cleanup swiotlb initialization

cleanup swiotlb initialization

[Christoph Hellwig]

Hi all,

this series tries to clean up the swiotlb initialization, including
that of swiotlb-xen.  To get there is also removes the x86 iommu table
infrastructure that massively obsfucates the initialization path.

Git tree:

    git://git.infradead.org/users/hch/misc.git swiotlb-init-cleanup

Gitweb:

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

Diffstat:
 arch/ia64/include/asm/iommu_table.h      |    7 -
 arch/x86/include/asm/iommu_table.h       |  102 -------------------
 arch/x86/include/asm/swiotlb.h           |   30 -----
 arch/x86/kernel/pci-iommu_table.c        |   77 --------------
 arch/x86/kernel/pci-swiotlb.c            |   77 --------------
 arch/x86/xen/pci-swiotlb-xen.c           |   96 ------------------
 b/arch/arm/mm/init.c                     |    6 -
 b/arch/arm/xen/mm.c                      |   23 ++--
 b/arch/arm64/mm/init.c                   |    6 -
 b/arch/ia64/mm/init.c                    |    4 
 b/arch/mips/cavium-octeon/dma-octeon.c   |   15 --
 b/arch/mips/loongson64/dma.c             |    2 
 b/arch/mips/pci/pci-octeon.c             |    2 
 b/arch/mips/sibyte/common/dma.c          |    2 
 b/arch/powerpc/include/asm/svm.h         |    4 
 b/arch/powerpc/include/asm/swiotlb.h     |    1 
 b/arch/powerpc/mm/mem.c                  |    6 -
 b/arch/powerpc/platforms/pseries/setup.c |    3 
 b/arch/powerpc/platforms/pseries/svm.c   |   26 ----
 b/arch/riscv/mm/init.c                   |    8 -
 b/arch/s390/mm/init.c                    |    3 
 b/arch/x86/include/asm/dma-mapping.h     |   12 --
 b/arch/x86/include/asm/gart.h            |    5 
 b/arch/x86/include/asm/iommu.h           |    8 +
 b/arch/x86/include/asm/xen/page.h        |    5 
 b/arch/x86/include/asm/xen/swiotlb-xen.h |    2 
 b/arch/x86/kernel/Makefile               |    2 
 b/arch/x86/kernel/amd_gart_64.c          |    5 
 b/arch/x86/kernel/aperture_64.c          |   14 --
 b/arch/x86/kernel/cpu/mshyperv.c         |    8 -
 b/arch/x86/kernel/pci-dma.c              |  114 +++++++++++++++++----
 b/arch/x86/kernel/tboot.c                |    1 
 b/arch/x86/kernel/vmlinux.lds.S          |   12 --
 b/arch/x86/mm/mem_encrypt_amd.c          |    3 
 b/arch/x86/pci/sta2x11-fixup.c           |    2 
 b/arch/x86/xen/Makefile                  |    2 
 b/drivers/iommu/amd/init.c               |    6 -
 b/drivers/iommu/amd/iommu.c              |    5 
 b/drivers/iommu/intel/dmar.c             |    6 -
 b/drivers/xen/swiotlb-xen.c              |  132 -------------------------
 b/include/linux/dmar.h                   |    6 -
 b/include/linux/swiotlb.h                |   22 ++--
 b/include/trace/events/swiotlb.h         |   29 +----
 b/include/xen/arm/page.h                 |    1 
 b/include/xen/swiotlb-xen.h              |    8 +
 b/kernel/dma/direct.h                    |    2 
 b/kernel/dma/swiotlb.c                   |  163 +++++++++++++++----------------
 47 files changed, 258 insertions(+), 817 deletions(-)

[PATCH 01/11] dma-direct: use is_swiotlb_active in dma_direct_map_page

[Christoph Hellwig]

Use the more specific is_swiotlb_active check instead of checking the
global swiotlb_force variable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/dma/direct.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index 4632b0f4f72eb..4dc16e08c7e1a 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h
@@ -91,7 +91,7 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev,
 		return swiotlb_map(dev, phys, size, dir, attrs);
 
 	if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
-		if (swiotlb_force != SWIOTLB_NO_FORCE)
+		if (is_swiotlb_active(dev))
 			return swiotlb_map(dev, phys, size, dir, attrs);
 
 		dev_WARN_ONCE(dev, 1,
-- 
2.30.2

Re: [PATCH 01/11] dma-direct: use is_swiotlb_active in dma_direct_map_page

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> Use the more specific is_swiotlb_active check instead of checking the
> global swiotlb_force variable.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  kernel/dma/direct.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
> index 4632b0f4f72eb..4dc16e08c7e1a 100644
> --- a/kernel/dma/direct.h
> +++ b/kernel/dma/direct.h
> @@ -91,7 +91,7 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev,
>  		return swiotlb_map(dev, phys, size, dir, attrs);
>  
>  	if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
> -		if (swiotlb_force != SWIOTLB_NO_FORCE)
> +		if (is_swiotlb_active(dev))
>  			return swiotlb_map(dev, phys, size, dir, attrs);
>  
>  		dev_WARN_ONCE(dev, 1,
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

[PATCH 02/11] swiotlb: make swiotlb_exit a no-op if SWIOTLB_FORCE is set

[Christoph Hellwig]

If force bouncing is enabled we can't release the bufffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/dma/swiotlb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index f1e7ea160b433..36fbf1181d285 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -378,6 +378,9 @@ void __init swiotlb_exit(void)
 	unsigned long tbl_vaddr;
 	size_t tbl_size, slots_size;
 
+	if (swiotlb_force == SWIOTLB_FORCE)
+		return;
+
 	if (!mem->nslabs)
 		return;
 
-- 
2.30.2

Re: [PATCH 02/11] swiotlb: make swiotlb_exit a no-op if SWIOTLB_FORCE is set

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> If force bouncing is enabled we can't release the bufffers.

typo							^^^^

> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  kernel/dma/swiotlb.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index f1e7ea160b433..36fbf1181d285 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -378,6 +378,9 @@ void __init swiotlb_exit(void)
>  	unsigned long tbl_vaddr;
>  	size_t tbl_size, slots_size;
>  
> +	if (swiotlb_force == SWIOTLB_FORCE)
> +		return;
> +
>  	if (!mem->nslabs)
>  		return;
>  
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

[PATCH 03/11] swiotlb: simplify swiotlb_max_segment

[Christoph Hellwig]

Remove the bogus Xen override that was usually larger than the actual
size and just calculate the value on demand.  Note that
swiotlb_max_segment still doesn't make sense as an interface and should
eventually be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/xen/swiotlb-xen.c |  2 --
 include/linux/swiotlb.h   |  1 -
 kernel/dma/swiotlb.c      | 20 +++-----------------
 3 files changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 47aebd98f52f5..485cd06ed39e7 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -202,7 +202,6 @@ int xen_swiotlb_init(void)
 	rc = swiotlb_late_init_with_tbl(start, nslabs);
 	if (rc)
 		return rc;
-	swiotlb_set_max_segment(PAGE_SIZE);
 	return 0;
 error:
 	if (nslabs > 1024 && repeat--) {
@@ -254,7 +253,6 @@ void __init xen_swiotlb_init_early(void)
 
 	if (swiotlb_init_with_tbl(start, nslabs, true))
 		panic("Cannot allocate SWIOTLB buffer");
-	swiotlb_set_max_segment(PAGE_SIZE);
 }
 #endif /* CONFIG_X86 */
 
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index f6c3638255d54..9fb3a568f0c51 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -164,7 +164,6 @@ static inline void swiotlb_adjust_size(unsigned long size)
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
-extern void swiotlb_set_max_segment(unsigned int);
 
 #ifdef CONFIG_DMA_RESTRICTED_POOL
 struct page *swiotlb_alloc(struct device *dev, size_t size);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 36fbf1181d285..519e363097190 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -75,12 +75,6 @@ struct io_tlb_mem io_tlb_default_mem;
 
 phys_addr_t swiotlb_unencrypted_base;
 
-/*
- * Max segment that we can provide which (if pages are contingous) will
- * not be bounced (unless SWIOTLB_FORCE is set).
- */
-static unsigned int max_segment;
-
 static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
 
 static int __init
@@ -104,18 +98,12 @@ early_param("swiotlb", setup_io_tlb_npages);
 
 unsigned int swiotlb_max_segment(void)
 {
-	return io_tlb_default_mem.nslabs ? max_segment : 0;
+	if (!io_tlb_default_mem.nslabs)
+		return 0;
+	return rounddown(io_tlb_default_mem.nslabs << IO_TLB_SHIFT, PAGE_SIZE);
 }
 EXPORT_SYMBOL_GPL(swiotlb_max_segment);
 
-void swiotlb_set_max_segment(unsigned int val)
-{
-	if (swiotlb_force == SWIOTLB_FORCE)
-		max_segment = 1;
-	else
-		max_segment = rounddown(val, PAGE_SIZE);
-}
-
 unsigned long swiotlb_size_or_default(void)
 {
 	return default_nslabs << IO_TLB_SHIFT;
@@ -267,7 +255,6 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 
 	if (verbose)
 		swiotlb_print_info();
-	swiotlb_set_max_segment(mem->nslabs << IO_TLB_SHIFT);
 	return 0;
 }
 
@@ -368,7 +355,6 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	swiotlb_init_io_tlb_mem(mem, virt_to_phys(tlb), nslabs, true);
 
 	swiotlb_print_info();
-	swiotlb_set_max_segment(mem->nslabs << IO_TLB_SHIFT);
 	return 0;
 }
 
-- 
2.30.2

Re: [PATCH 03/11] swiotlb: simplify swiotlb_max_segment

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> Remove the bogus Xen override that was usually larger than the actual
> size and just calculate the value on demand.  Note that
> swiotlb_max_segment still doesn't make sense as an interface and should
> eventually be removed.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/xen/swiotlb-xen.c |  2 --
>  include/linux/swiotlb.h   |  1 -
>  kernel/dma/swiotlb.c      | 20 +++-----------------
>  3 files changed, 3 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 47aebd98f52f5..485cd06ed39e7 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -202,7 +202,6 @@ int xen_swiotlb_init(void)
>  	rc = swiotlb_late_init_with_tbl(start, nslabs);
>  	if (rc)
>  		return rc;
> -	swiotlb_set_max_segment(PAGE_SIZE);
>  	return 0;
>  error:
>  	if (nslabs > 1024 && repeat--) {
> @@ -254,7 +253,6 @@ void __init xen_swiotlb_init_early(void)
>  
>  	if (swiotlb_init_with_tbl(start, nslabs, true))
>  		panic("Cannot allocate SWIOTLB buffer");
> -	swiotlb_set_max_segment(PAGE_SIZE);
>  }
>  #endif /* CONFIG_X86 */
>  
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index f6c3638255d54..9fb3a568f0c51 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -164,7 +164,6 @@ static inline void swiotlb_adjust_size(unsigned long size)
>  #endif /* CONFIG_SWIOTLB */
>  
>  extern void swiotlb_print_info(void);
> -extern void swiotlb_set_max_segment(unsigned int);
>  
>  #ifdef CONFIG_DMA_RESTRICTED_POOL
>  struct page *swiotlb_alloc(struct device *dev, size_t size);
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 36fbf1181d285..519e363097190 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -75,12 +75,6 @@ struct io_tlb_mem io_tlb_default_mem;
>  
>  phys_addr_t swiotlb_unencrypted_base;
>  
> -/*
> - * Max segment that we can provide which (if pages are contingous) will
> - * not be bounced (unless SWIOTLB_FORCE is set).
> - */
> -static unsigned int max_segment;
> -
>  static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
>  
>  static int __init
> @@ -104,18 +98,12 @@ early_param("swiotlb", setup_io_tlb_npages);
>  
>  unsigned int swiotlb_max_segment(void)
>  {
> -	return io_tlb_default_mem.nslabs ? max_segment : 0;
> +	if (!io_tlb_default_mem.nslabs)
> +		return 0;
> +	return rounddown(io_tlb_default_mem.nslabs << IO_TLB_SHIFT, PAGE_SIZE);
>  }
>  EXPORT_SYMBOL_GPL(swiotlb_max_segment);
>  
> -void swiotlb_set_max_segment(unsigned int val)
> -{
> -	if (swiotlb_force == SWIOTLB_FORCE)
> -		max_segment = 1;
> -	else
> -		max_segment = rounddown(val, PAGE_SIZE);
> -}
> -
>  unsigned long swiotlb_size_or_default(void)
>  {
>  	return default_nslabs << IO_TLB_SHIFT;
> @@ -267,7 +255,6 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
>  
>  	if (verbose)
>  		swiotlb_print_info();
> -	swiotlb_set_max_segment(mem->nslabs << IO_TLB_SHIFT);
>  	return 0;
>  }
>  
> @@ -368,7 +355,6 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
>  	swiotlb_init_io_tlb_mem(mem, virt_to_phys(tlb), nslabs, true);
>  
>  	swiotlb_print_info();
> -	swiotlb_set_max_segment(mem->nslabs << IO_TLB_SHIFT);
>  	return 0;
>  }
>  

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

[PATCH 04/11] swiotlb: rename swiotlb_late_init_with_default_size

[Christoph Hellwig]

swiotlb_late_init_with_default_size is an overly verbose name that
doesn't even catch what the function is doing, given that the size is
not just a default but the actual requested size.

