+	struct dentry *debugfs;
+};
+static struct swiotlb default_swiotlb;
 
 /*
  * Max segment that we can provide which (if pages are contingous) will
@@ -95,27 +105,17 @@ static unsigned int io_tlb_index;
  */
 static unsigned int max_segment;
 
-/*
- * 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;
-
-/*
- * Protect the above data structures in the map and unmap calls
- */
-static DEFINE_SPINLOCK(io_tlb_lock);
-
 static int late_alloc;
 
 static int __init
 setup_io_tlb_npages(char *str)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
+
 	if (isdigit(*str)) {
-		io_tlb_nslabs = simple_strtoul(str, &str, 0);
+		swiotlb->nslabs = simple_strtoul(str, &str, 0);
 		/* avoid tail segment of size < IO_TLB_SEGSIZE */
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+		swiotlb->nslabs = ALIGN(swiotlb->nslabs, IO_TLB_SEGSIZE);
 	}
 	if (*str == ',')
 		++str;
@@ -123,7 +123,7 @@ setup_io_tlb_npages(char *str)
 		swiotlb_force = SWIOTLB_FORCE;
 	} else if (!strcmp(str, "noforce")) {
 		swiotlb_force = SWIOTLB_NO_FORCE;
-		io_tlb_nslabs = 1;
+		swiotlb->nslabs = 1;
 	}
 
 	return 0;
@@ -134,7 +134,7 @@ static bool no_iotlb_memory;
 
 unsigned long swiotlb_nr_tbl(void)
 {
-	return unlikely(no_iotlb_memory) ? 0 : io_tlb_nslabs;
+	return unlikely(no_iotlb_memory) ? 0 : default_swiotlb.nslabs;
 }
 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
 
@@ -156,13 +156,14 @@ unsigned long swiotlb_size_or_default(void)
 {
 	unsigned long size;
 
-	size = io_tlb_nslabs << IO_TLB_SHIFT;
+	size = default_swiotlb.nslabs << IO_TLB_SHIFT;
 
 	return size ? size : (IO_TLB_DEFAULT_SIZE);
 }
 
 void __init swiotlb_adjust_size(unsigned long new_size)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
 	unsigned long size;
 
 	/*
@@ -170,10 +171,10 @@ 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 (!swiotlb->nslabs) {
 		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);
+		swiotlb->nslabs = size >> IO_TLB_SHIFT;
+		swiotlb->nslabs = ALIGN(swiotlb->nslabs, IO_TLB_SEGSIZE);
 
 		pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20);
 	}
@@ -181,14 +182,15 @@ void __init swiotlb_adjust_size(unsigned long new_size)
 
 void swiotlb_print_info(void)
 {
-	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+	struct swiotlb *swiotlb = &default_swiotlb;
+	unsigned long bytes = swiotlb->nslabs << IO_TLB_SHIFT;
 
 	if (no_iotlb_memory) {
 		pr_warn("No low mem\n");
 		return;
 	}
 
-	pr_info("mapped [mem %pa-%pa] (%luMB)\n", &io_tlb_start, &io_tlb_end,
+	pr_info("mapped [mem %pa-%pa] (%luMB)\n", &swiotlb->start, &swiotlb->end,
 	       bytes >> 20);
 }
 
@@ -200,57 +202,61 @@ void swiotlb_print_info(void)
  */
 void __init swiotlb_update_mem_attributes(void)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
 	void *vaddr;
 	unsigned long bytes;
 
 	if (no_iotlb_memory || late_alloc)
 		return;
 
-	vaddr = phys_to_virt(io_tlb_start);
-	bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
+	vaddr = phys_to_virt(swiotlb->start);
+	bytes = PAGE_ALIGN(swiotlb->nslabs << IO_TLB_SHIFT);
 	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
 	memset(vaddr, 0, bytes);
 }
 
 int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
 	unsigned long i, bytes;
 	size_t alloc_size;
 
 	bytes = nslabs << IO_TLB_SHIFT;
 
-	io_tlb_nslabs = nslabs;
-	io_tlb_start = __pa(tlb);
-	io_tlb_end = io_tlb_start + bytes;
+	swiotlb->nslabs = nslabs;
+	swiotlb->start = __pa(tlb);
+	swiotlb->end = swiotlb->start + 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.
+	 * between swiotlb->start and swiotlb->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(swiotlb->nslabs * sizeof(int));
+	swiotlb->list = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!swiotlb->list)
 		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(swiotlb->nslabs * sizeof(phys_addr_t));
+	swiotlb->orig_addr = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!swiotlb->orig_addr)
 		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 < swiotlb->nslabs; i++) {
+		swiotlb->list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+		swiotlb->orig_addr[i] = INVALID_PHYS_ADDR;
 	}
-	io_tlb_index = 0;
+	swiotlb->index = 0;
 	no_iotlb_memory = false;
 
 	if (verbose)
 		swiotlb_print_info();
 
-	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+	swiotlb_set_max_segment(swiotlb->nslabs << IO_TLB_SHIFT);
+	spin_lock_init(&swiotlb->lock);
+
 	return 0;
 }
 
@@ -261,26 +267,27 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 void  __init
 swiotlb_init(int verbose)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
 	size_t default_size = IO_TLB_DEFAULT_SIZE;
 	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 (!swiotlb->nslabs) {
+		swiotlb->nslabs = (default_size >> IO_TLB_SHIFT);
+		swiotlb->nslabs = ALIGN(swiotlb->nslabs, IO_TLB_SEGSIZE);
 	}
 
-	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+	bytes = swiotlb->nslabs << 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, swiotlb->nslabs, 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 (swiotlb->start) {
+		memblock_free_early(swiotlb->start,
+				    PAGE_ALIGN(swiotlb->nslabs << IO_TLB_SHIFT));
+		swiotlb->start = 0;
 	}
 	pr_warn("Cannot allocate buffer");
 	no_iotlb_memory = true;
@@ -294,22 +301,23 @@ swiotlb_init(int verbose)
 int
 swiotlb_late_init_with_default_size(size_t default_size)
 {
-	unsigned long bytes, req_nslabs = io_tlb_nslabs;
+	struct swiotlb *swiotlb = &default_swiotlb;
+	unsigned long bytes, req_nslabs = swiotlb->nslabs;
 	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 (!swiotlb->nslabs) {
+		swiotlb->nslabs = (default_size >> IO_TLB_SHIFT);
+		swiotlb->nslabs = ALIGN(swiotlb->nslabs, 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(swiotlb->nslabs << IO_TLB_SHIFT);
+	swiotlb->nslabs = SLABS_PER_PAGE << order;
+	bytes = swiotlb->nslabs << IO_TLB_SHIFT;
 
 	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
 		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
@@ -320,15 +328,15 @@ swiotlb_late_init_with_default_size(size_t default_size)
 	}
 
 	if (!vstart) {
-		io_tlb_nslabs = req_nslabs;
+		swiotlb->nslabs = 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;
+		swiotlb->nslabs = SLABS_PER_PAGE << order;
 	}
-	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
+	rc = swiotlb_late_init_with_tbl(vstart, swiotlb->nslabs);
 	if (rc)
 		free_pages((unsigned long)vstart, order);
 
@@ -337,22 +345,25 @@ 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;
+	struct swiotlb *swiotlb = &default_swiotlb;
+
+	swiotlb->end = 0;
+	swiotlb->start = 0;
+	swiotlb->nslabs = 0;
 	max_segment = 0;
 }
 
 int
 swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
 	unsigned long i, bytes;
 
 	bytes = nslabs << IO_TLB_SHIFT;
 
-	io_tlb_nslabs = nslabs;
-	io_tlb_start = virt_to_phys(tlb);
-	io_tlb_end = io_tlb_start + bytes;
+	swiotlb->nslabs = nslabs;
+	swiotlb->start = virt_to_phys(tlb);
+	swiotlb->end = swiotlb->start + bytes;
 
 	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
 	memset(tlb, 0, bytes);
@@ -360,39 +371,40 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	/*
 	 * 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.
+	 * between swiotlb->start and swiotlb->end.
 	 */
-	io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
-	                              get_order(io_tlb_nslabs * sizeof(int)));
-	if (!io_tlb_list)
+	swiotlb->list = (unsigned int *)__get_free_pages(GFP_KERNEL,
+	                              get_order(swiotlb->nslabs * sizeof(int)));
+	if (!swiotlb->list)
 		goto cleanup3;
 
-	io_tlb_orig_addr = (phys_addr_t *)
+	swiotlb->orig_addr = (phys_addr_t *)
 		__get_free_pages(GFP_KERNEL,
-				 get_order(io_tlb_nslabs *
+				 get_order(swiotlb->nslabs *
 					   sizeof(phys_addr_t)));
-	if (!io_tlb_orig_addr)
+	if (!swiotlb->orig_addr)
 		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 < swiotlb->nslabs; i++) {
+		swiotlb->list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+		swiotlb->orig_addr[i] = INVALID_PHYS_ADDR;
 	}
-	io_tlb_index = 0;
+	swiotlb->index = 0;
 	no_iotlb_memory = false;
 
 	swiotlb_print_info();
 
 	late_alloc = 1;
 