Rename it to swiotlb_init_late.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/pci/sta2x11-fixup.c | 2 +-
 include/linux/swiotlb.h      | 2 +-
 kernel/dma/swiotlb.c         | 6 ++----
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index 101081ad64b6d..e0c039a75b2db 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev)
 		int size = STA2X11_SWIOTLB_SIZE;
 		/* First instance: register your own swiotlb area */
 		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
-		if (swiotlb_late_init_with_default_size(size))
+		if (swiotlb_init_late(size))
 			dev_emerg(&pdev->dev, "init swiotlb failed\n");
 	}
 	list_add(&instance->list, &sta2x11_instance_list);
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 9fb3a568f0c51..b48b26bfa0edb 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -40,7 +40,7 @@ extern void swiotlb_init(int verbose);
 int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
 unsigned long swiotlb_size_or_default(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
-extern int swiotlb_late_init_with_default_size(size_t default_size);
+int swiotlb_init_late(size_t size);
 extern void __init swiotlb_update_mem_attributes(void);
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 519e363097190..5f64b02fbb732 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -290,11 +290,9 @@ swiotlb_init(int verbose)
  * initialize the swiotlb later using the slab allocator if needed.
  * This should be just like above, but with some error catching.
  */
-int
-swiotlb_late_init_with_default_size(size_t default_size)
+int swiotlb_init_late(size_t size)
 {
-	unsigned long nslabs =
-		ALIGN(default_size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
+	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
 	unsigned long bytes;
 	unsigned char *vstart = NULL;
 	unsigned int order;
-- 
2.30.2

Re: [PATCH 04/11] swiotlb: rename swiotlb_late_init_with_default_size

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> swiotlb_late_init_with_default_size is an overly verbose name that
> doesn't even catch what the function is doing, given that the size is
> not just a default but the actual requested size.
> 
> Rename it to swiotlb_init_late.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/x86/pci/sta2x11-fixup.c | 2 +-
>  include/linux/swiotlb.h      | 2 +-
>  kernel/dma/swiotlb.c         | 6 ++----
>  3 files changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
> index 101081ad64b6d..e0c039a75b2db 100644
> --- a/arch/x86/pci/sta2x11-fixup.c
> +++ b/arch/x86/pci/sta2x11-fixup.c
> @@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev)
>  		int size = STA2X11_SWIOTLB_SIZE;
>  		/* First instance: register your own swiotlb area */
>  		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
> -		if (swiotlb_late_init_with_default_size(size))
> +		if (swiotlb_init_late(size))
>  			dev_emerg(&pdev->dev, "init swiotlb failed\n");
>  	}
>  	list_add(&instance->list, &sta2x11_instance_list);
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 9fb3a568f0c51..b48b26bfa0edb 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -40,7 +40,7 @@ extern void swiotlb_init(int verbose);
>  int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
>  unsigned long swiotlb_size_or_default(void);
>  extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
> -extern int swiotlb_late_init_with_default_size(size_t default_size);
> +int swiotlb_init_late(size_t size);
>  extern void __init swiotlb_update_mem_attributes(void);
>  
>  phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 519e363097190..5f64b02fbb732 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -290,11 +290,9 @@ swiotlb_init(int verbose)
>   * initialize the swiotlb later using the slab allocator if needed.
>   * This should be just like above, but with some error catching.
>   */
> -int
> -swiotlb_late_init_with_default_size(size_t default_size)
> +int swiotlb_init_late(size_t size)
>  {
> -	unsigned long nslabs =
> -		ALIGN(default_size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
> +	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
>  	unsigned long bytes;
>  	unsigned char *vstart = NULL;
>  	unsigned int order;
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

[PATCH 05/11] swiotlb: pass a gfp_mask argument to swiotlb_init_late

[Christoph Hellwig]

Let the caller chose a zone to allocate from.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/pci/sta2x11-fixup.c | 2 +-
 include/linux/swiotlb.h      | 2 +-
 kernel/dma/swiotlb.c         | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index e0c039a75b2db..c7e6faf59a861 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev)
 		int size = STA2X11_SWIOTLB_SIZE;
 		/* First instance: register your own swiotlb area */
 		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
-		if (swiotlb_init_late(size))
+		if (swiotlb_init_late(size, GFP_DMA))
 			dev_emerg(&pdev->dev, "init swiotlb failed\n");
 	}
 	list_add(&instance->list, &sta2x11_instance_list);
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index b48b26bfa0edb..1befd6b2ccf5e 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -40,7 +40,7 @@ extern void swiotlb_init(int verbose);
 int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
 unsigned long swiotlb_size_or_default(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
-int swiotlb_init_late(size_t size);
+int swiotlb_init_late(size_t size, gfp_t gfp_mask);
 extern void __init swiotlb_update_mem_attributes(void);
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 5f64b02fbb732..a653fcf1fe6c2 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -290,7 +290,7 @@ swiotlb_init(int verbose)
  * initialize the swiotlb later using the slab allocator if needed.
  * This should be just like above, but with some error catching.
  */
-int swiotlb_init_late(size_t size)
+int swiotlb_init_late(size_t size, gfp_t gfp_mask)
 {
 	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
 	unsigned long bytes;
@@ -309,7 +309,7 @@ int swiotlb_init_late(size_t size)
 	bytes = nslabs << IO_TLB_SHIFT;
 
 	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
-		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
+		vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
 						  order);
 		if (vstart)
 			break;
-- 
2.30.2

Re: [PATCH 05/11] swiotlb: pass a gfp_mask argument to swiotlb_init_late

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> Let the caller chose a zone to allocate from.

This is being used later via xen_swiotlb_gfp() on arm platform.

> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/x86/pci/sta2x11-fixup.c | 2 +-
>  include/linux/swiotlb.h      | 2 +-
>  kernel/dma/swiotlb.c         | 4 ++--
>  3 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
> index e0c039a75b2db..c7e6faf59a861 100644
> --- a/arch/x86/pci/sta2x11-fixup.c
> +++ b/arch/x86/pci/sta2x11-fixup.c
> @@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev)
>  		int size = STA2X11_SWIOTLB_SIZE;
>  		/* First instance: register your own swiotlb area */
>  		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
> -		if (swiotlb_init_late(size))
> +		if (swiotlb_init_late(size, GFP_DMA))
>  			dev_emerg(&pdev->dev, "init swiotlb failed\n");
>  	}
>  	list_add(&instance->list, &sta2x11_instance_list);
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index b48b26bfa0edb..1befd6b2ccf5e 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -40,7 +40,7 @@ extern void swiotlb_init(int verbose);
>  int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
>  unsigned long swiotlb_size_or_default(void);
>  extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
> -int swiotlb_init_late(size_t size);
> +int swiotlb_init_late(size_t size, gfp_t gfp_mask);
>  extern void __init swiotlb_update_mem_attributes(void);
>  
>  phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 5f64b02fbb732..a653fcf1fe6c2 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -290,7 +290,7 @@ swiotlb_init(int verbose)
>   * initialize the swiotlb later using the slab allocator if needed.
>   * This should be just like above, but with some error catching.
>   */
> -int swiotlb_init_late(size_t size)
> +int swiotlb_init_late(size_t size, gfp_t gfp_mask)
>  {
>  	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
>  	unsigned long bytes;
> @@ -309,7 +309,7 @@ int swiotlb_init_late(size_t size)
>  	bytes = nslabs << IO_TLB_SHIFT;
>  
>  	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
> -		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
> +		vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
>  						  order);
>  		if (vstart)
>  			break;
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

[PATCH 06/11] MIPS/octeon: use swiotlb_init instead of open coding it

[Christoph Hellwig]

Use the generic swiotlb initialization helper instead of open coding it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/mips/cavium-octeon/dma-octeon.c | 15 ++-------------
 arch/mips/pci/pci-octeon.c           |  2 +-
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
index df70308db0e69..fb7547e217263 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -186,15 +186,12 @@ phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
 	return daddr;
 }
 
-char *octeon_swiotlb;
-
 void __init plat_swiotlb_setup(void)
 {
 	phys_addr_t start, end;
 	phys_addr_t max_addr;
 	phys_addr_t addr_size;
 	size_t swiotlbsize;
-	unsigned long swiotlb_nslabs;
 	u64 i;
 
 	max_addr = 0;
@@ -236,15 +233,7 @@ void __init plat_swiotlb_setup(void)
 	if (OCTEON_IS_OCTEON2() && max_addr >= 0x100000000ul)
 		swiotlbsize = 64 * (1<<20);
 #endif
-	swiotlb_nslabs = swiotlbsize >> IO_TLB_SHIFT;
-	swiotlb_nslabs = ALIGN(swiotlb_nslabs, IO_TLB_SEGSIZE);
-	swiotlbsize = swiotlb_nslabs << IO_TLB_SHIFT;
-
-	octeon_swiotlb = memblock_alloc_low(swiotlbsize, PAGE_SIZE);
-	if (!octeon_swiotlb)
-		panic("%s: Failed to allocate %zu bytes align=%lx\n",
-		      __func__, swiotlbsize, PAGE_SIZE);
 
-	if (swiotlb_init_with_tbl(octeon_swiotlb, swiotlb_nslabs, 1) == -ENOMEM)
-		panic("Cannot allocate SWIOTLB buffer");
+	swiotlb_adjust_size(swiotlbsize);
+	swiotlb_init(1);
 }
diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index fc29b85cfa926..e457a18cbdc59 100644
--- a/arch/mips/pci/pci-octeon.c
+++ b/arch/mips/pci/pci-octeon.c
@@ -664,7 +664,7 @@ static int __init octeon_pci_setup(void)
 
 		/* BAR1 movable regions contiguous to cover the swiotlb */
 		octeon_bar1_pci_phys =
-			virt_to_phys(octeon_swiotlb) & ~((1ull << 22) - 1);
+			io_tlb_default_mem.start & ~((1ull << 22) - 1);
 
 		for (index = 0; index < 32; index++) {
 			union cvmx_pci_bar1_indexx bar1_index;
-- 
2.30.2

[PATCH 07/11] x86: remove the IOMMU table infrastructure

[Christoph Hellwig]

The IOMMU table tries to separate the different IOMMUs into different
backends, but actually requires various cross calls.

Rewrite the code to do the generic swiotlb/swiotlb-xen setup directly
in pci-dma.c and then just call into the IOMMU drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/ia64/include/asm/iommu_table.h    |   7 --
 arch/x86/include/asm/dma-mapping.h     |   1 -
 arch/x86/include/asm/gart.h            |   5 +-
 arch/x86/include/asm/iommu.h           |   6 ++
 arch/x86/include/asm/iommu_table.h     | 102 ----------------------
 arch/x86/include/asm/swiotlb.h         |  30 -------
 arch/x86/include/asm/xen/swiotlb-xen.h |   2 -
 arch/x86/kernel/Makefile               |   2 -
 arch/x86/kernel/amd_gart_64.c          |   5 +-
 arch/x86/kernel/aperture_64.c          |  14 ++--
 arch/x86/kernel/pci-dma.c              | 112 ++++++++++++++++++++-----
 arch/x86/kernel/pci-iommu_table.c      |  77 -----------------
 arch/x86/kernel/pci-swiotlb.c          |  77 -----------------
 arch/x86/kernel/tboot.c                |   1 -
 arch/x86/kernel/vmlinux.lds.S          |  12 ---
 arch/x86/xen/Makefile                  |   2 -
 arch/x86/xen/pci-swiotlb-xen.c         |  96 ---------------------
 drivers/iommu/amd/init.c               |   6 --
 drivers/iommu/amd/iommu.c              |   5 +-
 drivers/iommu/intel/dmar.c             |   6 +-
 include/linux/dmar.h                   |   6 +-
 21 files changed, 115 insertions(+), 459 deletions(-)
 delete mode 100644 arch/ia64/include/asm/iommu_table.h
 delete mode 100644 arch/x86/include/asm/iommu_table.h
 delete mode 100644 arch/x86/include/asm/swiotlb.h
 delete mode 100644 arch/x86/kernel/pci-iommu_table.c
 delete mode 100644 arch/x86/kernel/pci-swiotlb.c
 delete mode 100644 arch/x86/xen/pci-swiotlb-xen.c

diff --git a/arch/ia64/include/asm/iommu_table.h b/arch/ia64/include/asm/iommu_table.h
deleted file mode 100644
index cc96116ac276a..0000000000000
--- a/arch/ia64/include/asm/iommu_table.h
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_IA64_IOMMU_TABLE_H
-#define _ASM_IA64_IOMMU_TABLE_H
-
-#define IOMMU_INIT_POST(_detect)
-
-#endif /* _ASM_IA64_IOMMU_TABLE_H */
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index bb1654fe0ce74..256fd8115223d 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -9,7 +9,6 @@
 
 #include <linux/scatterlist.h>
 #include <asm/io.h>
-#include <asm/swiotlb.h>
 
 extern int iommu_merge;
 extern int panic_on_overflow;
diff --git a/arch/x86/include/asm/gart.h b/arch/x86/include/asm/gart.h
index 3185565743459..5af8088a10df6 100644
--- a/arch/x86/include/asm/gart.h
+++ b/arch/x86/include/asm/gart.h
@@ -38,7 +38,7 @@ extern int gart_iommu_aperture_disabled;
 extern void early_gart_iommu_check(void);
 extern int gart_iommu_init(void);
 extern void __init gart_parse_options(char *);
-extern int gart_iommu_hole_init(void);
+void gart_iommu_hole_init(void);
 
 #else
 #define gart_iommu_aperture            0
@@ -51,9 +51,8 @@ static inline void early_gart_iommu_check(void)
 static inline void gart_parse_options(char *options)
 {
 }
-static inline int gart_iommu_hole_init(void)
+static inline void gart_iommu_hole_init(void)
 {
-	return -ENODEV;
 }
 #endif
 
diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index bf1ed2ddc74bd..dba89ed40d38d 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -9,6 +9,12 @@
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
 
+#ifdef CONFIG_SWIOTLB
+extern bool x86_swiotlb_enable;
+#else
+#define x86_swiotlb_enable false
+#endif
+
 /* 10 seconds */
 #define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
 
diff --git a/arch/x86/include/asm/iommu_table.h b/arch/x86/include/asm/iommu_table.h
deleted file mode 100644
index 1fb3fd1a83c25..0000000000000
--- a/arch/x86/include/asm/iommu_table.h
+++ /dev/null
@@ -1,102 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_IOMMU_TABLE_H
-#define _ASM_X86_IOMMU_TABLE_H
-
-#include <asm/swiotlb.h>
-
-/*
- * History lesson:
- * The execution chain of IOMMUs in 2.6.36 looks as so:
- *
- *            [xen-swiotlb]
- *                 |
- *         +----[swiotlb *]--+
- *        /         |         \
- *       /          |          \
- *    [GART]     [Calgary]  [Intel VT-d]
- *     /
- *    /
- * [AMD-Vi]
- *
- * *: if SWIOTLB detected 'iommu=soft'/'swiotlb=force' it would skip
- * over the rest of IOMMUs and unconditionally initialize the SWIOTLB.
- * Also it would surreptitiously initialize set the swiotlb=1 if there were
- * more than 4GB and if the user did not pass in 'iommu=off'. The swiotlb
- * flag would be turned off by all IOMMUs except the Calgary one.
- *
- * The IOMMU_INIT* macros allow a similar tree (or more complex if desired)
- * to be built by defining who we depend on.
- *
- * And all that needs to be done is to use one of the macros in the IOMMU
- * and the pci-dma.c will take care of the rest.
- */
-
-struct iommu_table_entry {
-	initcall_t	detect;
-	initcall_t	depend;
-	void		(*early_init)(void); /* No memory allocate available. */
-	void		(*late_init)(void); /* Yes, can allocate memory. */
-#define IOMMU_FINISH_IF_DETECTED (1<<0)
-#define IOMMU_DETECTED		 (1<<1)
-	int		flags;
-};
-/*
- * Macro fills out an entry in the .iommu_table that is equivalent
- * to the fields that 'struct iommu_table_entry' has. The entries
- * that are put in the .iommu_table section are not put in any order
- * hence during boot-time we will have to resort them based on
- * dependency. */
-
-
-#define __IOMMU_INIT(_detect, _depend, _early_init, _late_init, _finish)\
-	static const struct iommu_table_entry				\
-		__iommu_entry_##_detect __used				\
-	__attribute__ ((unused, __section__(".iommu_table"),		\
-			aligned((sizeof(void *)))))	\
-	= {_detect, _depend, _early_init, _late_init,			\
-	   _finish ? IOMMU_FINISH_IF_DETECTED : 0}
-/*
- * The simplest IOMMU definition. Provide the detection routine
- * and it will be run after the SWIOTLB and the other IOMMUs
- * that utilize this macro. If the IOMMU is detected (ie, the
- * detect routine returns a positive value), the other IOMMUs
- * are also checked. You can use IOMMU_INIT_POST_FINISH if you prefer
- * to stop detecting the other IOMMUs after yours has been detected.
- */
-#define IOMMU_INIT_POST(_detect)					\
-	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  NULL, NULL, 0)
-
-#define IOMMU_INIT_POST_FINISH(detect)					\
-	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  NULL, NULL, 1)
-
-/*
- * A more sophisticated version of IOMMU_INIT. This variant requires:
- *  a). A detection routine function.
- *  b). The name of the detection routine we depend on to get called
- *      before us.
- *  c). The init routine which gets called if the detection routine
- *      returns a positive value from the pci_iommu_alloc. This means
- *      no presence of a memory allocator.
- *  d). Similar to the 'init', except that this gets called from pci_iommu_init
- *      where we do have a memory allocator.
- *
- * The standard IOMMU_INIT differs from the IOMMU_INIT_FINISH variant
- * in that the former will continue detecting other IOMMUs in the call
- * list after the detection routine returns a positive number, while the
- * latter will stop the execution chain upon first successful detection.
- * Both variants will still call the 'init' and 'late_init' functions if
- * they are set.
- */
-#define IOMMU_INIT_FINISH(_detect, _depend, _init, _late_init)		\
-	__IOMMU_INIT(_detect, _depend, _init, _late_init, 1)
-
-#define IOMMU_INIT(_detect, _depend, _init, _late_init)			\
-	__IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
-
-void sort_iommu_table(struct iommu_table_entry *start,
-		      struct iommu_table_entry *finish);
-
-void check_iommu_entries(struct iommu_table_entry *start,
-			 struct iommu_table_entry *finish);
-
-#endif /* _ASM_X86_IOMMU_TABLE_H */
diff --git a/arch/x86/include/asm/swiotlb.h b/arch/x86/include/asm/swiotlb.h
deleted file mode 100644
index ff6c92eff035a..0000000000000
--- a/arch/x86/include/asm/swiotlb.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_SWIOTLB_H
-#define _ASM_X86_SWIOTLB_H
-
-#include <linux/swiotlb.h>
-
-#ifdef CONFIG_SWIOTLB
-extern int swiotlb;
-extern int __init pci_swiotlb_detect_override(void);
-extern int __init pci_swiotlb_detect_4gb(void);
-extern void __init pci_swiotlb_init(void);
-extern void __init pci_swiotlb_late_init(void);
-#else
-#define swiotlb 0
-static inline int pci_swiotlb_detect_override(void)
-{
-	return 0;
-}
-static inline int pci_swiotlb_detect_4gb(void)
-{
-	return 0;
-}
-static inline void pci_swiotlb_init(void)
-{
-}
-static inline void pci_swiotlb_late_init(void)
-{
-}
-#endif
-#endif /* _ASM_X86_SWIOTLB_H */
diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h
index 66b4ddde77430..e5a90b42e4dde 100644
--- a/arch/x86/include/asm/xen/swiotlb-xen.h
+++ b/arch/x86/include/asm/xen/swiotlb-xen.h
@@ -3,10 +3,8 @@
 #define _ASM_X86_SWIOTLB_XEN_H
 
 #ifdef CONFIG_SWIOTLB_XEN
-extern int __init pci_xen_swiotlb_detect(void);
 extern int pci_xen_swiotlb_init_late(void);
 #else
-#define pci_xen_swiotlb_detect NULL
 static inline int pci_xen_swiotlb_init_late(void) { return -ENXIO; }
 #endif
 
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 6aef9ee28a394..2851d4f0aa0d2 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -71,7 +71,6 @@ obj-y			+= bootflag.o e820.o
 obj-y			+= pci-dma.o quirks.o topology.o kdebugfs.o
 obj-y			+= alternative.o i8253.o hw_breakpoint.o
 obj-y			+= tsc.o tsc_msr.o io_delay.o rtc.o
-obj-y			+= pci-iommu_table.o
 obj-y			+= resource.o
 obj-y			+= irqflags.o
 obj-y			+= static_call.o
@@ -136,7 +135,6 @@ obj-$(CONFIG_PCSPKR_PLATFORM)	+= pcspeaker.o
 
 obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
 
-obj-$(CONFIG_SWIOTLB)			+= pci-swiotlb.o
 obj-$(CONFIG_OF)			+= devicetree.o
 obj-$(CONFIG_UPROBES)			+= uprobes.o
 
diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index ed837383de5c8..194d54eed5376 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -38,11 +38,9 @@
 #include <asm/iommu.h>
 #include <asm/gart.h>
 #include <asm/set_memory.h>
-#include <asm/swiotlb.h>
 #include <asm/dma.h>
 #include <asm/amd_nb.h>
 #include <asm/x86_init.h>
-#include <asm/iommu_table.h>
 
 static unsigned long iommu_bus_base;	/* GART remapping area (physical) */
 static unsigned long iommu_size;	/* size of remapping area bytes */
@@ -808,7 +806,7 @@ int __init gart_iommu_init(void)
 	flush_gart();
 	dma_ops = &gart_dma_ops;
 	x86_platform.iommu_shutdown = gart_iommu_shutdown;
-	swiotlb = 0;
+	x86_swiotlb_enable = false;
 
 	return 0;
 }
@@ -842,4 +840,3 @@ void __init gart_parse_options(char *p)
 		}
 	}
 }
-IOMMU_INIT_POST(gart_iommu_hole_init);
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index af3ba08b684b5..7a5630d904b23 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -392,7 +392,7 @@ void __init early_gart_iommu_check(void)
 
 static int __initdata printed_gart_size_msg;
 
-int __init gart_iommu_hole_init(void)
+void __init gart_iommu_hole_init(void)
 {
 	u32 agp_aper_base = 0, agp_aper_order = 0;
 	u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
@@ -401,11 +401,11 @@ int __init gart_iommu_hole_init(void)
 	int i, node;
 
 	if (!amd_gart_present())
-		return -ENODEV;
+		return;
 
 	if (gart_iommu_aperture_disabled || !fix_aperture ||
 	    !early_pci_allowed())
-		return -ENODEV;
+		return;
 
 	pr_info("Checking aperture...\n");
 
@@ -491,10 +491,8 @@ int __init gart_iommu_hole_init(void)
 			 * and fixed up the northbridge
 			 */
 			exclude_from_core(last_aper_base, last_aper_order);
-
-			return 1;
 		}
-		return 0;
+		return;
 	}
 
 	if (!fallback_aper_force) {
@@ -527,7 +525,7 @@ int __init gart_iommu_hole_init(void)
 			panic("Not enough memory for aperture");
 		}
 	} else {
-		return 0;
+		return;
 	}
 
 	/*
@@ -561,6 +559,4 @@ int __init gart_iommu_hole_init(void)
 	}
 
 	set_up_gart_resume(aper_order, aper_alloc);
-
-	return 1;
 }
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index de234e7a8962e..32c9cd9d7c257 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -7,13 +7,16 @@
 #include <linux/memblock.h>
 #include <linux/gfp.h>
 #include <linux/pci.h>
+#include <linux/amd-iommu.h>
 
 #include <asm/proto.h>
 #include <asm/dma.h>
 #include <asm/iommu.h>
 #include <asm/gart.h>
 #include <asm/x86_init.h>
-#include <asm/iommu_table.h>
+
+#include <xen/xen.h>
+#include <xen/swiotlb-xen.h>
 
 static bool disable_dac_quirk __read_mostly;
 
@@ -34,24 +37,63 @@ int no_iommu __read_mostly;
 /* Set this to 1 if there is a HW IOMMU in the system */
 int iommu_detected __read_mostly = 0;
 
-extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
+#ifdef CONFIG_SWIOTLB
+bool x86_swiotlb_enable;
+static bool xen_swiotlb;
 