-	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+	swiotlb_set_max_segment(swiotlb->nslabs << IO_TLB_SHIFT);
+	spin_lock_init(&swiotlb->lock);
 
 	return 0;
 
 cleanup4:
-	free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
-	                                                 sizeof(int)));
-	io_tlb_list = NULL;
+	free_pages((unsigned long)swiotlb->list,
+		   get_order(swiotlb->nslabs * sizeof(int)));
+	swiotlb->list = NULL;
 cleanup3:
 	swiotlb_cleanup();
 	return -ENOMEM;
@@ -400,23 +412,25 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 
 void __init swiotlb_exit(void)
 {
-	if (!io_tlb_orig_addr)
+	struct swiotlb *swiotlb = &default_swiotlb;
+
+	if (!swiotlb->orig_addr)
 		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)swiotlb->orig_addr,
+			   get_order(swiotlb->nslabs * sizeof(phys_addr_t)));
+		free_pages((unsigned long)swiotlb->list,
+			   get_order(swiotlb->nslabs * sizeof(int)));
+		free_pages((unsigned long)phys_to_virt(swiotlb->start),
+			   get_order(swiotlb->nslabs << 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(swiotlb->orig_addr),
+				   PAGE_ALIGN(swiotlb->nslabs * sizeof(phys_addr_t)));
+		memblock_free_late(__pa(swiotlb->list),
+				   PAGE_ALIGN(swiotlb->nslabs * sizeof(int)));
+		memblock_free_late(swiotlb->start,
+				   PAGE_ALIGN(swiotlb->nslabs << IO_TLB_SHIFT));
 	}
 	swiotlb_cleanup();
 }
@@ -465,7 +479,8 @@ 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);
+	struct swiotlb *swiotlb = &default_swiotlb;
+	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, swiotlb->start);
 	unsigned long flags;
 	phys_addr_t tlb_addr;
 	unsigned int nslots, stride, index, wrap;
@@ -516,13 +531,13 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 	 * Find suitable number of IO TLB entries size that will fit this
 	 * request and allocate a buffer from that IO TLB pool.
 	 */
-	spin_lock_irqsave(&io_tlb_lock, flags);
+	spin_lock_irqsave(&swiotlb->lock, flags);
 
-	if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
+	if (unlikely(nslots > swiotlb->nslabs - swiotlb->used))
 		goto not_found;
 
-	index = ALIGN(io_tlb_index, stride);
-	if (index >= io_tlb_nslabs)
+	index = ALIGN(swiotlb->index, stride);
+	if (index >= swiotlb->nslabs)
 		index = 0;
 	wrap = index;
 
@@ -530,7 +545,7 @@ 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 >= swiotlb->nslabs)
 				index = 0;
 			if (index == wrap)
 				goto not_found;
@@ -541,40 +556,40 @@ 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 (swiotlb->list[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);
+				swiotlb->list[i] = 0;
+			for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && swiotlb->list[i]; i--)
+				swiotlb->list[i] = ++count;
+			tlb_addr = swiotlb->start + (index << IO_TLB_SHIFT);
 
 			/*
 			 * Update the indices to avoid searching in the next
 			 * round.
 			 */
-			io_tlb_index = ((index + nslots) < io_tlb_nslabs
-					? (index + nslots) : 0);
+			swiotlb->index = ((index + nslots) < swiotlb->nslabs
+				      ? (index + nslots) : 0);
 
 			goto found;
 		}
 		index += stride;
-		if (index >= io_tlb_nslabs)
+		if (index >= swiotlb->nslabs)
 			index = 0;
 	} while (index != wrap);
 
 not_found:
-	tmp_io_tlb_used = io_tlb_used;
+	tmp_io_tlb_used = swiotlb->used;
 
-	spin_unlock_irqrestore(&io_tlb_lock, flags);
+	spin_unlock_irqrestore(&swiotlb->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, swiotlb->nslabs, tmp_io_tlb_used);
 	return (phys_addr_t)DMA_MAPPING_ERROR;
 found:
-	io_tlb_used += nslots;
-	spin_unlock_irqrestore(&io_tlb_lock, flags);
+	swiotlb->used += nslots;
+	spin_unlock_irqrestore(&swiotlb->lock, flags);
 
 	/*
 	 * Save away the mapping from the original address to the DMA address.
@@ -582,7 +597,7 @@ 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);
+		swiotlb->orig_addr[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);
@@ -597,10 +612,11 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 			      size_t mapping_size, size_t alloc_size,
 			      enum dma_data_direction dir, unsigned long attrs)
 {
+	struct swiotlb *swiotlb = &default_swiotlb;
 	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 - swiotlb->start) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = swiotlb->orig_addr[index];
 
 	/*
 	 * First, sync the memory before unmapping the entry
@@ -616,36 +632,37 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 	 * While returning the entries to the free list, we merge the entries
 	 * with slots below and above the pool being returned.
 	 */
-	spin_lock_irqsave(&io_tlb_lock, flags);
+	spin_lock_irqsave(&swiotlb->lock, flags);
 	{
 		count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
-			 io_tlb_list[index + nslots] : 0);
+			 swiotlb->list[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;
+			swiotlb->list[i] = ++count;
+			swiotlb->orig_addr[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) && swiotlb->list[i]; i--)
+			swiotlb->list[i] = ++count;
 
-		io_tlb_used -= nslots;
+		swiotlb->used -= nslots;
 	}
-	spin_unlock_irqrestore(&io_tlb_lock, flags);
+	spin_unlock_irqrestore(&swiotlb->lock, flags);
 }
 
 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];
+	struct swiotlb *swiotlb = &default_swiotlb;
+	int index = (tlb_addr - swiotlb->start) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = swiotlb->orig_addr[index];
 
 	if (orig_addr == INVALID_PHYS_ADDR)
 		return;
@@ -713,31 +730,31 @@ size_t swiotlb_max_mapping_size(struct device *dev)
 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.
+	 * When SWIOTLB is initialized, even if swiotlb->start points to
+	 * physical address zero, swiotlb->end surely doesn't.
 	 */
-	return io_tlb_end != 0;
+	return default_swiotlb.end != 0;
 }
 
 bool is_swiotlb_buffer(phys_addr_t paddr)
 {
-	return paddr >= io_tlb_start && paddr < io_tlb_end;
+	return paddr >= default_swiotlb.start && paddr < default_swiotlb.end;
 }
 
 phys_addr_t get_swiotlb_start(void)
 {
-	return io_tlb_start;
+	return default_swiotlb.start;
 }
 
 #ifdef CONFIG_DEBUG_FS
 
 static int __init swiotlb_create_debugfs(void)
 {
-	struct dentry *root;
+	struct swiotlb *swiotlb = &default_swiotlb;
 
-	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);
+	swiotlb->debugfs = debugfs_create_dir("swiotlb", NULL);
+	debugfs_create_ulong("io_tlb_nslabs", 0400, swiotlb->debugfs, &swiotlb->nslabs);
+	debugfs_create_ulong("io_tlb_used", 0400, swiotlb->debugfs, &swiotlb->used);
 	return 0;
 }
 
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 04/14] swiotlb: Refactor swiotlb_late_init_with_tbl
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (2 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 03/14] swiotlb: Add struct swiotlb Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 05/14] swiotlb: Add DMA_RESTRICTED_POOL Claire Chang
                   ` (10 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Refactor swiotlb_late_init_with_tbl to make the code reusable for
restricted DMA pool initialization.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 kernel/dma/swiotlb.c | 65 ++++++++++++++++++++++++++++----------------
 1 file changed, 42 insertions(+), 23 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 28b7bfe7a2a8..dc37951c6924 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -353,20 +353,21 @@ static void swiotlb_cleanup(void)
 	max_segment = 0;
 }
 
-int
-swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
+static int swiotlb_init_tlb_pool(struct swiotlb *swiotlb, phys_addr_t start,
+				size_t size)
 {
-	struct swiotlb *swiotlb = &default_swiotlb;
-	unsigned long i, bytes;
+	unsigned long i;
+	void *vaddr = phys_to_virt(start);
 
-	bytes = nslabs << IO_TLB_SHIFT;
+	size = ALIGN(size, 1 << IO_TLB_SHIFT);
+	swiotlb->nslabs = size >> IO_TLB_SHIFT;
+	swiotlb->nslabs = ALIGN(swiotlb->nslabs, IO_TLB_SEGSIZE);
 
-	swiotlb->nslabs = nslabs;
-	swiotlb->start = virt_to_phys(tlb);
-	swiotlb->end = swiotlb->start + bytes;
+	swiotlb->start = start;
+	swiotlb->end = swiotlb->start + size;
 
-	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
-	memset(tlb, 0, bytes);
+	set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT);
+	memset(vaddr, 0, size);
 
 	/*
 	 * Allocate and initialize the free list array.  This array is used
@@ -390,13 +391,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 		swiotlb->orig_addr[i] = INVALID_PHYS_ADDR;
 	}
 	swiotlb->index = 0;
-	no_iotlb_memory = false;
-
-	swiotlb_print_info();
 
-	late_alloc = 1;
-
-	swiotlb_set_max_segment(swiotlb->nslabs << IO_TLB_SHIFT);
 	spin_lock_init(&swiotlb->lock);
 
 	return 0;
@@ -410,6 +405,27 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	return -ENOMEM;
 }
 
+int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
+{
+	struct swiotlb *swiotlb = &default_swiotlb;
+	unsigned long bytes = nslabs << IO_TLB_SHIFT;
+	int ret;
+
+	ret = swiotlb_init_tlb_pool(swiotlb, virt_to_phys(tlb), bytes);
+	if (ret)
+		return ret;
+
+	no_iotlb_memory = false;
+
+	swiotlb_print_info();
+
+	late_alloc = 1;
+
+	swiotlb_set_max_segment(bytes);
+
+	return 0;
+}
+
 void __init swiotlb_exit(void)
 {
 	struct swiotlb *swiotlb = &default_swiotlb;
@@ -747,17 +763,20 @@ phys_addr_t get_swiotlb_start(void)
 }
 