-void __init pci_iommu_alloc(void)
+/*
+ * If 4GB or more detected (and iommu=off not set) or if SME is active
+ * then set swiotlb to 1 and return 1.
+ */
+static void __init pci_swiotlb_detect_4gb(void)
 {
-	struct iommu_table_entry *p;
-
-	sort_iommu_table(__iommu_table, __iommu_table_end);
-	check_iommu_entries(__iommu_table, __iommu_table_end);
-
-	for (p = __iommu_table; p < __iommu_table_end; p++) {
-		if (p && p->detect && p->detect() > 0) {
-			p->flags |= IOMMU_DETECTED;
-			if (p->early_init)
-				p->early_init();
-			if (p->flags & IOMMU_FINISH_IF_DETECTED)
-				break;
+#ifdef CONFIG_SWIOTLB_XEN
+	if (xen_pv_domain()) {
+		if (xen_initial_domain() || x86_swiotlb_enable ||
+		    swiotlb_force == SWIOTLB_FORCE) {
+			xen_swiotlb = true;
+			xen_swiotlb_init_early();
+			dma_ops = &xen_swiotlb_dma_ops;
+
+#ifdef CONFIG_PCI
+			/* Make sure ACS will be enabled */
+			pci_request_acs();
+#endif
 		}
+		x86_swiotlb_enable = false;
+		return;
 	}
+#endif /* CONFIG_SWIOTLB_XEN */
+
+	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
+	if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
+		x86_swiotlb_enable = true;
+
+	/*
+	 * Set swiotlb to 1 so that bounce buffers are allocated and used for
+	 * devices that can't support DMA to encrypted memory.
+	 */
+	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
+		x86_swiotlb_enable = true;
+
+	if (swiotlb_force == SWIOTLB_FORCE)
+		x86_swiotlb_enable = true;
+}
+#else
+static inline void __init pci_swiotlb_detect_4gb(void)
+{
+}
+#endif /* CONFIG_SWIOTLB */
+
+void __init pci_iommu_alloc(void)
+{
+	pci_swiotlb_detect_4gb();
+	gart_iommu_hole_init();
+	amd_iommu_detect();
+	detect_intel_iommu();
+
+	if (x86_swiotlb_enable)
+		swiotlb_init(0);
 }
 
 /*
@@ -102,7 +144,7 @@ static __init int iommu_setup(char *p)
 		}
 #ifdef CONFIG_SWIOTLB
 		if (!strncmp(p, "soft", 4))
-			swiotlb = 1;
+			x86_swiotlb_enable = 1;
 #endif
 		if (!strncmp(p, "pt", 2))
 			iommu_set_default_passthrough(true);
@@ -121,14 +163,18 @@ early_param("iommu", iommu_setup);
 
 static int __init pci_iommu_init(void)
 {
-	struct iommu_table_entry *p;
-
 	x86_init.iommu.iommu_init();
 
-	for (p = __iommu_table; p < __iommu_table_end; p++) {
-		if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
-			p->late_init();
+#ifdef CONFIG_SWIOTLB
+	/* An IOMMU turned us off. */
+	if (x86_swiotlb_enable) {
+		printk(KERN_INFO "PCI-DMA: "
+		       "Using software bounce buffering for IO (SWIOTLB)\n");
+		swiotlb_print_info();
+	} else {
+		swiotlb_exit();
 	}
+#endif
 
 	return 0;
 }
@@ -154,3 +200,27 @@ static void via_no_dac(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
 				PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
 #endif
+
+#ifdef CONFIG_SWIOTLB_XEN
+int pci_xen_swiotlb_init_late(void)
+{
+	int rc;
+
+	if (xen_swiotlb)
+		return 0;
+
+	rc = xen_swiotlb_init();
+	if (rc)
+		return rc;
+
+	/* XXX: this switches the dma ops under live devices! */
+	dma_ops = &xen_swiotlb_dma_ops;
+#ifdef CONFIG_PCI
+	/* Make sure ACS will be enabled */
+	pci_request_acs();
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
+#endif /* CONFIG_SWIOTLB_XEN */
diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c
deleted file mode 100644
index 42e92ec62973b..0000000000000
--- a/arch/x86/kernel/pci-iommu_table.c
+++ /dev/null
@@ -1,77 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/dma-mapping.h>
-#include <asm/iommu_table.h>
-#include <linux/string.h>
-#include <linux/kallsyms.h>
-
-static struct iommu_table_entry * __init
-find_dependents_of(struct iommu_table_entry *start,
-		   struct iommu_table_entry *finish,
-		   struct iommu_table_entry *q)
-{
-	struct iommu_table_entry *p;
-
-	if (!q)
-		return NULL;
-
-	for (p = start; p < finish; p++)
-		if (p->detect == q->depend)
-			return p;
-
-	return NULL;
-}
-
-
-void __init sort_iommu_table(struct iommu_table_entry *start,
-			     struct iommu_table_entry *finish) {
-
-	struct iommu_table_entry *p, *q, tmp;
-
-	for (p = start; p < finish; p++) {
-again:
-		q = find_dependents_of(start, finish, p);
-		/* We are bit sneaky here. We use the memory address to figure
-		 * out if the node we depend on is past our point, if so, swap.
-		 */
-		if (q > p) {
-			tmp = *p;
-			memmove(p, q, sizeof(*p));
-			*q = tmp;
-			goto again;
-		}
-	}
-
-}
-
-#ifdef DEBUG
-void __init check_iommu_entries(struct iommu_table_entry *start,
-				struct iommu_table_entry *finish)
-{
-	struct iommu_table_entry *p, *q, *x;
-
-	/* Simple cyclic dependency checker. */
-	for (p = start; p < finish; p++) {
-		q = find_dependents_of(start, finish, p);
-		x = find_dependents_of(start, finish, q);
-		if (p == x) {
-			printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
-			       p->detect, q->detect);
-			/* Heavy handed way..*/
-			x->depend = NULL;
-		}
-	}
-
-	for (p = start; p < finish; p++) {
-		q = find_dependents_of(p, finish, p);
-		if (q && q > p) {
-			printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
-			       p->detect, q->detect);
-		}
-	}
-}
-#else
-void __init check_iommu_entries(struct iommu_table_entry *start,
-				       struct iommu_table_entry *finish)
-{
-}
-#endif
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
deleted file mode 100644
index 814ab46a0dada..0000000000000
--- a/arch/x86/kernel/pci-swiotlb.c
+++ /dev/null
@@ -1,77 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <linux/pci.h>
-#include <linux/cache.h>
-#include <linux/init.h>
-#include <linux/swiotlb.h>
-#include <linux/memblock.h>
-#include <linux/dma-direct.h>
-#include <linux/cc_platform.h>
-
-#include <asm/iommu.h>
-#include <asm/swiotlb.h>
-#include <asm/dma.h>
-#include <asm/xen/swiotlb-xen.h>
-#include <asm/iommu_table.h>
-
-int swiotlb __read_mostly;
-
-/*
- * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
- *
- * This returns non-zero if we are forced to use swiotlb (by the boot
- * option).
- */
-int __init pci_swiotlb_detect_override(void)
-{
-	if (swiotlb_force == SWIOTLB_FORCE)
-		swiotlb = 1;
-
-	return swiotlb;
-}
-IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
-		  pci_xen_swiotlb_detect,
-		  pci_swiotlb_init,
-		  pci_swiotlb_late_init);
-
-/*
- * If 4GB or more detected (and iommu=off not set) or if SME is active
- * then set swiotlb to 1 and return 1.
- */
-int __init pci_swiotlb_detect_4gb(void)
-{
-	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
-	if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
-		swiotlb = 1;
-
-	/*
-	 * Set swiotlb to 1 so that bounce buffers are allocated and used for
-	 * devices that can't support DMA to encrypted memory.
-	 */
-	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
-		swiotlb = 1;
-
-	return swiotlb;
-}
-IOMMU_INIT(pci_swiotlb_detect_4gb,
-	   pci_swiotlb_detect_override,
-	   pci_swiotlb_init,
-	   pci_swiotlb_late_init);
-
-void __init pci_swiotlb_init(void)
-{
-	if (swiotlb)
-		swiotlb_init(0);
-}
-
-void __init pci_swiotlb_late_init(void)
-{
-	/* An IOMMU turned us off. */
-	if (!swiotlb)
-		swiotlb_exit();
-	else {
-		printk(KERN_INFO "PCI-DMA: "
-		       "Using software bounce buffering for IO (SWIOTLB)\n");
-		swiotlb_print_info();
-	}
-}
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index f9af561c3cd4f..0c1154a1c4032 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -24,7 +24,6 @@
 #include <asm/processor.h>
 #include <asm/bootparam.h>
 #include <asm/pgalloc.h>
-#include <asm/swiotlb.h>
 #include <asm/fixmap.h>
 #include <asm/proto.h>
 #include <asm/setup.h>
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 27f830345b6f0..bbe910c15b293 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -306,18 +306,6 @@ SECTIONS
 		*(.altinstr_replacement)
 	}
 
-	/*
-	 * struct iommu_table_entry entries are injected in this section.
-	 * It is an array of IOMMUs which during run time gets sorted depending
-	 * on its dependency order. After rootfs_initcall is complete
-	 * this section can be safely removed.
-	 */
-	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
-		__iommu_table = .;
-		*(.iommu_table)
-		__iommu_table_end = .;
-	}
-
 	. = ALIGN(8);
 	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
 		__apicdrivers = .;
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 4953260e281c3..3c5b52fbe4a7f 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -47,6 +47,4 @@ obj-$(CONFIG_XEN_DEBUG_FS)	+= debugfs.o
 
 obj-$(CONFIG_XEN_PV_DOM0)	+= vga.o
 
-obj-$(CONFIG_SWIOTLB_XEN)	+= pci-swiotlb-xen.o
-
 obj-$(CONFIG_XEN_EFI)		+= efi.o
diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
deleted file mode 100644
index 46df59aeaa06a..0000000000000
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ /dev/null
@@ -1,96 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-/* Glue code to lib/swiotlb-xen.c */
-
-#include <linux/dma-map-ops.h>
-#include <linux/pci.h>
-#include <xen/swiotlb-xen.h>
-
-#include <asm/xen/hypervisor.h>
-#include <xen/xen.h>
-#include <asm/iommu_table.h>
-
-
-#include <asm/xen/swiotlb-xen.h>
-#ifdef CONFIG_X86_64
-#include <asm/iommu.h>
-#include <asm/dma.h>
-#endif
-#include <linux/export.h>
-
-static int xen_swiotlb __read_mostly;
-
-/*
- * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
- *
- * This returns non-zero if we are forced to use xen_swiotlb (by the boot
- * option).
- */
-int __init pci_xen_swiotlb_detect(void)
-{
-
-	if (!xen_pv_domain())
-		return 0;
-
-	/* If running as PV guest, either iommu=soft, or swiotlb=force will
-	 * activate this IOMMU. If running as PV privileged, activate it
-	 * irregardless.
-	 */
-	if (xen_initial_domain() || swiotlb || swiotlb_force == SWIOTLB_FORCE)
-		xen_swiotlb = 1;
-
-	/* If we are running under Xen, we MUST disable the native SWIOTLB.
-	 * Don't worry about swiotlb_force flag activating the native, as
-	 * the 'swiotlb' flag is the only one turning it on. */
-	swiotlb = 0;
-
-#ifdef CONFIG_X86_64
-	/* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu == 0
-	 * (so no iommu=X command line over-writes).
-	 * Considering that PV guests do not want the *native SWIOTLB* but
-	 * only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
-	 */
-	if (max_pfn > MAX_DMA32_PFN)
-		no_iommu = 1;
-#endif
-	return xen_swiotlb;
-}
-
-static void __init pci_xen_swiotlb_init(void)
-{
-	if (xen_swiotlb) {
-		xen_swiotlb_init_early();
-		dma_ops = &xen_swiotlb_dma_ops;
-
-#ifdef CONFIG_PCI
-		/* Make sure ACS will be enabled */
-		pci_request_acs();
-#endif
-	}
-}
-
-int pci_xen_swiotlb_init_late(void)
-{
-	int rc;
-
-	if (xen_swiotlb)
-		return 0;
-
-	rc = xen_swiotlb_init();
-	if (rc)
-		return rc;
-
-	dma_ops = &xen_swiotlb_dma_ops;
-#ifdef CONFIG_PCI
-	/* Make sure ACS will be enabled */
-	pci_request_acs();
-#endif
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
-
-IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
-		  NULL,
-		  pci_xen_swiotlb_init,
-		  NULL);
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index b10fb52ea4428..721300cf90207 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -27,7 +27,6 @@
 #include <asm/apic.h>
 #include <asm/gart.h>
 #include <asm/x86_init.h>
-#include <asm/iommu_table.h>
 #include <asm/io_apic.h>
 #include <asm/irq_remapping.h>
 #include <asm/set_memory.h>
@@ -3237,11 +3236,6 @@ __setup("ivrs_ioapic",		parse_ivrs_ioapic);
 __setup("ivrs_hpet",		parse_ivrs_hpet);
 __setup("ivrs_acpihid",		parse_ivrs_acpihid);
 
-IOMMU_INIT_FINISH(amd_iommu_detect,
-		  gart_iommu_hole_init,
-		  NULL,
-		  NULL);
-
 bool amd_iommu_v2_supported(void)
 {
 	return amd_iommu_v2_present;
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 461f1844ed1fb..4f9672b18ad1a 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1834,7 +1834,10 @@ void amd_iommu_domain_update(struct protection_domain *domain)
 
 static void __init amd_iommu_init_dma_ops(void)
 {
-	swiotlb = (iommu_default_passthrough() || sme_me_mask) ? 1 : 0;
+	if (iommu_default_passthrough() || sme_me_mask) 
+		x86_swiotlb_enable = true;
+	else
+		x86_swiotlb_enable = false;
 }
 
 int __init amd_iommu_init_api(void)
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 915bff76fe965..29bee4b210c5b 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -30,7 +30,6 @@
 #include <linux/numa.h>
 #include <linux/limits.h>
 #include <asm/irq_remapping.h>
-#include <asm/iommu_table.h>
 #include <trace/events/intel_iommu.h>
 
 #include "../irq_remapping.h"
@@ -913,7 +912,7 @@ dmar_validate_one_drhd(struct acpi_dmar_header *entry, void *arg)
 	return 0;
 }
 
-int __init detect_intel_iommu(void)
+void __init detect_intel_iommu(void)
 {
 	int ret;
 	struct dmar_res_callback validate_drhd_cb = {
@@ -946,8 +945,6 @@ int __init detect_intel_iommu(void)
 		dmar_tbl = NULL;
 	}
 	up_write(&dmar_global_lock);
-
-	return ret ? ret : 1;
 }
 
 static void unmap_iommu(struct intel_iommu *iommu)
@@ -2165,7 +2162,6 @@ static int __init dmar_free_unused_resources(void)
 }
 
 late_initcall(dmar_free_unused_resources);
-IOMMU_INIT_POST(detect_intel_iommu);
 
 /*
  * DMAR Hotplug Support
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 45e903d847335..cbd714a198a0a 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -121,7 +121,7 @@ extern int dmar_remove_dev_scope(struct dmar_pci_notify_info *info,
 				 u16 segment, struct dmar_dev_scope *devices,
 				 int count);
 /* Intel IOMMU detection */
-extern int detect_intel_iommu(void);
+void detect_intel_iommu(void);
 extern int enable_drhd_fault_handling(void);
 extern int dmar_device_add(acpi_handle handle);
 extern int dmar_device_remove(acpi_handle handle);
@@ -197,6 +197,10 @@ static inline bool dmar_platform_optin(void)
 	return false;
 }
 
+static inline void detect_intel_iommu(void)
+{
+}
+
 #endif /* CONFIG_DMAR_TABLE */
 
 struct irte {
-- 
2.30.2

Re: [PATCH 07/11] x86: remove the IOMMU table infrastructure

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> The IOMMU table tries to separate the different IOMMUs into different
> backends, but actually requires various cross calls.
> 
> Rewrite the code to do the generic swiotlb/swiotlb-xen setup directly
> in pci-dma.c and then just call into the IOMMU drivers.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/ia64/include/asm/iommu_table.h    |   7 --
>  arch/x86/include/asm/dma-mapping.h     |   1 -
>  arch/x86/include/asm/gart.h            |   5 +-
>  arch/x86/include/asm/iommu.h           |   6 ++
>  arch/x86/include/asm/iommu_table.h     | 102 ----------------------
>  arch/x86/include/asm/swiotlb.h         |  30 -------
>  arch/x86/include/asm/xen/swiotlb-xen.h |   2 -
>  arch/x86/kernel/Makefile               |   2 -
>  arch/x86/kernel/amd_gart_64.c          |   5 +-
>  arch/x86/kernel/aperture_64.c          |  14 ++--
>  arch/x86/kernel/pci-dma.c              | 112 ++++++++++++++++++++-----
>  arch/x86/kernel/pci-iommu_table.c      |  77 -----------------
>  arch/x86/kernel/pci-swiotlb.c          |  77 -----------------
>  arch/x86/kernel/tboot.c                |   1 -
>  arch/x86/kernel/vmlinux.lds.S          |  12 ---
>  arch/x86/xen/Makefile                  |   2 -
>  arch/x86/xen/pci-swiotlb-xen.c         |  96 ---------------------
>  drivers/iommu/amd/init.c               |   6 --
>  drivers/iommu/amd/iommu.c              |   5 +-
>  drivers/iommu/intel/dmar.c             |   6 +-
>  include/linux/dmar.h                   |   6 +-
>  21 files changed, 115 insertions(+), 459 deletions(-)
>  delete mode 100644 arch/ia64/include/asm/iommu_table.h
>  delete mode 100644 arch/x86/include/asm/iommu_table.h
>  delete mode 100644 arch/x86/include/asm/swiotlb.h
>  delete mode 100644 arch/x86/kernel/pci-iommu_table.c
>  delete mode 100644 arch/x86/kernel/pci-swiotlb.c
>  delete mode 100644 arch/x86/xen/pci-swiotlb-xen.c

checkpatch.pl has some warnings here.

WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#44: 
deleted file mode 100644

WARNING: Prefer [subsystem eg: netdev]_info([subsystem]dev, ... then dev_info(dev, ... then pr_info(...  to printk(KERN_INFO ...
#496: FILE: arch/x86/kernel/pci-dma.c:171:
+               printk(KERN_INFO "PCI-DMA: "

WARNING: quoted string split across lines
#497: FILE: arch/x86/kernel/pci-dma.c:172:
+               printk(KERN_INFO "PCI-DMA: "
+                      "Using software bounce buffering for IO (SWIOTLB)\n");

ERROR: trailing whitespace
#881: FILE: drivers/iommu/amd/iommu.c:1837:
+^Iif (iommu_default_passthrough() || sme_me_mask) $

total: 1 errors, 3 warnings, 389 lines checked

[PATCH 08/11] swiotlb: make the swiotlb_init interface more useful

[Christoph Hellwig]

Pass a bool to pass if swiotlb needs to be enabled based on the
addressing needs and replace the verbose argument with a set of
flags, including one to force enable bounce buffering.

Note that this patch removes the possibility to force xen-swiotlb
use using swiotlb=force on the command line on x86 (arm and arm64
never supported that), but this interface will be restored shortly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arm/mm/init.c                     |  6 +----
 arch/arm64/mm/init.c                   |  6 +----
 arch/ia64/mm/init.c                    |  4 +--
 arch/mips/cavium-octeon/dma-octeon.c   |  2 +-
 arch/mips/loongson64/dma.c             |  2 +-
 arch/mips/sibyte/common/dma.c          |  2 +-
 arch/powerpc/include/asm/swiotlb.h     |  1 +
 arch/powerpc/mm/mem.c                  |  3 ++-
 arch/powerpc/platforms/pseries/setup.c |  3 ---
 arch/riscv/mm/init.c                   |  8 +-----
 arch/s390/mm/init.c                    |  3 +--
 arch/x86/kernel/cpu/mshyperv.c         |  8 ------
 arch/x86/kernel/pci-dma.c              | 17 ++++++-------
 arch/x86/mm/mem_encrypt_amd.c          |  3 ---
 drivers/xen/swiotlb-xen.c              |  4 +--
 include/linux/swiotlb.h                | 15 ++++++-----
 include/trace/events/swiotlb.h         | 29 ++++++++-------------
 kernel/dma/swiotlb.c                   | 35 ++++++++++++++------------
 18 files changed, 57 insertions(+), 94 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 6d0cb0f7bc54b..73f30d278b565 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -312,11 +312,7 @@ static void __init free_highpages(void)
 void __init mem_init(void)
 {
 #ifdef CONFIG_ARM_LPAE
-	if (swiotlb_force == SWIOTLB_FORCE ||
-	    max_pfn > arm_dma_pfn_limit)
-		swiotlb_init(1);
-	else
-		swiotlb_force = SWIOTLB_NO_FORCE;
+	swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
 #endif
 
 	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index db63cc885771a..52102adda3d28 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -373,11 +373,7 @@ void __init bootmem_init(void)
  */
 void __init mem_init(void)
 {
-	if (swiotlb_force == SWIOTLB_FORCE ||
-	    max_pfn > PFN_DOWN(arm64_dma_phys_limit))
-		swiotlb_init(1);
-	else if (!xen_swiotlb_detect())
-		swiotlb_force = SWIOTLB_NO_FORCE;
+	swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE);
 
 	/* this will put all unused low memory onto the freelists */
 	memblock_free_all();
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 5d165607bf354..3c3e15b22608f 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -437,9 +437,7 @@ mem_init (void)
 		if (iommu_detected)
 			break;
 #endif
-#ifdef CONFIG_SWIOTLB
-		swiotlb_init(1);
-#endif
+		swiotlb_init(true, SWIOTLB_VERBOSE);
 	} while (0);
 
 #ifdef CONFIG_FLATMEM
diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
index fb7547e217263..9fbba6a8fa4c5 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -235,5 +235,5 @@ void __init plat_swiotlb_setup(void)
 #endif
 
 	swiotlb_adjust_size(swiotlbsize);
-	swiotlb_init(1);
+	swiotlb_init(true, SWIOTLB_VERBOSE);
 }
diff --git a/arch/mips/loongson64/dma.c b/arch/mips/loongson64/dma.c
index 364f2f27c8723..8220a1bc0db64 100644
--- a/arch/mips/loongson64/dma.c
+++ b/arch/mips/loongson64/dma.c
@@ -24,5 +24,5 @@ phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
 
 void __init plat_swiotlb_setup(void)
 {
-	swiotlb_init(1);
+	swiotlb_init(true, SWIOTLB_VERBOSE);
 }
diff --git a/arch/mips/sibyte/common/dma.c b/arch/mips/sibyte/common/dma.c
index eb47a94f3583e..c5c2c782aff68 100644
--- a/arch/mips/sibyte/common/dma.c
+++ b/arch/mips/sibyte/common/dma.c
@@ -10,5 +10,5 @@
 
 void __init plat_swiotlb_setup(void)
 {
-	swiotlb_init(1);
+	swiotlb_init(true, SWIOTLB_VERBOSE);
 }
diff --git a/arch/powerpc/include/asm/swiotlb.h b/arch/powerpc/include/asm/swiotlb.h
index 3c1a1cd161286..4203b5e0a88ed 100644
--- a/arch/powerpc/include/asm/swiotlb.h
+++ b/arch/powerpc/include/asm/swiotlb.h
@@ -9,6 +9,7 @@
 #include <linux/swiotlb.h>
 
 extern unsigned int ppc_swiotlb_enable;
+extern unsigned int ppc_swiotlb_flags;
 
 #ifdef CONFIG_SWIOTLB
 void swiotlb_detect_4g(void);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8e301cd8925b2..d99b8b5b40ca6 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -17,6 +17,7 @@
 #include <linux/suspend.h>
 #include <linux/dma-direct.h>
 
+#include <asm/swiotlb.h>
 #include <asm/machdep.h>
 #include <asm/rtas.h>
 #include <asm/kasan.h>
@@ -251,7 +252,7 @@ void __init mem_init(void)
 	if (is_secure_guest())
 		svm_swiotlb_init();
 	else
-		swiotlb_init(0);
+		swiotlb_init(ppc_swiotlb_enable, ppc_swiotlb_flags);
 #endif
 
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 83a04d967a59f..45d637ab58261 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -838,9 +838,6 @@ static void __init pSeries_setup_arch(void)
 	}
 
 	ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
-
-	if (swiotlb_force == SWIOTLB_FORCE)
-		ppc_swiotlb_enable = 1;
 }
 
 static void pseries_panic(char *str)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index c27294128e182..6cdbb62672fe5 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -118,13 +118,7 @@ void __init mem_init(void)
 	BUG_ON(!mem_map);
 #endif /* CONFIG_FLATMEM */
 
-#ifdef CONFIG_SWIOTLB
-	if (swiotlb_force == SWIOTLB_FORCE ||
-	    max_pfn > PFN_DOWN(dma32_phys_limit))
-		swiotlb_init(1);
-	else
-		swiotlb_force = SWIOTLB_NO_FORCE;
-#endif
+	swiotlb_init(max_pfn > PFN_DOWN(dma32_phys_limit), SWIOTLB_VERBOSE);
 	high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
 	memblock_free_all();
 
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 86ffd0d51fd59..6fb6bf64326f9 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -185,8 +185,7 @@ static void pv_init(void)
 		return;
 
 	/* make sure bounce buffers are shared */
-	swiotlb_force = SWIOTLB_FORCE;
-	swiotlb_init(1);
+	swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE);
 	swiotlb_update_mem_attributes();
 }
 
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 5a99f993e6392..568274917f1cd 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -336,14 +336,6 @@ static void __init ms_hyperv_init_platform(void)
 			swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
 #endif
 		}
-
-#ifdef CONFIG_SWIOTLB
-		/*
-		 * Enable swiotlb force mode in Isolation VM to
-		 * use swiotlb bounce buffer for dma transaction.
-		 */
-		swiotlb_force = SWIOTLB_FORCE;
-#endif
 	}
 
 	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 32c9cd9d7c257..9576a02a2590f 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -39,6 +39,7 @@ int iommu_detected __read_mostly = 0;
 
 #ifdef CONFIG_SWIOTLB
 bool x86_swiotlb_enable;
+static unsigned int x86_swiotlb_flags;
 static bool xen_swiotlb;
 