 #ifdef CONFIG_DEBUG_FS
-
-static int __init swiotlb_create_debugfs(void)
+static void swiotlb_create_debugfs(struct swiotlb *swiotlb, const char *name,
+				   struct dentry *node)
 {
-	struct swiotlb *swiotlb = &default_swiotlb;
-
-	swiotlb->debugfs = debugfs_create_dir("swiotlb", NULL);
+	swiotlb->debugfs = debugfs_create_dir(name, node);
 	debugfs_create_ulong("io_tlb_nslabs", 0400, swiotlb->debugfs, &swiotlb->nslabs);
 	debugfs_create_ulong("io_tlb_used", 0400, swiotlb->debugfs, &swiotlb->used);
-	return 0;
 }
 
-late_initcall(swiotlb_create_debugfs);
+static int __init swiotlb_create_default_debugfs(void)
+{
+	swiotlb_create_debugfs(&default_swiotlb, "swiotlb", NULL);
+
+	return 0;
+}
 
+late_initcall(swiotlb_create_default_debugfs);
 #endif
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 05/14] swiotlb: Add DMA_RESTRICTED_POOL
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (3 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 04/14] swiotlb: Refactor swiotlb_late_init_with_tbl Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 06/14] swiotlb: Add restricted DMA pool Claire Chang
                   ` (9 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Add a new kconfig symbol, DMA_RESTRICTED_POOL, for restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 kernel/dma/Kconfig | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 479fc145acfc..97ff9f8dd3c8 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -83,6 +83,20 @@ config SWIOTLB
 	bool
 	select NEED_DMA_MAP_STATE
 
+config DMA_RESTRICTED_POOL
+	bool "DMA Restricted Pool"
+	depends on OF && OF_RESERVED_MEM
+	select SWIOTLB
+	help
+	  This enables support for restricted DMA pools which provide a level of
+	  DMA memory protection on systems with limited hardware protection
+	  capabilities, such as those lacking an IOMMU.
+
+	  For more information see
+	  <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
+	  and <kernel/dma/swiotlb.c>.
+	  If unsure, say "n".
+
 #
 # Should be selected if we can mmap non-coherent mappings to userspace.
 # The only thing that is really required is a way to set an uncached bit
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 06/14] swiotlb: Add restricted DMA pool
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (4 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 05/14] swiotlb: Add DMA_RESTRICTED_POOL Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 07/14] swiotlb: Update swiotlb API to gain a struct device argument Claire Chang
                   ` (8 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Add the initialization function to create restricted DMA pools from
matching reserved-memory nodes.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/device.h |  4 ++
 kernel/dma/swiotlb.c   | 94 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 7619a84f8ce4..08d440627b93 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -415,6 +415,7 @@ struct dev_links_info {
  * @dma_pools:	Dma pools (if dma'ble device).
  * @dma_mem:	Internal for coherent mem override.
  * @cma_area:	Contiguous memory area for dma allocations
+ * @dev_swiotlb: Internal for swiotlb override.
  * @archdata:	For arch-specific additions.
  * @of_node:	Associated device tree node.
  * @fwnode:	Associated device node supplied by platform firmware.
@@ -517,6 +518,9 @@ struct device {
 #ifdef CONFIG_DMA_CMA
 	struct cma *cma_area;		/* contiguous memory area for dma
 					   allocations */
+#endif
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	struct swiotlb *dev_swiotlb;
 #endif
 	/* arch specific additions */
 	struct dev_archdata	archdata;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index dc37951c6924..3a17451c5981 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -39,6 +39,13 @@
 #ifdef CONFIG_DEBUG_FS
 #include <linux/debugfs.h>
 #endif
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/slab.h>
+#endif
 
 #include <asm/io.h>
 #include <asm/dma.h>
@@ -75,7 +82,8 @@ enum swiotlb_force swiotlb_force;
  *              range check to see if the memory was in fact allocated by this
  *              API.
  * @nslabs:     The number of IO TLB blocks (in groups of 64) between @start and
- *              @end. This is command line adjustable via setup_io_tlb_npages.
+ *              @end. For default swiotlb, this is command line adjustable via
+ *              setup_io_tlb_npages.
  * @used:       The number of used IO TLB block.
  * @list:       The free list describing the number of free entries available
  *              from each index.
@@ -780,3 +788,87 @@ static int __init swiotlb_create_default_debugfs(void)
 
 late_initcall(swiotlb_create_default_debugfs);
 #endif
+
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
+				    struct device *dev)
+{
+	struct swiotlb *swiotlb = rmem->priv;
+	int ret;
+
+	if (dev->dev_swiotlb)
+		return -EBUSY;
+
+	/* Since multiple devices can share the same pool, the private data,
+	 * swiotlb struct, will be initialized by the first device attached
+	 * to it.
+	 */
+	if (!swiotlb) {
+		swiotlb = kzalloc(sizeof(*swiotlb), GFP_KERNEL);
+		if (!swiotlb)
+			return -ENOMEM;
+#ifdef CONFIG_ARM
+		unsigned long pfn = PHYS_PFN(reme->base);
+
+		if (!PageHighMem(pfn_to_page(pfn))) {
+			ret = -EINVAL;
+			goto cleanup;
+		}
+#endif /* CONFIG_ARM */
+
+		ret = swiotlb_init_tlb_pool(swiotlb, rmem->base, rmem->size);
+		if (ret)
+			goto cleanup;
+
+		rmem->priv = swiotlb;
+	}
+
+#ifdef CONFIG_DEBUG_FS
+	swiotlb_create_debugfs(swiotlb, rmem->name, default_swiotlb.debugfs);
+#endif /* CONFIG_DEBUG_FS */
+
+	dev->dev_swiotlb = swiotlb;
+
+	return 0;
+
+cleanup:
+	kfree(swiotlb);
+
+	return ret;
+}
+
+static void rmem_swiotlb_device_release(struct reserved_mem *rmem,
+					struct device *dev)
+{
+	if (!dev)
+		return;
+
+#ifdef CONFIG_DEBUG_FS
+	debugfs_remove_recursive(dev->dev_swiotlb->debugfs);
+#endif /* CONFIG_DEBUG_FS */
+	dev->dev_swiotlb = NULL;
+}
+
+static const struct reserved_mem_ops rmem_swiotlb_ops = {
+	.device_init = rmem_swiotlb_device_init,
+	.device_release = rmem_swiotlb_device_release,
+};
+
+static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
+{
+	unsigned long node = rmem->fdt_node;
+
+	if (of_get_flat_dt_prop(node, "reusable", NULL) ||
+	    of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
+	    of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
+	    of_get_flat_dt_prop(node, "no-map", NULL))
+		return -EINVAL;
+
+	rmem->ops = &rmem_swiotlb_ops;
+	pr_info("Reserved memory: created device swiotlb memory pool at %pa, size %ld MiB\n",
+		&rmem->base, (unsigned long)rmem->size / SZ_1M);
+	return 0;
+}
+
+RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 07/14] swiotlb: Update swiotlb API to gain a struct device argument
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (5 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 06/14] swiotlb: Add restricted DMA pool Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 08/14] swiotlb: Use restricted DMA pool if available Claire Chang
                   ` (7 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Introduce the get_swiotlb() getter and update all callers of
is_swiotlb_active(), is_swiotlb_buffer() and get_swiotlb_start() to gain
a struct device argument.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 drivers/iommu/dma-iommu.c | 12 ++++++------
 drivers/xen/swiotlb-xen.c |  4 ++--
 include/linux/swiotlb.h   | 10 +++++-----
 kernel/dma/direct.c       |  8 ++++----
 kernel/dma/direct.h       |  6 +++---
 kernel/dma/swiotlb.c      | 23 +++++++++++++++++------
 6 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index f659395e7959..abdbe14472cc 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -503,7 +503,7 @@ static void __iommu_dma_unmap_swiotlb(struct device *dev, dma_addr_t dma_addr,
 
 	__iommu_dma_unmap(dev, dma_addr, size);
 
-	if (unlikely(is_swiotlb_buffer(phys)))
+	if (unlikely(is_swiotlb_buffer(dev, phys)))
 		swiotlb_tbl_unmap_single(dev, phys, size,
 				iova_align(iovad, size), dir, attrs);
 }
@@ -580,7 +580,7 @@ static dma_addr_t __iommu_dma_map_swiotlb(struct device *dev, phys_addr_t phys,
 	}
 
 	iova = __iommu_dma_map(dev, phys, aligned_size, prot, dma_mask);
-	if ((iova == DMA_MAPPING_ERROR) && is_swiotlb_buffer(phys))
+	if ((iova == DMA_MAPPING_ERROR) && is_swiotlb_buffer(dev, phys))
 		swiotlb_tbl_unmap_single(dev, phys, org_size,
 				aligned_size, dir, attrs);
 
@@ -753,7 +753,7 @@ static void iommu_dma_sync_single_for_cpu(struct device *dev,
 	if (!dev_is_dma_coherent(dev))
 		arch_sync_dma_for_cpu(phys, size, dir);
 
-	if (is_swiotlb_buffer(phys))
+	if (is_swiotlb_buffer(dev, phys))
 		swiotlb_tbl_sync_single(dev, phys, size, dir, SYNC_FOR_CPU);
 }
 
@@ -766,7 +766,7 @@ static void iommu_dma_sync_single_for_device(struct device *dev,
 		return;
 
 	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
-	if (is_swiotlb_buffer(phys))
+	if (is_swiotlb_buffer(dev, phys))
 		swiotlb_tbl_sync_single(dev, phys, size, dir, SYNC_FOR_DEVICE);
 
 	if (!dev_is_dma_coherent(dev))
@@ -787,7 +787,7 @@ static void iommu_dma_sync_sg_for_cpu(struct device *dev,
 		if (!dev_is_dma_coherent(dev))
 			arch_sync_dma_for_cpu(sg_phys(sg), sg->length, dir);
 