 /*
@@ -49,8 +50,7 @@ static void __init pci_swiotlb_detect_4gb(void)
 {
 #ifdef CONFIG_SWIOTLB_XEN
 	if (xen_pv_domain()) {
-		if (xen_initial_domain() || x86_swiotlb_enable ||
-		    swiotlb_force == SWIOTLB_FORCE) {
+		if (xen_initial_domain() || x86_swiotlb_enable) {
 			xen_swiotlb = true;
 			xen_swiotlb_init_early();
 			dma_ops = &xen_swiotlb_dma_ops;
@@ -73,11 +73,10 @@ static void __init pci_swiotlb_detect_4gb(void)
 	 * Set swiotlb to 1 so that bounce buffers are allocated and used for
 	 * devices that can't support DMA to encrypted memory.
 	 */
-	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
-		x86_swiotlb_enable = true;
-
-	if (swiotlb_force == SWIOTLB_FORCE)
+	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
 		x86_swiotlb_enable = true;
+		x86_swiotlb_flags |= SWIOTLB_FORCE;
+	}
 }
 #else
 static inline void __init pci_swiotlb_detect_4gb(void)
@@ -91,9 +90,9 @@ void __init pci_iommu_alloc(void)
 	gart_iommu_hole_init();
 	amd_iommu_detect();
 	detect_intel_iommu();
-
-	if (x86_swiotlb_enable)
-		swiotlb_init(0);
+#ifdef CONFIG_SWIOTLB
+	swiotlb_init(x86_swiotlb_enable, x86_swiotlb_flags);
+#endif
 }
 
 /*
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 2b2d018ea3450..a72942d569cf9 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -191,9 +191,6 @@ void __init sme_early_init(void)
 	/* Update the protection map with memory encryption mask */
 	for (i = 0; i < ARRAY_SIZE(protection_map); i++)
 		protection_map[i] = pgprot_encrypted(protection_map[i]);
-
-	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
-		swiotlb_force = SWIOTLB_FORCE;
 }
 
 void __init sev_setup_arch(void)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 485cd06ed39e7..c2da3eb4826e8 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -251,7 +251,7 @@ void __init xen_swiotlb_init_early(void)
 		panic("%s (rc:%d)", xen_swiotlb_error(XEN_SWIOTLB_EFIXUP), rc);
 	}
 
-	if (swiotlb_init_with_tbl(start, nslabs, true))
+	if (swiotlb_init_with_tbl(start, nslabs, SWIOTLB_VERBOSE))
 		panic("Cannot allocate SWIOTLB buffer");
 }
 #endif /* CONFIG_X86 */
@@ -376,7 +376,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 	/*
 	 * Oh well, have to allocate and map a bounce buffer.
 	 */
-	trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
+	trace_swiotlb_bounced(dev, dev_addr, size);
 
 	map = swiotlb_tbl_map_single(dev, phys, size, size, 0, dir, attrs);
 	if (map == (phys_addr_t)DMA_MAPPING_ERROR)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 1befd6b2ccf5e..dcecf953f7997 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -13,11 +13,8 @@ struct device;
 struct page;
 struct scatterlist;
 
-enum swiotlb_force {
-	SWIOTLB_NORMAL,		/* Default - depending on HW DMA mask etc. */
-	SWIOTLB_FORCE,		/* swiotlb=force */
-	SWIOTLB_NO_FORCE,	/* swiotlb=noforce */
-};
+#define SWIOTLB_VERBOSE	(1 << 0) /* verbose initialization */
+#define SWIOTLB_FORCE	(1 << 1) /* force bounce buffering */
 
 /*
  * Maximum allowable number of contiguous slabs to map,
@@ -36,8 +33,7 @@ enum swiotlb_force {
 /* default to 64MB */
 #define IO_TLB_DEFAULT_SIZE (64UL<<20)
 
-extern void swiotlb_init(int verbose);
-int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
+int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags);
 unsigned long swiotlb_size_or_default(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
 int swiotlb_init_late(size_t size, gfp_t gfp_mask);
@@ -126,13 +122,16 @@ static inline bool is_swiotlb_force_bounce(struct device *dev)
 	return mem && mem->force_bounce;
 }
 
+void swiotlb_init(bool addressing_limited, unsigned int flags);
 void __init swiotlb_exit(void);
 unsigned int swiotlb_max_segment(void);
 size_t swiotlb_max_mapping_size(struct device *dev);
 bool is_swiotlb_active(struct device *dev);
 void __init swiotlb_adjust_size(unsigned long size);
 #else
-#define swiotlb_force SWIOTLB_NO_FORCE
+static inline void swiotlb_init(bool addressing_limited, unsigned int flags)
+{
+}
 static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
 	return false;
diff --git a/include/trace/events/swiotlb.h b/include/trace/events/swiotlb.h
index 705be43b71ab0..da05c9ebd224a 100644
--- a/include/trace/events/swiotlb.h
+++ b/include/trace/events/swiotlb.h
@@ -8,20 +8,15 @@
 #include <linux/tracepoint.h>
 
 TRACE_EVENT(swiotlb_bounced,
-
-	TP_PROTO(struct device *dev,
-		 dma_addr_t dev_addr,
-		 size_t size,
-		 enum swiotlb_force swiotlb_force),
-
-	TP_ARGS(dev, dev_addr, size, swiotlb_force),
+	TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
+	TP_ARGS(dev, dev_addr, size),
 
 	TP_STRUCT__entry(
-		__string(	dev_name,	dev_name(dev)		)
-		__field(	u64,	dma_mask			)
-		__field(	dma_addr_t,	dev_addr		)
-		__field(	size_t,	size				)
-		__field(	enum swiotlb_force,	swiotlb_force	)
+		__string(dev_name, dev_name(dev))
+		__field(u64, dma_mask)
+		__field(dma_addr_t, dev_addr)
+		__field(size_t, size)
+		__field(bool, force)
 	),
 
 	TP_fast_assign(
@@ -29,19 +24,15 @@ TRACE_EVENT(swiotlb_bounced,
 		__entry->dma_mask = (dev->dma_mask ? *dev->dma_mask : 0);
 		__entry->dev_addr = dev_addr;
 		__entry->size = size;
-		__entry->swiotlb_force = swiotlb_force;
+		__entry->force = is_swiotlb_force_bounce(dev);
 	),
 
-	TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx "
-		"size=%zu %s",
+	TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx size=%zu %s",
 		__get_str(dev_name),
 		__entry->dma_mask,
 		(unsigned long long)__entry->dev_addr,
 		__entry->size,
-		__print_symbolic(__entry->swiotlb_force,
-			{ SWIOTLB_NORMAL,	"NORMAL" },
-			{ SWIOTLB_FORCE,	"FORCE" },
-			{ SWIOTLB_NO_FORCE,	"NO_FORCE" }))
+		__entry->force ? "FORCE" : "NORMAL")
 );
 
 #endif /*  _TRACE_SWIOTLB_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index a653fcf1fe6c2..ad604e5a0983d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -69,7 +69,8 @@
 
 #define INVALID_PHYS_ADDR (~(phys_addr_t)0)
 
-enum swiotlb_force swiotlb_force;
+static bool swiotlb_force_bounce;
+static bool swiotlb_force_disable;
 
 struct io_tlb_mem io_tlb_default_mem;
 
@@ -88,9 +89,9 @@ setup_io_tlb_npages(char *str)
 	if (*str == ',')
 		++str;
 	if (!strcmp(str, "force"))
-		swiotlb_force = SWIOTLB_FORCE;
+		swiotlb_force_bounce = true;
 	else if (!strcmp(str, "noforce"))
-		swiotlb_force = SWIOTLB_NO_FORCE;
+		swiotlb_force_disable = true;
 
 	return 0;
 }
@@ -211,7 +212,7 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
 	mem->index = 0;
 	mem->late_alloc = late_alloc;
 
-	if (swiotlb_force == SWIOTLB_FORCE)
+	if (swiotlb_force_bounce)
 		mem->force_bounce = true;
 
 	spin_lock_init(&mem->lock);
@@ -233,12 +234,13 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
 	return;
 }
 
-int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
+int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs,
+		unsigned int flags)
 {
 	struct io_tlb_mem *mem = &io_tlb_default_mem;
 	size_t alloc_size;
 
-	if (swiotlb_force == SWIOTLB_NO_FORCE)
+	if (swiotlb_force_disable)
 		return 0;
 
 	/* protect against double initialization */
@@ -252,8 +254,9 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 		      __func__, alloc_size, PAGE_SIZE);
 
 	swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, false);
+	mem->force_bounce = flags & SWIOTLB_FORCE;
 
-	if (verbose)
+	if (flags & SWIOTLB_VERBOSE)
 		swiotlb_print_info();
 	return 0;
 }
@@ -262,20 +265,21 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
  * Statically reserve bounce buffer space and initialize bounce buffer data
  * structures for the software IO TLB used to implement the DMA API.
  */
-void  __init
-swiotlb_init(int verbose)
+void __init swiotlb_init(bool addressing_limit, unsigned int flags)
 {
 	size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT);
 	void *tlb;
 
-	if (swiotlb_force == SWIOTLB_NO_FORCE)
+	if (!addressing_limit && !swiotlb_force_bounce)
+		return;
+	if (swiotlb_force_disable)
 		return;
 
 	/* Get IO TLB memory from the low pages */
 	tlb = memblock_alloc_low(bytes, PAGE_SIZE);
 	if (!tlb)
 		goto fail;
-	if (swiotlb_init_with_tbl(tlb, default_nslabs, verbose))
+	if (swiotlb_init_with_tbl(tlb, default_nslabs, flags))
 		goto fail_free_mem;
 	return;
 
@@ -298,7 +302,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask)
 	unsigned int order;
 	int rc = 0;
 
-	if (swiotlb_force == SWIOTLB_NO_FORCE)
+	if (swiotlb_force_disable)
 		return 0;
 
 	/*
@@ -337,7 +341,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	struct io_tlb_mem *mem = &io_tlb_default_mem;
 	unsigned long bytes = nslabs << IO_TLB_SHIFT;
 
-	if (swiotlb_force == SWIOTLB_NO_FORCE)
+	if (swiotlb_force_disable)
 		return 0;
 
 	/* protect against double initialization */
@@ -362,7 +366,7 @@ void __init swiotlb_exit(void)
 	unsigned long tbl_vaddr;
 	size_t tbl_size, slots_size;
 
-	if (swiotlb_force == SWIOTLB_FORCE)
+	if (swiotlb_force_bounce)
 		return;
 
 	if (!mem->nslabs)
@@ -708,8 +712,7 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
 	phys_addr_t swiotlb_addr;
 	dma_addr_t dma_addr;
 
-	trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size,
-			      swiotlb_force);
+	trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size);
 
 	swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, 0, dir,
 			attrs);
-- 
2.30.2

[PATCH 09/11] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction

[Christoph Hellwig]

Power SVM wants to allocate a swiotlb buffer that is not restricted to
low memory for the trusted hypervisor scheme.  Consolidate the support
for this into the swiotlb_init interface by adding a new flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/powerpc/include/asm/svm.h       |  4 ----
 arch/powerpc/mm/mem.c                |  5 +----
 arch/powerpc/platforms/pseries/svm.c | 26 +-------------------------
 include/linux/swiotlb.h              |  1 +
 kernel/dma/swiotlb.c                 |  9 +++++++--
 5 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/arch/powerpc/include/asm/svm.h b/arch/powerpc/include/asm/svm.h
index 7546402d796af..85580b30aba48 100644
--- a/arch/powerpc/include/asm/svm.h
+++ b/arch/powerpc/include/asm/svm.h
@@ -15,8 +15,6 @@ static inline bool is_secure_guest(void)
 	return mfmsr() & MSR_S;
 }
 
-void __init svm_swiotlb_init(void);
-
 void dtl_cache_ctor(void *addr);
 #define get_dtl_cache_ctor()	(is_secure_guest() ? dtl_cache_ctor : NULL)
 
@@ -27,8 +25,6 @@ static inline bool is_secure_guest(void)
 	return false;
 }
 
-static inline void svm_swiotlb_init(void) {}
-
 #define get_dtl_cache_ctor() NULL
 
 #endif /* CONFIG_PPC_SVM */
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index d99b8b5b40ca6..a4d65418c30a9 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -249,10 +249,7 @@ void __init mem_init(void)
 	 * back to to-down.
 	 */
 	memblock_set_bottom_up(true);
-	if (is_secure_guest())
-		svm_swiotlb_init();
-	else
-		swiotlb_init(ppc_swiotlb_enable, ppc_swiotlb_flags);
+	swiotlb_init(ppc_swiotlb_enable, ppc_swiotlb_flags);
 #endif
 
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index c5228f4969eb2..3b4045d508ec8 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -28,7 +28,7 @@ static int __init init_svm(void)
 	 * need to use the SWIOTLB buffer for DMA even if dma_capable() says
 	 * otherwise.
 	 */
-	swiotlb_force = SWIOTLB_FORCE;
+	ppc_swiotlb_flags |= SWIOTLB_ANY | SWIOTLB_FORCE;
 
 	/* Share the SWIOTLB buffer with the host. */
 	swiotlb_update_mem_attributes();
@@ -37,30 +37,6 @@ static int __init init_svm(void)
 }
 machine_early_initcall(pseries, init_svm);
 
-/*
- * Initialize SWIOTLB. Essentially the same as swiotlb_init(), except that it
- * can allocate the buffer anywhere in memory. Since the hypervisor doesn't have
- * any addressing limitation, we don't need to allocate it in low addresses.
- */
-void __init svm_swiotlb_init(void)
-{
-	unsigned char *vstart;
-	unsigned long bytes, io_tlb_nslabs;
-
-	io_tlb_nslabs = (swiotlb_size_or_default() >> IO_TLB_SHIFT);
-	io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
-
-	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
-
-	vstart = memblock_alloc(PAGE_ALIGN(bytes), PAGE_SIZE);
-	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, false))
-		return;
-
-
-	memblock_free(vstart, PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
-	panic("SVM: Cannot allocate SWIOTLB buffer");
-}
-
 int set_memory_encrypted(unsigned long addr, int numpages)
 {
 	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index dcecf953f7997..ee655f2e4d28b 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -15,6 +15,7 @@ struct scatterlist;
 
 #define SWIOTLB_VERBOSE	(1 << 0) /* verbose initialization */
 #define SWIOTLB_FORCE	(1 << 1) /* force bounce buffering */
+#define SWIOTLB_ANY	(1 << 2) /* allow any memory for the buffer */
 
 /*
  * Maximum allowable number of contiguous slabs to map,
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index ad604e5a0983d..ec200e40fc397 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -275,8 +275,13 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags)
 	if (swiotlb_force_disable)
 		return;
 
-	/* Get IO TLB memory from the low pages */
-	tlb = memblock_alloc_low(bytes, PAGE_SIZE);
+	/*
+	 * By default allocate the bonuce buffer memory from low memory.
+	 */
+	if (flags & SWIOTLB_ANY)
+		tlb = memblock_alloc(bytes, PAGE_SIZE);
+	else
+		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
 	if (!tlb)
 		goto fail;
 	if (swiotlb_init_with_tbl(tlb, default_nslabs, flags))
-- 
2.30.2

[PATCH 10/11] swiotlb: merge swiotlb-xen initialization into swiotlb

[Christoph Hellwig]

Allow to pass a remap argument to the swiotlb initialization functions
to handle the Xen/x86 remap case.  ARM/ARM64 never did any remapping
from xen_swiotlb_fixup, so we don't even need that quirk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arm/xen/mm.c               |  23 +++---
 arch/x86/include/asm/xen/page.h |   5 --
 arch/x86/kernel/pci-dma.c       |  27 ++++---
 arch/x86/pci/sta2x11-fixup.c    |   2 +-
 drivers/xen/swiotlb-xen.c       | 128 +-------------------------------
 include/linux/swiotlb.h         |   7 +-
 include/xen/arm/page.h          |   1 -
 include/xen/swiotlb-xen.h       |   8 +-
 kernel/dma/swiotlb.c            | 120 +++++++++++++++---------------
 9 files changed, 102 insertions(+), 219 deletions(-)

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index a7e54a087b802..58b40f87617d3 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -23,22 +23,20 @@
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
-unsigned long xen_get_swiotlb_free_pages(unsigned int order)
+static gfp_t xen_swiotlb_gfp(void)
 {
 	phys_addr_t base;
-	gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM;
 	u64 i;
 
 	for_each_mem_range(i, &base, NULL) {
 		if (base < (phys_addr_t)0xffffffff) {
 			if (IS_ENABLED(CONFIG_ZONE_DMA32))
-				flags |= __GFP_DMA32;
-			else
-				flags |= __GFP_DMA;
-			break;
+				return __GFP_DMA32;
+			return __GFP_DMA;
 		}
 	}
-	return __get_free_pages(flags, order);
+
+	return GFP_KERNEL;
 }
 
 static bool hypercall_cflush = false;
@@ -143,10 +141,15 @@ static int __init xen_mm_init(void)
 	if (!xen_swiotlb_detect())
 		return 0;
 
-	rc = xen_swiotlb_init();
 	/* we can work with the default swiotlb */
-	if (rc < 0 && rc != -EEXIST)
-		return rc;
+	if (!io_tlb_default_mem.nslabs) {
+		if (!xen_initial_domain())
+			return -EINVAL;
+		rc = swiotlb_init_late(swiotlb_size_or_default(),
+				       xen_swiotlb_gfp(), NULL);
+		if (rc < 0)
+			return rc;
+	}
 
 	cflush.op = 0;
 	cflush.a.dev_bus_addr = 0;
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index e989bc2269f54..1fc67df500145 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -357,9 +357,4 @@ static inline bool xen_arch_need_swiotlb(struct device *dev,
 	return false;
 }
 
-static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
-{
-	return __get_free_pages(__GFP_NOWARN, order);
-}
-
 #endif /* _ASM_X86_XEN_PAGE_H */
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 9576a02a2590f..b849f11a756d0 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -40,7 +40,6 @@ int iommu_detected __read_mostly = 0;
 #ifdef CONFIG_SWIOTLB
 bool x86_swiotlb_enable;
 static unsigned int x86_swiotlb_flags;
-static bool xen_swiotlb;
 
 /*
  * If 4GB or more detected (and iommu=off not set) or if SME is active
@@ -50,17 +49,16 @@ static void __init pci_swiotlb_detect_4gb(void)
 {
 #ifdef CONFIG_SWIOTLB_XEN
 	if (xen_pv_domain()) {
-		if (xen_initial_domain() || x86_swiotlb_enable) {
-			xen_swiotlb = true;
-			xen_swiotlb_init_early();
-			dma_ops = &xen_swiotlb_dma_ops;
+		if (xen_initial_domain())
+			x86_swiotlb_enable = true;
 
+		if (x86_swiotlb_enable) {
+			dma_ops = &xen_swiotlb_dma_ops;
 #ifdef CONFIG_PCI
 			/* Make sure ACS will be enabled */
 			pci_request_acs();
 #endif
 		}
-		x86_swiotlb_enable = false;
 		return;
 	}
 #endif /* CONFIG_SWIOTLB_XEN */
@@ -91,7 +89,8 @@ void __init pci_iommu_alloc(void)
 	amd_iommu_detect();
 	detect_intel_iommu();
 #ifdef CONFIG_SWIOTLB
-	swiotlb_init(x86_swiotlb_enable, x86_swiotlb_flags);
+	swiotlb_init_remap(x86_swiotlb_enable, x86_swiotlb_flags,
+			   xen_pv_domain() ? xen_swiotlb_fixup : NULL);
 #endif
 }
 
@@ -205,13 +204,17 @@ int pci_xen_swiotlb_init_late(void)
 {
 	int rc;
 
-	if (xen_swiotlb)
+	if (dma_ops == &xen_swiotlb_dma_ops)
 		return 0;
 
-	rc = xen_swiotlb_init();
-	if (rc)
-		return rc;
-
+	/* we can work with the default swiotlb */
+	if (!io_tlb_default_mem.nslabs) {
+		rc = swiotlb_init_late(swiotlb_size_or_default(),
+				       GFP_KERNEL, xen_swiotlb_fixup);
+		if (rc < 0)
+			return rc;
+	}
+ 
 	/* XXX: this switches the dma ops under live devices! */
 	dma_ops = &xen_swiotlb_dma_ops;
 #ifdef CONFIG_PCI
diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index c7e6faf59a861..7368afc039987 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev)
 		int size = STA2X11_SWIOTLB_SIZE;
 		/* First instance: register your own swiotlb area */
 		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
-		if (swiotlb_init_late(size, GFP_DMA))
+		if (swiotlb_init_late(size, GFP_DMA, NULL))
 			dev_emerg(&pdev->dev, "init swiotlb failed\n");
 	}
 	list_add(&instance->list, &sta2x11_instance_list);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index c2da3eb4826e8..df8085b50df10 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -104,7 +104,7 @@ static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
-static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
 {
 	int rc;
 	unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
@@ -130,132 +130,6 @@ static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
 	return 0;
 }
 
-enum xen_swiotlb_err {
-	XEN_SWIOTLB_UNKNOWN = 0,
-	XEN_SWIOTLB_ENOMEM,
-	XEN_SWIOTLB_EFIXUP
-};
-
-static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
-{
-	switch (err) {
-	case XEN_SWIOTLB_ENOMEM:
-		return "Cannot allocate Xen-SWIOTLB buffer\n";
-	case XEN_SWIOTLB_EFIXUP:
-		return "Failed to get contiguous memory for DMA from Xen!\n"\
-		    "You either: don't have the permissions, do not have"\
-		    " enough free memory under 4GB, or the hypervisor memory"\
-		    " is too fragmented!";
-	default:
-		break;
-	}
-	return "";
-}
-
-int xen_swiotlb_init(void)
-{
-	enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
-	unsigned long bytes = swiotlb_size_or_default();
-	unsigned long nslabs = bytes >> IO_TLB_SHIFT;
-	unsigned int order, repeat = 3;
-	int rc = -ENOMEM;
-	char *start;
-
-	if (io_tlb_default_mem.nslabs) {
-		pr_warn("swiotlb buffer already initialized\n");
-		return -EEXIST;
-	}
-
-retry:
-	m_ret = XEN_SWIOTLB_ENOMEM;
-	order = get_order(bytes);
-
-	/*
-	 * Get IO TLB memory from any location.
-	 */
-#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
-#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
-	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
-		start = (void *)xen_get_swiotlb_free_pages(order);
-		if (start)
-			break;
-		order--;
-	}
-	if (!start)
-		goto exit;
-	if (order != get_order(bytes)) {
-		pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
-			(PAGE_SIZE << order) >> 20);
-		nslabs = SLABS_PER_PAGE << order;
-		bytes = nslabs << IO_TLB_SHIFT;
-	}
-
-	/*
-	 * And replace that memory with pages under 4GB.
-	 */
-	rc = xen_swiotlb_fixup(start, nslabs);
-	if (rc) {
-		free_pages((unsigned long)start, order);
-		m_ret = XEN_SWIOTLB_EFIXUP;
-		goto error;
-	}
-	rc = swiotlb_late_init_with_tbl(start, nslabs);
-	if (rc)
-		return rc;
-	return 0;
-error:
-	if (nslabs > 1024 && repeat--) {
-		/* Min is 2MB */
-		nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
-		bytes = nslabs << IO_TLB_SHIFT;
-		pr_info("Lowering to %luMB\n", bytes >> 20);
-		goto retry;
-	}
-exit:
-	pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
-	return rc;
-}
-
-#ifdef CONFIG_X86
-void __init xen_swiotlb_init_early(void)
-{
-	unsigned long bytes = swiotlb_size_or_default();
-	unsigned long nslabs = bytes >> IO_TLB_SHIFT;
-	unsigned int repeat = 3;
-	char *start;
-	int rc;
-
-retry:
-	/*
-	 * Get IO TLB memory from any location.
-	 */
-	start = memblock_alloc(PAGE_ALIGN(bytes),
-			       IO_TLB_SEGSIZE << IO_TLB_SHIFT);
-	if (!start)
-		panic("%s: Failed to allocate %lu bytes\n",
-		      __func__, PAGE_ALIGN(bytes));
-
-	/*
-	 * And replace that memory with pages under 4GB.
-	 */
-	rc = xen_swiotlb_fixup(start, nslabs);
-	if (rc) {
-		memblock_free(start, PAGE_ALIGN(bytes));
-		if (nslabs > 1024 && repeat--) {
-			/* Min is 2MB */
-			nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
-			bytes = nslabs << IO_TLB_SHIFT;
-			pr_info("Lowering to %luMB\n", bytes >> 20);
-			goto retry;
-		}
-		panic("%s (rc:%d)", xen_swiotlb_error(XEN_SWIOTLB_EFIXUP), rc);
-	}
-
-	if (swiotlb_init_with_tbl(start, nslabs, SWIOTLB_VERBOSE))
-		panic("Cannot allocate SWIOTLB buffer");
-}
-#endif /* CONFIG_X86 */
-
 static void *
 xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 			   dma_addr_t *dma_handle, gfp_t flags,
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index ee655f2e4d28b..919cf82ed978e 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -34,10 +34,11 @@ struct scatterlist;
 /* default to 64MB */
 #define IO_TLB_DEFAULT_SIZE (64UL<<20)
 