-		if (is_swiotlb_buffer(sg_phys(sg)))
+		if (is_swiotlb_buffer(dev, sg_phys(sg)))
 			swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length,
 						dir, SYNC_FOR_CPU);
 	}
@@ -804,7 +804,7 @@ static void iommu_dma_sync_sg_for_device(struct device *dev,
 		return;
 
 	for_each_sg(sgl, sg, nelems, i) {
-		if (is_swiotlb_buffer(sg_phys(sg)))
+		if (is_swiotlb_buffer(dev, sg_phys(sg)))
 			swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length,
 						dir, SYNC_FOR_DEVICE);
 
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 91f8c68d1a9b..f424d46756b1 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 (is_swiotlb_active()) {
-		xen_io_tlb_start = phys_to_virt(get_swiotlb_start());
+	if (is_swiotlb_active(NULL)) {
+		xen_io_tlb_start = phys_to_virt(get_swiotlb_start(NULL));
 		goto end;
 	}
 
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 041611bf3c2a..f13a52a97382 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -71,16 +71,16 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
 
-bool is_swiotlb_buffer(phys_addr_t paddr);
+bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr);
 void __init swiotlb_exit(void);
 unsigned int swiotlb_max_segment(void);
 size_t swiotlb_max_mapping_size(struct device *dev);
-bool is_swiotlb_active(void);
-phys_addr_t get_swiotlb_start(void);
+bool is_swiotlb_active(struct device *dev);
+phys_addr_t get_swiotlb_start(struct device *dev);
 void __init swiotlb_adjust_size(unsigned long new_size);
 #else
 #define swiotlb_force SWIOTLB_NO_FORCE
-static inline bool is_swiotlb_buffer(phys_addr_t paddr)
+static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
 	return false;
 }
@@ -96,7 +96,7 @@ static inline size_t swiotlb_max_mapping_size(struct device *dev)
 	return SIZE_MAX;
 }
 
-static inline bool is_swiotlb_active(void)
+static inline bool is_swiotlb_active(struct device *dev)
 {
 	return false;
 }
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 002268262c9a..30ccbc08e229 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -343,7 +343,7 @@ void dma_direct_sync_sg_for_device(struct device *dev,
 	for_each_sg(sgl, sg, nents, i) {
 		phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
 
-		if (unlikely(is_swiotlb_buffer(paddr)))
+		if (unlikely(is_swiotlb_buffer(dev, paddr)))
 			swiotlb_tbl_sync_single(dev, paddr, sg->length,
 					dir, SYNC_FOR_DEVICE);
 
@@ -369,7 +369,7 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
 		if (!dev_is_dma_coherent(dev))
 			arch_sync_dma_for_cpu(paddr, sg->length, dir);
 
-		if (unlikely(is_swiotlb_buffer(paddr)))
+		if (unlikely(is_swiotlb_buffer(dev, paddr)))
 			swiotlb_tbl_sync_single(dev, paddr, sg->length, dir,
 					SYNC_FOR_CPU);
 
@@ -495,7 +495,7 @@ int dma_direct_supported(struct device *dev, u64 mask)
 size_t dma_direct_max_mapping_size(struct device *dev)
 {
 	/* If SWIOTLB is active, use its maximum mapping size */
-	if (is_swiotlb_active() &&
+	if (is_swiotlb_active(dev) &&
 	    (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE))
 		return swiotlb_max_mapping_size(dev);
 	return SIZE_MAX;
@@ -504,7 +504,7 @@ size_t dma_direct_max_mapping_size(struct device *dev)
 bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr)
 {
 	return !dev_is_dma_coherent(dev) ||
-		is_swiotlb_buffer(dma_to_phys(dev, dma_addr));
+		is_swiotlb_buffer(dev, dma_to_phys(dev, dma_addr));
 }
 
 /**
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index b98615578737..7b83b1595989 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h
@@ -56,7 +56,7 @@ static inline void dma_direct_sync_single_for_device(struct device *dev,
 {
 	phys_addr_t paddr = dma_to_phys(dev, addr);
 
-	if (unlikely(is_swiotlb_buffer(paddr)))
+	if (unlikely(is_swiotlb_buffer(dev, paddr)))
 		swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);
 
 	if (!dev_is_dma_coherent(dev))
@@ -73,7 +73,7 @@ static inline void dma_direct_sync_single_for_cpu(struct device *dev,
 		arch_sync_dma_for_cpu_all();
 	}
 
-	if (unlikely(is_swiotlb_buffer(paddr)))
+	if (unlikely(is_swiotlb_buffer(dev, paddr)))
 		swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
 
 	if (dir == DMA_FROM_DEVICE)
@@ -113,7 +113,7 @@ static inline void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		dma_direct_sync_single_for_cpu(dev, addr, size, dir);
 
-	if (unlikely(is_swiotlb_buffer(phys)))
+	if (unlikely(is_swiotlb_buffer(dev, phys)))
 		swiotlb_tbl_unmap_single(dev, phys, size, size, dir, attrs);
 }
 #endif /* _KERNEL_DMA_DIRECT_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 3a17451c5981..e22e7ae75f1c 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -107,6 +107,11 @@ struct swiotlb {
 };
 static struct swiotlb default_swiotlb;
 
+static inline struct swiotlb *get_swiotlb(struct device *dev)
+{
+	return &default_swiotlb;
+}
+
 /*
  * Max segment that we can provide which (if pages are contingous) will
  * not be bounced (unless SWIOTLB_FORCE is set).
@@ -751,23 +756,29 @@ size_t swiotlb_max_mapping_size(struct device *dev)
 	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
 }
 
-bool is_swiotlb_active(void)
+bool is_swiotlb_active(struct device *dev)
 {
+	struct swiotlb *swiotlb = get_swiotlb(dev);
+
 	/*
 	 * When SWIOTLB is initialized, even if swiotlb->start points to
 	 * physical address zero, swiotlb->end surely doesn't.
 	 */
-	return default_swiotlb.end != 0;
+	return swiotlb->end != 0;
 }
 
-bool is_swiotlb_buffer(phys_addr_t paddr)
+bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
-	return paddr >= default_swiotlb.start && paddr < default_swiotlb.end;
+	struct swiotlb *swiotlb = get_swiotlb(dev);
+
+	return paddr >= swiotlb->start && paddr < swiotlb->end;
 }
 
-phys_addr_t get_swiotlb_start(void)
+phys_addr_t get_swiotlb_start(struct device *dev)
 {
-	return default_swiotlb.start;
+	struct swiotlb *swiotlb = get_swiotlb(dev);
+
+	return swiotlb->start;
 }
 
 #ifdef CONFIG_DEBUG_FS
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 08/14] swiotlb: Use restricted DMA pool if available
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (6 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 07/14] swiotlb: Update swiotlb API to gain a struct device argument Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 09/14] swiotlb: Refactor swiotlb_tbl_{map,unmap}_single Claire Chang
                   ` (6 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

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.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h | 13 +++++++++++++
 kernel/dma/direct.h     |  2 +-
 kernel/dma/swiotlb.c    | 20 +++++++++++++++++---
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index f13a52a97382..76f86c684524 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -71,6 +71,15 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
 
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+bool is_swiotlb_force(struct device *dev);
+#else
+static inline bool is_swiotlb_force(struct device *dev)
+{
+	return unlikely(swiotlb_force == SWIOTLB_FORCE);
+}
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
+
 bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr);
 void __init swiotlb_exit(void);
 unsigned int swiotlb_max_segment(void);
@@ -80,6 +89,10 @@ phys_addr_t get_swiotlb_start(struct device *dev);
 void __init swiotlb_adjust_size(unsigned long new_size);
 #else
 #define swiotlb_force SWIOTLB_NO_FORCE
+static inline bool is_swiotlb_force(struct device *dev)
+{
+	return false;
+}
 static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
 	return false;
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index 7b83b1595989..b011db1b625d 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h
@@ -87,7 +87,7 @@ 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 (is_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 e22e7ae75f1c..6fdebde8fb1f 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -40,6 +40,7 @@
 #include <linux/debugfs.h>
 #endif
 #ifdef CONFIG_DMA_RESTRICTED_POOL
+#include <linux/device.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
@@ -109,6 +110,10 @@ static struct swiotlb default_swiotlb;
 
 static inline struct swiotlb *get_swiotlb(struct device *dev)
 {
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (dev && dev->dev_swiotlb)
+		return dev->dev_swiotlb;
+#endif
 	return &default_swiotlb;
 }
 
@@ -508,7 +513,7 @@ 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)
 {
-	struct swiotlb *swiotlb = &default_swiotlb;
+	struct swiotlb *swiotlb = get_swiotlb(hwdev);
 	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, swiotlb->start);
 	unsigned long flags;
 	phys_addr_t tlb_addr;
@@ -519,7 +524,11 @@ 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;
 
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (no_iotlb_memory && !hwdev->dev_swiotlb)
+#else
 	if (no_iotlb_memory)
+#endif
 		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
 
 	if (mem_encrypt_active())
@@ -641,7 +650,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 			      size_t mapping_size, size_t alloc_size,
 			      enum dma_data_direction dir, unsigned long attrs)
 {
-	struct swiotlb *swiotlb = &default_swiotlb;
+	struct swiotlb *swiotlb = get_swiotlb(hwdev);
 	unsigned long flags;
 	int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 	int index = (tlb_addr - swiotlb->start) >> IO_TLB_SHIFT;
@@ -689,7 +698,7 @@ 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)
 {
-	struct swiotlb *swiotlb = &default_swiotlb;
+	struct swiotlb *swiotlb = get_swiotlb(hwdev);
 	int index = (tlb_addr - swiotlb->start) >> IO_TLB_SHIFT;
 	phys_addr_t orig_addr = swiotlb->orig_addr[index];
 
@@ -801,6 +810,11 @@ late_initcall(swiotlb_create_default_debugfs);
 #endif
 
 #ifdef CONFIG_DMA_RESTRICTED_POOL
+bool is_swiotlb_force(struct device *dev)
+{
+	return unlikely(swiotlb_force == SWIOTLB_FORCE) || dev->dev_swiotlb;
+}
+
 static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
 				    struct device *dev)
 {
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 09/14] swiotlb: Refactor swiotlb_tbl_{map,unmap}_single
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (7 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 08/14] swiotlb: Use restricted DMA pool if available Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 10/14] dma-direct: Add a new wrapper __dma_direct_free_pages() Claire Chang
                   ` (5 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Refactor swiotlb_tbl_{map,unmap}_single to make the code reusable for
dev_swiotlb_{alloc,free}.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 kernel/dma/swiotlb.c | 116 ++++++++++++++++++++++++++-----------------
 1 file changed, 71 insertions(+), 45 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 6fdebde8fb1f..f64cbe6e84cc 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -509,14 +509,12 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
 	}
 }
 
-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)
+static int swiotlb_tbl_find_free_region(struct device *hwdev,
+					dma_addr_t tbl_dma_addr,
+					size_t alloc_size, unsigned long attrs)
 {
 	struct swiotlb *swiotlb = get_swiotlb(hwdev);
-	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, swiotlb->start);
 	unsigned long flags;
-	phys_addr_t tlb_addr;
 	unsigned int nslots, stride, index, wrap;
 	int i;
 	unsigned long mask;
@@ -531,15 +529,6 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 #endif
 		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
 
-	if (mem_encrypt_active())
-		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
-
-	if (mapping_size > alloc_size) {
-		dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
-			      mapping_size, alloc_size);
-		return (phys_addr_t)DMA_MAPPING_ERROR;
-	}
-
 	mask = dma_get_seg_boundary(hwdev);
 
 	tbl_dma_addr &= mask;
@@ -601,7 +590,6 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 				swiotlb->list[i] = 0;
 			for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && swiotlb->list[i]; i--)
 				swiotlb->list[i] = ++count;
-			tlb_addr = swiotlb->start + (index << IO_TLB_SHIFT);
 
 			/*
 			 * Update the indices to avoid searching in the next
@@ -624,45 +612,20 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 	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, swiotlb->nslabs, tmp_io_tlb_used);
-	return (phys_addr_t)DMA_MAPPING_ERROR;
+	return -ENOMEM;
+
 found:
 	swiotlb->used += nslots;
 	spin_unlock_irqrestore(&swiotlb->lock, flags);
 
-	/*
-	 * Save away the mapping from the original address to the DMA address.
-	 * This is needed when we sync the memory.  Then we sync the buffer if
-	 * needed.
-	 */
-	for (i = 0; i < nslots; i++)
-		swiotlb->orig_addr[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);
-
-	return tlb_addr;
+	return index;
 }
 
-/*
- * tlb_addr is the physical address of the bounce buffer to unmap.
- */
-void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
-			      size_t mapping_size, size_t alloc_size,
-			      enum dma_data_direction dir, unsigned long attrs)
+static void swiotlb_tbl_release_region(struct device *hwdev, int index, size_t size)
 {
 	struct swiotlb *swiotlb = get_swiotlb(hwdev);
 	unsigned long flags;
-	int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
-	int index = (tlb_addr - swiotlb->start) >> IO_TLB_SHIFT;
-	phys_addr_t orig_addr = swiotlb->orig_addr[index];
-
-	/*
-	 * First, sync the memory before unmapping the entry
-	 */
-	if (orig_addr != INVALID_PHYS_ADDR &&
-	    !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
-		swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
+	int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 
 	/*
 	 * Return the buffer to the free list by setting the corresponding
@@ -694,6 +657,69 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 	spin_unlock_irqrestore(&swiotlb->lock, flags);
 }
 
+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)
+{
+	struct swiotlb *swiotlb = get_swiotlb(hwdev);
+	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, swiotlb->start);
+	phys_addr_t tlb_addr;
+	unsigned int nslots, index;
+	int i;
+
+	if (mem_encrypt_active())
+		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
+
+	if (mapping_size > alloc_size) {
+		dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
+			      mapping_size, alloc_size);
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
+
+	index = swiotlb_tbl_find_free_region(hwdev, tbl_dma_addr, alloc_size, attrs);
+	if (index < 0)
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+
+	tlb_addr = swiotlb->start + (index << IO_TLB_SHIFT);
+
+	/*
+	 * Save away the mapping from the original address to the DMA address.
+	 * This is needed when we sync the memory.  Then we sync the buffer if
+	 * needed.
+	 */
+	nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	for (i = 0; i < nslots; i++)
+		swiotlb->orig_addr[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);
+
+	return tlb_addr;
+}
+
+/*
+ * tlb_addr is the physical address of the bounce buffer to unmap.
+ */
+void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
+			      size_t mapping_size, size_t alloc_size,
+			      enum dma_data_direction dir, unsigned long attrs)
+{
+	struct swiotlb *swiotlb = get_swiotlb(hwdev);
+	int index = (tlb_addr - swiotlb->start) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = swiotlb->orig_addr[index];
+
+	/*
+	 * First, sync the memory before unmapping the entry
+	 */
+	if (orig_addr != INVALID_PHYS_ADDR &&
+	    !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+	    ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+		swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
+
+	swiotlb_tbl_release_region(hwdev, index, alloc_size);
+}
+
 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)
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 10/14] dma-direct: Add a new wrapper __dma_direct_free_pages()
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (8 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 09/14] swiotlb: Refactor swiotlb_tbl_{map,unmap}_single Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 11/14] swiotlb: Add is_dev_swiotlb_force() Claire Chang
                   ` (4 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Add a new wrapper __dma_direct_free_pages() that will be useful later
for dev_swiotlb_free().

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 kernel/dma/direct.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 30ccbc08e229..a76a1a2f24da 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -75,6 +75,11 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 		min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
 }
 
+static void __dma_direct_free_pages(struct device *dev, struct page *page, size_t size)
+{
+	dma_free_contiguous(dev, page, size);
+}
+
 static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 		gfp_t gfp)
 {
@@ -237,7 +242,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 			return NULL;
 	}
 out_free_pages:
-	dma_free_contiguous(dev, page, size);
+	__dma_direct_free_pages(dev, page, size);
 	return NULL;
 }
 
@@ -273,7 +278,7 @@ void dma_direct_free(struct device *dev, size_t size,
 	else if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED))
 		arch_dma_clear_uncached(cpu_addr, size);
 
-	dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size);
+	__dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size);
 }
 
 struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
@@ -310,7 +315,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 	return page;
 out_free_pages:
-	dma_free_contiguous(dev, page, size);
+	__dma_direct_free_pages(dev, page, size);
 	return NULL;
 }
 
@@ -329,7 +334,7 @@ void dma_direct_free_pages(struct device *dev, size_t size,
 	if (force_dma_unencrypted(dev))
 		set_memory_encrypted((unsigned long)vaddr, 1 << page_order);
 
-	dma_free_contiguous(dev, page, size);
+	__dma_direct_free_pages(dev, page, size);
 }
 
 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 11/14] swiotlb: Add is_dev_swiotlb_force()
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (9 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 10/14] dma-direct: Add a new wrapper __dma_direct_free_pages() Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support Claire Chang
                   ` (3 subsequent siblings)
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Add is_dev_swiotlb_force() which returns true if the device has
restricted DMA pool (e.g. dev->dev_swiotlb is set).

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h | 9 +++++++++
 kernel/dma/swiotlb.c    | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 76f86c684524..b9f2a250c8da 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -73,11 +73,16 @@ extern enum swiotlb_force swiotlb_force;
 
 #ifdef CONFIG_DMA_RESTRICTED_POOL
 bool is_swiotlb_force(struct device *dev);
+bool is_dev_swiotlb_force(struct device *dev);
 #else
 static inline bool is_swiotlb_force(struct device *dev)
 {
 	return unlikely(swiotlb_force == SWIOTLB_FORCE);
 }
+static inline bool is_dev_swiotlb_force(struct device *dev)
+{
+	return false;
+}
 #endif /* CONFIG_DMA_RESTRICTED_POOL */
 
 bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr);
@@ -93,6 +98,10 @@ static inline bool is_swiotlb_force(struct device *dev)
 {
 	return false;
 }
+static inline bool is_dev_swiotlb_force(struct device *dev)
+{
+	return false;
+}
 static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
 	return false;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index f64cbe6e84cc..fd9c1bd183ac 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -841,6 +841,11 @@ bool is_swiotlb_force(struct device *dev)
 	return unlikely(swiotlb_force == SWIOTLB_FORCE) || dev->dev_swiotlb;
 }
 
+bool is_dev_swiotlb_force(struct device *dev)
+{
+	return dev->dev_swiotlb;
+}
+
 static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
 				    struct device *dev)
 {
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support.
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (10 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 11/14] swiotlb: Add is_dev_swiotlb_force() Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-02-26  4:17   ` Claire Chang
  2021-02-09  6:21 ` [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool Claire Chang
                   ` (2 subsequent siblings)
  14 siblings, 1 reply; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Add the functions, dev_swiotlb_{alloc,free} to support the memory
allocation from restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h |  2 ++
 kernel/dma/direct.c     | 30 ++++++++++++++++++++++--------
 kernel/dma/swiotlb.c    | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 8 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index b9f2a250c8da..2cd39e102915 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -74,6 +74,8 @@ extern enum swiotlb_force swiotlb_force;
 #ifdef CONFIG_DMA_RESTRICTED_POOL
 bool is_swiotlb_force(struct device *dev);
 bool is_dev_swiotlb_force(struct device *dev);
+struct page *dev_swiotlb_alloc(struct device *dev, size_t size, gfp_t gfp);
+bool dev_swiotlb_free(struct device *dev, struct page *page, size_t size);
 #else
 static inline bool is_swiotlb_force(struct device *dev)
 {
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index a76a1a2f24da..f9a9321f7559 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -12,6 +12,7 @@
 #include <linux/pfn.h>
 #include <linux/vmalloc.h>
 #include <linux/set_memory.h>
+#include <linux/swiotlb.h>
 #include <linux/slab.h>
 #include "direct.h"
 
@@ -77,6 +78,10 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 
 static void __dma_direct_free_pages(struct device *dev, struct page *page, size_t size)
 {
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (dev_swiotlb_free(dev, page, size))
+		return;
+#endif
 	dma_free_contiguous(dev, page, size);
 }
 
@@ -89,6 +94,12 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 
 	WARN_ON_ONCE(!PAGE_ALIGNED(size));
 
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	page = dev_swiotlb_alloc(dev, size, gfp);
+	if (page)
+		return page;
+#endif
+
 	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
 					   &phys_limit);
 	page = dma_alloc_contiguous(dev, size, gfp);
@@ -147,7 +158,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 		gfp |= __GFP_NOWARN;
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev)) {
+	    !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) {
 		page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
 		if (!page)
 			return NULL;
@@ -160,8 +171,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	}
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-	    !dev_is_dma_coherent(dev))
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) &&
+	    !is_dev_swiotlb_force(dev))
 		return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
 
 	/*
@@ -171,7 +182,9 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 	    !gfpflags_allow_blocking(gfp) &&
 	    (force_dma_unencrypted(dev) ||
-	     (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev))))
+	     (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+	      !dev_is_dma_coherent(dev))) &&
+	    !is_dev_swiotlb_force(dev))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	/* we always manually zero the memory once we are done */
@@ -252,15 +265,15 @@ void dma_direct_free(struct device *dev, size_t size,
 	unsigned int page_order = get_order(size);
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev)) {
+	    !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) {
 		/* cpu_addr is a struct page cookie, not a kernel address */
 		dma_free_contiguous(dev, cpu_addr, size);
 		return;
 	}
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-	    !dev_is_dma_coherent(dev)) {
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) &&
+	    !is_dev_swiotlb_force(dev)) {
 		arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
 		return;
 	}
@@ -288,7 +301,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	void *ret;
 
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
-	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp))
+	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) &&
+	    !is_dev_swiotlb_force(dev))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	page = __dma_direct_alloc_pages(dev, size, gfp);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index fd9c1bd183ac..8b77fd64199e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -836,6 +836,40 @@ late_initcall(swiotlb_create_default_debugfs);
 #endif
 
 #ifdef CONFIG_DMA_RESTRICTED_POOL
+struct page *dev_swiotlb_alloc(struct device *dev, size_t size, gfp_t gfp)
+{
+	struct swiotlb *swiotlb;
+	phys_addr_t tlb_addr;
+	unsigned int index;
+
+	/* dev_swiotlb_alloc can be used only in the context which permits sleeping. */
+	if (!dev->dev_swiotlb || !gfpflags_allow_blocking(gfp))
+		return NULL;
+
+	swiotlb = dev->dev_swiotlb;
+	index = swiotlb_tbl_find_free_region(dev, swiotlb->start, size, 0);
+	if (index < 0)
+		return NULL;
+
+	tlb_addr = swiotlb->start + (index << IO_TLB_SHIFT);
+
+	return pfn_to_page(PFN_DOWN(tlb_addr));
+}
+
+bool dev_swiotlb_free(struct device *dev, struct page *page, size_t size)
+{
+	unsigned int index;
+	phys_addr_t tlb_addr = page_to_phys(page);
+
+	if (!is_swiotlb_buffer(dev, tlb_addr))
+		return false;
+
+	index = (tlb_addr - dev->dev_swiotlb->start) >> IO_TLB_SHIFT;
+	swiotlb_tbl_release_region(dev, index, size);
+
+	return true;
+}
+
 bool is_swiotlb_force(struct device *dev)
 {
 	return unlikely(swiotlb_force == SWIOTLB_FORCE) || dev->dev_swiotlb;
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (11 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-03-10 16:07   ` Will Deacon
  2021-02-09  6:21 ` [PATCH v4 14/14] of: Add plumbing for " Claire Chang
  2021-04-22  8:20 ` [PATCH v4 00/14] Restricted DMA Claire Chang
  14 siblings, 1 reply; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

Introduce the new compatible string, restricted-dma-pool, for restricted
DMA. One can specify the address and length of the restricted DMA memory
region by restricted-dma-pool in the reserved-memory node.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 .../reserved-memory/reserved-memory.txt       | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
index e8d3096d922c..fc9a12c2f679 100644
--- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
@@ -51,6 +51,20 @@ compatible (optional) - standard definition
           used as a shared pool of DMA buffers for a set of devices. It can
           be used by an operating system to instantiate the necessary pool
           management subsystem if necessary.
+        - restricted-dma-pool: This indicates a region of memory meant to be
+          used as a pool of restricted DMA buffers for a set of devices. The
+          memory region would be the only region accessible to those devices.
+          When using this, the no-map and reusable properties must not be set,
+          so the operating system can create a virtual mapping that will be used
+          for synchronization. The main purpose for restricted DMA is to
+          mitigate the lack of DMA access control on systems without an IOMMU,
+          which could result in the DMA accessing the system memory at
+          unexpected times and/or unexpected addresses, possibly leading to data
+          leakage or corruption. The feature on its own provides 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 way to lock down
+          the memory access, e.g., MPU.
         - vendor specific string in the form <vendor>,[<device>-]<usage>
 no-map (optional) - empty property
     - Indicates the operating system must not create a virtual mapping
@@ -120,6 +134,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
 			compatible = "acme,multimedia-memory";
 			reg = <0x77000000 0x4000000>;
 		};
+
+		restricted_dma_mem_reserved: restricted_dma_mem_reserved {
+			compatible = "restricted-dma-pool";
+			reg = <0x50000000 0x400000>;
+		};
 	};
 
 	/* ... */
@@ -138,4 +157,9 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
 		memory-region = <&multimedia_reserved>;
 		/* ... */
 	};
+
+	pcie_device: pcie_device@0,0 {
+		memory-region = <&restricted_dma_mem_reserved>;
+		/* ... */
+	};
 };
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v4 14/14] of: Add plumbing for restricted DMA pool
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (12 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool Claire Chang
@ 2021-02-09  6:21 ` Claire Chang
  2021-04-22  8:20 ` [PATCH v4 00/14] Restricted DMA Claire Chang
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-09  6:21 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan, Claire Chang

If a device is not behind an IOMMU, we look up the device node and set
up the restricted DMA when the restricted-dma-pool is presented.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 drivers/of/address.c    | 25 +++++++++++++++++++++++++
 drivers/of/device.c     |  3 +++
 drivers/of/of_private.h |  5 +++++
 3 files changed, 33 insertions(+)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 73ddf2540f3f..b6093c9b135d 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -8,6 +8,7 @@
 #include <linux/logic_pio.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/pci.h>
 #include <linux/pci_regs.h>
 #include <linux/sizes.h>
@@ -1094,3 +1095,27 @@ bool of_dma_is_coherent(struct device_node *np)
 	return false;
 }
 EXPORT_SYMBOL_GPL(of_dma_is_coherent);
+
+int of_dma_set_restricted_buffer(struct device *dev)
+{
+	struct device_node *node;
+	int count, i;
+
+	if (!dev->of_node)
+		return 0;
+
+	count = of_property_count_elems_of_size(dev->of_node, "memory-region",
+						sizeof(phandle));
+	for (i = 0; i < count; i++) {
+		node = of_parse_phandle(dev->of_node, "memory-region", i);
+		/* There might be multiple memory regions, but only one
+		 * restriced-dma-pool region is allowed.
+		 */
+		if (of_device_is_compatible(node, "restricted-dma-pool") &&
+		    of_device_is_available(node))
+			return of_reserved_mem_device_init_by_idx(
+				dev, dev->of_node, i);
+	}
+
+	return 0;
+}
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 1122daa8e273..38c631f1fafa 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -186,6 +186,9 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
 
 	arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
 
+	if (!iommu)
+		return of_dma_set_restricted_buffer(dev);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_dma_configure_id);
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index d9e6a324de0a..28a2dfa197ba 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -161,12 +161,17 @@ struct bus_dma_region;
 #if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
 int of_dma_get_range(struct device_node *np,
 		const struct bus_dma_region **map);
+int of_dma_set_restricted_buffer(struct device *dev);
 #else
 static inline int of_dma_get_range(struct device_node *np,
 		const struct bus_dma_region **map)
 {
 	return -ENODEV;
 }
+static inline int of_dma_get_restricted_buffer(struct device *dev)
+{
+	return -ENODEV;
+}
 #endif
 
 #endif /* _LINUX_OF_PRIVATE_H */
-- 
2.30.0.478.g8a0d178c01-goog



^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start
  2021-02-09  6:21 ` [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start Claire Chang
@ 2021-02-09  8:40   ` Christoph Hellwig
  0 siblings, 0 replies; 23+ messages in thread
From: Christoph Hellwig @ 2021-02-09  8:40 UTC (permalink / raw)
  To: Claire Chang
  Cc: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski, benh, paulus,
	list@263.net:IOMMU DRIVERS, sstabellini, Robin Murphy,
	grant.likely, xypron.glpk, Thierry Reding, mingo, bauerman,
	peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan

On Tue, Feb 09, 2021 at 02:21:18PM +0800, Claire Chang wrote:
> This can be dropped if Christoph's swiotlb cleanups are landed.
> https://lore.kernel.org/linux-iommu/20210207160934.2955931-1-hch@lst.de/T/#m7124f29b6076d462101fcff6433295157621da09 

FYI, I've also started looking into additional cleanups based on your
struct in this branch, but I'd like to wait for all the previous
changes to settle first:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/swiotlb-struct


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support.
  2021-02-09  6:21 ` [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support Claire Chang
@ 2021-02-26  4:17   ` Claire Chang
  2021-02-26  5:17     ` Christoph Hellwig
  0 siblings, 1 reply; 23+ messages in thread
From: Claire Chang @ 2021-02-26  4:17 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan

> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index fd9c1bd183ac..8b77fd64199e 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -836,6 +836,40 @@ late_initcall(swiotlb_create_default_debugfs);
>  #endif
>
>  #ifdef CONFIG_DMA_RESTRICTED_POOL
> +struct page *dev_swiotlb_alloc(struct device *dev, size_t size, gfp_t gfp)
> +{
> +       struct swiotlb *swiotlb;
> +       phys_addr_t tlb_addr;
> +       unsigned int index;
> +
> +       /* dev_swiotlb_alloc can be used only in the context which permits sleeping. */
> +       if (!dev->dev_swiotlb || !gfpflags_allow_blocking(gfp))

Just noticed that !gfpflags_allow_blocking(gfp) shouldn't be here.

Hi Christoph,

Do you think I should fix this and rebase on the latest linux-next
now? I wonder if there are more factor and clean up coming and I
should wait after that.

Thanks,
Claire


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support.
  2021-02-26  4:17   ` Claire Chang
@ 2021-02-26  5:17     ` Christoph Hellwig
  2021-02-26  9:35       ` Claire Chang
  0 siblings, 1 reply; 23+ messages in thread
From: Christoph Hellwig @ 2021-02-26  5:17 UTC (permalink / raw)
  To: Claire Chang
  Cc: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski, benh, paulus,
	list@263.net:IOMMU DRIVERS, sstabellini, Robin Murphy,
	grant.likely, xypron.glpk, Thierry Reding, mingo, bauerman,
	peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan

On Fri, Feb 26, 2021 at 12:17:50PM +0800, Claire Chang wrote:
> Do you think I should fix this and rebase on the latest linux-next
> now? I wonder if there are more factor and clean up coming and I
> should wait after that.

Here is my preferred plan:

 1) wait for my series to support the min alignment in swiotlb to
    land in Linus tree
 2) I'll resend my series with the further swiotlb cleanup and
    refactoring, which includes a slightly rebased version of your
    patch to add the io_tlb_mem structure
 3) resend your series on top of that as a baseline

This is my current WIP tree for 2:

  http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/swiotlb-struct


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support.
  2021-02-26  5:17     ` Christoph Hellwig
@ 2021-02-26  9:35       ` Claire Chang
  0 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-02-26  9:35 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross, Marek Szyprowski,
	benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan

On Fri, Feb 26, 2021 at 1:17 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Fri, Feb 26, 2021 at 12:17:50PM +0800, Claire Chang wrote:
> > Do you think I should fix this and rebase on the latest linux-next
> > now? I wonder if there are more factor and clean up coming and I
> > should wait after that.
>
> Here is my preferred plan:
>
>  1) wait for my series to support the min alignment in swiotlb to
>     land in Linus tree
>  2) I'll resend my series with the further swiotlb cleanup and
>     refactoring, which includes a slightly rebased version of your
>     patch to add the io_tlb_mem structure
>  3) resend your series on top of that as a baseline
>
> This is my current WIP tree for 2:
>
>   http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/swiotlb-struct

Sounds good to me. Thanks!


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool
  2021-02-09  6:21 ` [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool Claire Chang
@ 2021-03-10 16:07   ` Will Deacon
  2021-03-10 21:40     ` Rob Herring
  0 siblings, 1 reply; 23+ messages in thread
From: Will Deacon @ 2021-03-10 16:07 UTC (permalink / raw)
  To: Claire Chang
  Cc: Rob Herring, mpe, Joerg Roedel, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski, benh, paulus,
	list@263.net:IOMMU DRIVERS, sstabellini, Robin Murphy,
	grant.likely, xypron.glpk, Thierry Reding, mingo, bauerman,
	peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan

Hi Claire,

On Tue, Feb 09, 2021 at 02:21:30PM +0800, Claire Chang wrote:
> Introduce the new compatible string, restricted-dma-pool, for restricted
> DMA. One can specify the address and length of the restricted DMA memory
> region by restricted-dma-pool in the reserved-memory node.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  .../reserved-memory/reserved-memory.txt       | 24 +++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> index e8d3096d922c..fc9a12c2f679 100644
> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> @@ -51,6 +51,20 @@ compatible (optional) - standard definition
>            used as a shared pool of DMA buffers for a set of devices. It can
>            be used by an operating system to instantiate the necessary pool
>            management subsystem if necessary.
> +        - restricted-dma-pool: This indicates a region of memory meant to be
> +          used as a pool of restricted DMA buffers for a set of devices. The
> +          memory region would be the only region accessible to those devices.
> +          When using this, the no-map and reusable properties must not be set,
> +          so the operating system can create a virtual mapping that will be used
> +          for synchronization. The main purpose for restricted DMA is to
> +          mitigate the lack of DMA access control on systems without an IOMMU,
> +          which could result in the DMA accessing the system memory at
> +          unexpected times and/or unexpected addresses, possibly leading to data
> +          leakage or corruption. The feature on its own provides 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 way to lock down
> +          the memory access, e.g., MPU.

As far as I can tell, these pools work with both static allocations (which
seem to match your use-case where firmware has preconfigured the DMA ranges)
but also with dynamic allocations where a 'size' property is present instead
of the 'reg' property and the kernel is responsible for allocating the
reservation during boot. Am I right and, if so, is that deliberate?

I ask because I think that would potentially be useful to us for the
Protected KVM work, where we need to bounce virtio memory accesses via
guest-determined windows because the guest memory is generally inaccessible
to the host. We've been hacking this using a combination of "swiotlb=force"
and set_memory_{decrypted,encrypted}() but it would be much better to
leverage the stuff you have here.

Also:

> +
> +		restricted_dma_mem_reserved: restricted_dma_mem_reserved {
> +			compatible = "restricted-dma-pool";
> +			reg = <0x50000000 0x400000>;
> +		};
>  	};
>  
>  	/* ... */
> @@ -138,4 +157,9 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  		memory-region = <&multimedia_reserved>;
>  		/* ... */
>  	};
> +
> +	pcie_device: pcie_device@0,0 {
> +		memory-region = <&restricted_dma_mem_reserved>;
> +		/* ... */
> +	};

I find this example a bit weird, as I didn't think we usually had DT nodes
for PCI devices; rather they are discovered as a result of probing config
space. Is the idea that you have one reserved memory region attached to the
RC and all the PCI devices below that share the region, or is there a need
for a mapping mechanism?

Will


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool
  2021-03-10 16:07   ` Will Deacon
@ 2021-03-10 21:40     ` Rob Herring
  2021-03-11  5:04       ` Florian Fainelli
  0 siblings, 1 reply; 23+ messages in thread
From: Rob Herring @ 2021-03-10 21:40 UTC (permalink / raw)
  To: Will Deacon
  Cc: Claire Chang, Michael Ellerman, Joerg Roedel, Frank Rowand,
	Konrad Rzeszutek Wilk, Boris Ostrovsky, Juergen Gross,
	Christoph Hellwig, Marek Szyprowski, Benjamin Herrenschmidt,
	Paul Mackerras, list@263.net:IOMMU DRIVERS, Stefano Stabellini,
	Robin Murphy, Grant Likely, Heinrich Schuchardt, Thierry Reding,
	Ingo Molnar, Thiago Jung Bauermann, Peter Zijlstra, Greg KH,
	Saravana Kannan, Rafael J . Wysocki, Heikki Krogerus,
	Andy Shevchenko, Randy Dunlap, Dan Williams, Bartosz Golaszewski,
	linux-devicetree, lkml, linuxppc-dev, xen-devel, Nicolas Boichat,
	Jim Quinlan

On Wed, Mar 10, 2021 at 9:08 AM Will Deacon <will@kernel.org> wrote:
>
> Hi Claire,
>
> On Tue, Feb 09, 2021 at 02:21:30PM +0800, Claire Chang wrote:
> > Introduce the new compatible string, restricted-dma-pool, for restricted
> > DMA. One can specify the address and length of the restricted DMA memory
> > region by restricted-dma-pool in the reserved-memory node.
> >
> > Signed-off-by: Claire Chang <tientzu@chromium.org>
> > ---
> >  .../reserved-memory/reserved-memory.txt       | 24 +++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> > index e8d3096d922c..fc9a12c2f679 100644
> > --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> > +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> > @@ -51,6 +51,20 @@ compatible (optional) - standard definition
> >            used as a shared pool of DMA buffers for a set of devices. It can
> >            be used by an operating system to instantiate the necessary pool
> >            management subsystem if necessary.
> > +        - restricted-dma-pool: This indicates a region of memory meant to be
> > +          used as a pool of restricted DMA buffers for a set of devices. The
> > +          memory region would be the only region accessible to those devices.
> > +          When using this, the no-map and reusable properties must not be set,
> > +          so the operating system can create a virtual mapping that will be used
> > +          for synchronization. The main purpose for restricted DMA is to
> > +          mitigate the lack of DMA access control on systems without an IOMMU,
> > +          which could result in the DMA accessing the system memory at
> > +          unexpected times and/or unexpected addresses, possibly leading to data
> > +          leakage or corruption. The feature on its own provides 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 way to lock down
> > +          the memory access, e.g., MPU.
>
> As far as I can tell, these pools work with both static allocations (which
> seem to match your use-case where firmware has preconfigured the DMA ranges)
> but also with dynamic allocations where a 'size' property is present instead
> of the 'reg' property and the kernel is responsible for allocating the
> reservation during boot. Am I right and, if so, is that deliberate?

I believe so. I'm not keen on having size only reservations in DT.
Yes, we allowed that already, but that's back from the days of needing
large CMA carveouts to be reserved early in boot. I've read that the
kernel is much better now at contiguous allocations, so do we really
need this in DT anymore?

> I ask because I think that would potentially be useful to us for the
> Protected KVM work, where we need to bounce virtio memory accesses via
> guest-determined windows because the guest memory is generally inaccessible
> to the host. We've been hacking this using a combination of "swiotlb=force"
> and set_memory_{decrypted,encrypted}() but it would be much better to
> leverage the stuff you have here.
>
> Also:
>
> > +
> > +             restricted_dma_mem_reserved: restricted_dma_mem_reserved {
> > +                     compatible = "restricted-dma-pool";
> > +                     reg = <0x50000000 0x400000>;
> > +             };
> >       };
> >
> >       /* ... */
> > @@ -138,4 +157,9 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
> >               memory-region = <&multimedia_reserved>;
> >               /* ... */
> >       };
> > +
> > +     pcie_device: pcie_device@0,0 {
> > +             memory-region = <&restricted_dma_mem_reserved>;
> > +             /* ... */
> > +     };
>
> I find this example a bit weird, as I didn't think we usually had DT nodes
> for PCI devices; rather they are discovered as a result of probing config
> space. Is the idea that you have one reserved memory region attached to the
> RC and all the PCI devices below that share the region, or is there a need
> for a mapping mechanism?

We can have DT nodes for PCI. AIUI, IBM power systems always do. For
FDT, it's only if there are extra non-discoverable resources. It's
particularly fun when it's resources which need to be enabled for the
PCI device to be discovered. That seems to be a growing problem as PCI
becomes more common on embedded systems.

Rob


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool
  2021-03-10 21:40     ` Rob Herring
@ 2021-03-11  5:04       ` Florian Fainelli
  0 siblings, 0 replies; 23+ messages in thread
From: Florian Fainelli @ 2021-03-11  5:04 UTC (permalink / raw)
  To: Rob Herring, Will Deacon
  Cc: Claire Chang, Michael Ellerman, Joerg Roedel, Frank Rowand,
	Konrad Rzeszutek Wilk, Boris Ostrovsky, Juergen Gross,
	Christoph Hellwig, Marek Szyprowski, Benjamin Herrenschmidt,
	Paul Mackerras, list@263.net:IOMMU DRIVERS, Stefano Stabellini,
	Robin Murphy, Grant Likely, Heinrich Schuchardt, Thierry Reding,
	Ingo Molnar, Thiago Jung Bauermann, Peter Zijlstra, Greg KH,
	Saravana Kannan, Rafael J . Wysocki, Heikki Krogerus,
	Andy Shevchenko, Randy Dunlap, Dan Williams, Bartosz Golaszewski,
	linux-devicetree, lkml, linuxppc-dev, xen-devel, Nicolas Boichat,
	Jim Quinlan



On 3/10/2021 1:40 PM, Rob Herring wrote:
> On Wed, Mar 10, 2021 at 9:08 AM Will Deacon <will@kernel.org> wrote:
>>
>> Hi Claire,
>>
>> On Tue, Feb 09, 2021 at 02:21:30PM +0800, Claire Chang wrote:
>>> Introduce the new compatible string, restricted-dma-pool, for restricted
>>> DMA. One can specify the address and length of the restricted DMA memory
>>> region by restricted-dma-pool in the reserved-memory node.
>>>
>>> Signed-off-by: Claire Chang <tientzu@chromium.org>
>>> ---
>>>  .../reserved-memory/reserved-memory.txt       | 24 +++++++++++++++++++
>>>  1 file changed, 24 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
>>> index e8d3096d922c..fc9a12c2f679 100644
>>> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
>>> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
>>> @@ -51,6 +51,20 @@ compatible (optional) - standard definition
>>>            used as a shared pool of DMA buffers for a set of devices. It can
>>>            be used by an operating system to instantiate the necessary pool
>>>            management subsystem if necessary.
>>> +        - restricted-dma-pool: This indicates a region of memory meant to be
>>> +          used as a pool of restricted DMA buffers for a set of devices. The
>>> +          memory region would be the only region accessible to those devices.
>>> +          When using this, the no-map and reusable properties must not be set,
>>> +          so the operating system can create a virtual mapping that will be used
>>> +          for synchronization. The main purpose for restricted DMA is to
>>> +          mitigate the lack of DMA access control on systems without an IOMMU,
>>> +          which could result in the DMA accessing the system memory at
>>> +          unexpected times and/or unexpected addresses, possibly leading to data
>>> +          leakage or corruption. The feature on its own provides 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 way to lock down
>>> +          the memory access, e.g., MPU.
>>
>> As far as I can tell, these pools work with both static allocations (which
>> seem to match your use-case where firmware has preconfigured the DMA ranges)
>> but also with dynamic allocations where a 'size' property is present instead
>> of the 'reg' property and the kernel is responsible for allocating the
>> reservation during boot. Am I right and, if so, is that deliberate?
> 
> I believe so. I'm not keen on having size only reservations in DT.
> Yes, we allowed that already, but that's back from the days of needing
> large CMA carveouts to be reserved early in boot. I've read that the
> kernel is much better now at contiguous allocations, so do we really
> need this in DT anymore?

I would say yes, there can be a number of times where you want to semi
statically partition your physical memory and their reserved regions. Be
it to pack everything together under the same protection rules or
because you need to allocate memory from a particular address range in
say a non-uniform memory controller architecture where address windows
have different scheduling algorithms.
-- 
Florian


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v4 00/14] Restricted DMA
  2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
                   ` (13 preceding siblings ...)
  2021-02-09  6:21 ` [PATCH v4 14/14] of: Add plumbing for " Claire Chang
@ 2021-04-22  8:20 ` Claire Chang
  14 siblings, 0 replies; 23+ messages in thread
From: Claire Chang @ 2021-04-22  8:20 UTC (permalink / raw)
  To: Rob Herring, mpe, Joerg Roedel, Will Deacon, Frank Rowand,
	Konrad Rzeszutek Wilk, boris.ostrovsky, jgross,
	Christoph Hellwig, Marek Szyprowski
  Cc: benh, paulus, list@263.net:IOMMU DRIVERS, sstabellini,
	Robin Murphy, grant.likely, xypron.glpk, Thierry Reding, mingo,
	bauerman, peterz, Greg KH, Saravana Kannan, Rafael J . Wysocki,
	heikki.krogerus, Andy Shevchenko, Randy Dunlap, Dan Williams,
	Bartosz Golaszewski, linux-devicetree, lkml, linuxppc-dev,
	xen-devel, Nicolas Boichat, Jim Quinlan

v5 here: https://lore.kernel.org/patchwork/cover/1416899/ to rebase
onto Christoph's swiotlb cleanups.


^ permalink raw reply	[flat|nested] 23+ messages in thread

end of thread, other threads:[~2021-04-22  8:21 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-09  6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
2021-02-09  6:21 ` [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start Claire Chang
2021-02-09  8:40   ` Christoph Hellwig
2021-02-09  6:21 ` [PATCH v4 02/14] swiotlb: Move is_swiotlb_buffer() to swiotlb.c Claire Chang
2021-02-09  6:21 ` [PATCH v4 03/14] swiotlb: Add struct swiotlb Claire Chang
2021-02-09  6:21 ` [PATCH v4 04/14] swiotlb: Refactor swiotlb_late_init_with_tbl Claire Chang
2021-02-09  6:21 ` [PATCH v4 05/14] swiotlb: Add DMA_RESTRICTED_POOL Claire Chang
2021-02-09  6:21 ` [PATCH v4 06/14] swiotlb: Add restricted DMA pool Claire Chang
2021-02-09  6:21 ` [PATCH v4 07/14] swiotlb: Update swiotlb API to gain a struct device argument Claire Chang
2021-02-09  6:21 ` [PATCH v4 08/14] swiotlb: Use restricted DMA pool if available Claire Chang
2021-02-09  6:21 ` [PATCH v4 09/14] swiotlb: Refactor swiotlb_tbl_{map,unmap}_single Claire Chang
2021-02-09  6:21 ` [PATCH v4 10/14] dma-direct: Add a new wrapper __dma_direct_free_pages() Claire Chang
2021-02-09  6:21 ` [PATCH v4 11/14] swiotlb: Add is_dev_swiotlb_force() Claire Chang
2021-02-09  6:21 ` [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-02-26  4:17   ` Claire Chang
2021-02-26  5:17     ` Christoph Hellwig
2021-02-26  9:35       ` Claire Chang
2021-02-09  6:21 ` [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-03-10 16:07   ` Will Deacon
2021-03-10 21:40     ` Rob Herring
2021-03-11  5:04       ` Florian Fainelli
2021-02-09  6:21 ` [PATCH v4 14/14] of: Add plumbing for " Claire Chang
2021-04-22  8:20 ` [PATCH v4 00/14] Restricted DMA Claire Chang

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