-int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags);
 unsigned long swiotlb_size_or_default(void);
-extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
-int swiotlb_init_late(size_t size, gfp_t gfp_mask);
+int swiotlb_init_late(size_t size, gfp_t gfp_mask,
+		int (*remap)(void *tlb, unsigned long nslabs));
+void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
+		int (*remap)(void *tlb, unsigned long nslabs));
 extern void __init swiotlb_update_mem_attributes(void);
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
diff --git a/include/xen/arm/page.h b/include/xen/arm/page.h
index ac1b654705631..7e199c6656b90 100644
--- a/include/xen/arm/page.h
+++ b/include/xen/arm/page.h
@@ -115,6 +115,5 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 bool xen_arch_need_swiotlb(struct device *dev,
 			   phys_addr_t phys,
 			   dma_addr_t dev_addr);
-unsigned long xen_get_swiotlb_free_pages(unsigned int order);
 
 #endif /* _ASM_ARM_XEN_PAGE_H */
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index b3e647f86e3e2..590ceb923f0c8 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -10,8 +10,12 @@ void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle,
 void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
 			     size_t size, enum dma_data_direction dir);
 
-int xen_swiotlb_init(void);
-void __init xen_swiotlb_init_early(void);
+#ifdef CONFIG_SWIOTLB_XEN
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs);
+#else
+#define xen_swiotlb_fixup NULL
+#endif
+
 extern const struct dma_map_ops xen_swiotlb_dma_ops;
 
 #endif /* __LINUX_SWIOTLB_XEN_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index ec200e40fc397..35ee2318ea563 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -234,40 +234,17 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
 	return;
 }
 
-int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs,
-		unsigned int flags)
-{
-	struct io_tlb_mem *mem = &io_tlb_default_mem;
-	size_t alloc_size;
-
-	if (swiotlb_force_disable)
-		return 0;
-
-	/* protect against double initialization */
-	if (WARN_ON_ONCE(mem->nslabs))
-		return -ENOMEM;
-
-	alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs));
-	mem->slots = memblock_alloc(alloc_size, PAGE_SIZE);
-	if (!mem->slots)
-		panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
-		      __func__, alloc_size, PAGE_SIZE);
-
-	swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, false);
-	mem->force_bounce = flags & SWIOTLB_FORCE;
-
-	if (flags & SWIOTLB_VERBOSE)
-		swiotlb_print_info();
-	return 0;
-}
-
 /*
  * Statically reserve bounce buffer space and initialize bounce buffer data
  * structures for the software IO TLB used to implement the DMA API.
  */
-void __init swiotlb_init(bool addressing_limit, unsigned int flags)
+void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
+		int (*remap)(void *tlb, unsigned long nslabs))
 {
-	size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT);
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
+	unsigned long nslabs = default_nslabs;
+	size_t alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs));
+	size_t bytes;
 	void *tlb;
 
 	if (!addressing_limit && !swiotlb_force_bounce)
@@ -275,23 +252,48 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags)
 	if (swiotlb_force_disable)
 		return;
 
+	/* protect against double initialization */
+	if (WARN_ON_ONCE(mem->nslabs))
+		return;
+
 	/*
 	 * By default allocate the bonuce buffer memory from low memory.
 	 */
+retry:
+	bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT);
 	if (flags & SWIOTLB_ANY)
 		tlb = memblock_alloc(bytes, PAGE_SIZE);
 	else
 		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
 	if (!tlb)
-		goto fail;
-	if (swiotlb_init_with_tbl(tlb, default_nslabs, flags))
-		goto fail_free_mem;
-	return;
+		panic("%s: failed to allocate tlb structure\n", __func__);
+
+	if (remap && remap(tlb, nslabs) < 0) {
+		memblock_free(tlb, PAGE_ALIGN(bytes));
+
+		/* Min is 2MB */
+		if (nslabs <= 1024)
+			panic("%s: Failed to remap %zu bytes\n",
+			      __func__, bytes);
+		nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
+		goto retry;
+	}
+
+	mem->slots = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!mem->slots)
+		panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
+		      __func__, alloc_size, PAGE_SIZE);
 
-fail_free_mem:
-	memblock_free(tlb, bytes);
-fail:
-	pr_warn("Cannot allocate buffer");
+	swiotlb_init_io_tlb_mem(mem, __pa(tlb), default_nslabs, false);
+	mem->force_bounce = flags & SWIOTLB_FORCE;
+
+	if (flags & SWIOTLB_VERBOSE)
+		swiotlb_print_info();
+}
+
+void __init swiotlb_init(bool addressing_limit, unsigned int flags)
+{
+	return swiotlb_init_remap(addressing_limit, flags, NULL);
 }
 
 /*
@@ -299,8 +301,10 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags)
  * initialize the swiotlb later using the slab allocator if needed.
  * This should be just like above, but with some error catching.
  */
-int swiotlb_init_late(size_t size, gfp_t gfp_mask)
+int swiotlb_init_late(size_t size, gfp_t gfp_mask,
+		int (*remap)(void *tlb, unsigned long nslabs))
 {
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
 	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
 	unsigned long bytes;
 	unsigned char *vstart = NULL;
@@ -310,9 +314,14 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask)
 	if (swiotlb_force_disable)
 		return 0;
 
+	/* protect against double initialization */
+	if (WARN_ON_ONCE(mem->nslabs))
+		return -ENOMEM;
+
 	/*
 	 * Get IO TLB memory from the low pages
 	 */
+retry:
 	order = get_order(nslabs << IO_TLB_SHIFT);
 	nslabs = SLABS_PER_PAGE << order;
 	bytes = nslabs << IO_TLB_SHIFT;
@@ -333,33 +342,28 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask)
 			(PAGE_SIZE << order) >> 20);
 		nslabs = SLABS_PER_PAGE << order;
 	}
-	rc = swiotlb_late_init_with_tbl(vstart, nslabs);
-	if (rc)
-		free_pages((unsigned long)vstart, order);
-
-	return rc;
-}
-
-int
-swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
-{
-	struct io_tlb_mem *mem = &io_tlb_default_mem;
-	unsigned long bytes = nslabs << IO_TLB_SHIFT;
 
-	if (swiotlb_force_disable)
-		return 0;
+	if (remap)
+		rc = remap(vstart, nslabs);
+	if (rc) {
+		free_pages((unsigned long)vstart, order);
 
-	/* protect against double initialization */
-	if (WARN_ON_ONCE(mem->nslabs))
-		return -ENOMEM;
+		/* Min is 2MB */
+		if (nslabs <= 1024)
+			return rc;
+		nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
+		goto retry;
+	}
 
 	mem->slots = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 		get_order(array_size(sizeof(*mem->slots), nslabs)));
-	if (!mem->slots)
+	if (!mem->slots) {
+		free_pages((unsigned long)vstart, order);
 		return -ENOMEM;
+	}
 
-	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
-	swiotlb_init_io_tlb_mem(mem, virt_to_phys(tlb), nslabs, true);
+	set_memory_decrypted((unsigned long)vstart, bytes >> PAGE_SHIFT);
+	swiotlb_init_io_tlb_mem(mem, virt_to_phys(vstart), nslabs, true);
 
 	swiotlb_print_info();
 	return 0;
-- 
2.30.2

Re: [PATCH 10/11] swiotlb: merge swiotlb-xen initialization into swiotlb

[Anshuman Khandual]

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> Allow to pass a remap argument to the swiotlb initialization functions
> to handle the Xen/x86 remap case.  ARM/ARM64 never did any remapping
> from xen_swiotlb_fixup, so we don't even need that quirk.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/arm/xen/mm.c               |  23 +++---
>  arch/x86/include/asm/xen/page.h |   5 --
>  arch/x86/kernel/pci-dma.c       |  27 ++++---
>  arch/x86/pci/sta2x11-fixup.c    |   2 +-
>  drivers/xen/swiotlb-xen.c       | 128 +-------------------------------
>  include/linux/swiotlb.h         |   7 +-
>  include/xen/arm/page.h          |   1 -
>  include/xen/swiotlb-xen.h       |   8 +-
>  kernel/dma/swiotlb.c            | 120 +++++++++++++++---------------
>  9 files changed, 102 insertions(+), 219 deletions(-)

checkpatch.pl has some warnings here.

ERROR: trailing whitespace
#151: FILE: arch/x86/kernel/pci-dma.c:217:
+ $

WARNING: please, no spaces at the start of a line
#151: FILE: arch/x86/kernel/pci-dma.c:217:
+ $

total: 1 errors, 1 warnings, 470 lines checked

[PATCH 11/11] x86: remove cruft from <asm/dma-mapping.h>

[Christoph Hellwig]

<asm/dma-mapping.h> gets pulled in by all drivers using the DMA API.
Remove x86 internal variables and unnecessary includes from it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/dma-mapping.h | 11 -----------
 arch/x86/include/asm/iommu.h       |  2 ++
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 256fd8115223d..1c66708e30623 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -2,17 +2,6 @@
 #ifndef _ASM_X86_DMA_MAPPING_H
 #define _ASM_X86_DMA_MAPPING_H
 
-/*
- * IOMMU interface. See Documentation/core-api/dma-api-howto.rst and
- * Documentation/core-api/dma-api.rst for documentation.
- */
-
-#include <linux/scatterlist.h>
-#include <asm/io.h>
-
-extern int iommu_merge;
-extern int panic_on_overflow;
-
 extern const struct dma_map_ops *dma_ops;
 
 static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index dba89ed40d38d..0bef44d30a278 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -8,6 +8,8 @@
 
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
+extern int iommu_merge;
+extern int panic_on_overflow;
 
 #ifdef CONFIG_SWIOTLB
 extern bool x86_swiotlb_enable;
-- 
2.30.2

Re: cleanup swiotlb initialization

[Boris Ostrovsky]

On 2/22/22 10:35 AM, Christoph Hellwig wrote:
> Hi all,
>
> this series tries to clean up the swiotlb initialization, including
> that of swiotlb-xen.  To get there is also removes the x86 iommu table
> infrastructure that massively obsfucates the initialization path.
>
> Git tree:
>
>      git://git.infradead.org/users/hch/misc.git swiotlb-init-cleanup


I haven't had a chance to look at this yet but this crashes as dom0:


[   37.377313] BUG: unable to handle page fault for address: ffffc90042880018
[   37.378219] #PF: supervisor read access in kernel mode
[   37.378219] #PF: error_code(0x0000) - not-present page
[   37.378219] PGD 7c2f2ee067 P4D 7c2f2ee067 PUD 7bf019b067 PMD 105a30067 PTE 0
[   37.378219] Oops: 0000 [#1] PREEMPT SMP NOPTI
[   37.378219] CPU: 14 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc5swiotlb #9
[   37.378219] Hardware name: Oracle Corporation ORACLE SERVER E1-2c/ASY,Generic,SM,E1-2c, BIOS 49004900 12/23/2020
[   37.378219] RIP: e030:init_iommu_one+0x248/0x2f0
[   37.378219] Code: 48 89 43 68 48 85 c0 74 c4 be 00 20 00 00 48 89 df e8 ea ee ff ff 48 89 43 78 48 85 c0 74 ae c6 83 98 00 00 00 00 48 8b 43 38 <48> 8b 40 18 a8 01 74 07 83 8b a8 04 00 00 01 f6 83 a8 04 00 00 01
[   37.378219] RSP: e02b:ffffc9004044bd18 EFLAGS: 00010286
[   37.378219] RAX: ffffc90042880000 RBX: ffff888107260800 RCX: 0000000000000000
[   37.378219] RDX: 0000000080000000 RSI: ffffea00041cab80 RDI: 00000000ffffffff
[   37.378219] RBP: ffffc9004044bd38 R08: 0000000000000901 R09: ffffea00041cab00
[   37.378219] R10: 0000000000000002 R11: 0000000000000000 R12: ffffc90040435008
[   37.378219] R13: 0000000000080000 R14: 00000000efa00000 R15: 0000000000000000
[   37.378219] FS:  0000000000000000(0000) GS:ffff88fef4180000(0000) knlGS:0000000000000000
[   37.378219] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
[   37.378219] CR2: ffffc90042880018 CR3: 000000000260a000 CR4: 0000000000050660
[   37.378219] Call Trace:
[   37.378219]  <TASK>
[   37.378219]  early_amd_iommu_init+0x3c5/0x72d
[   37.378219]  ? iommu_setup+0x284/0x284
[   37.378219]  state_next+0x158/0x68f
[   37.378219]  ? iommu_setup+0x284/0x284
[   37.378219]  iommu_go_to_state+0x28/0x2d
[   37.378219]  amd_iommu_init+0x15/0x4b
[   37.378219]  ? iommu_setup+0x284/0x284
[   37.378219]  pci_iommu_init+0x12/0x37
[   37.378219]  do_one_initcall+0x48/0x210
[   37.378219]  kernel_init_freeable+0x229/0x28c
[   37.378219]  ? rest_init+0xe0/0xe0
[   37.963966]  kernel_init+0x1a/0x130
[   37.979415]  ret_from_fork+0x22/0x30
[   37.991436]  </TASK>
[   37.999465] Modules linked in:
[   38.007413] CR2: ffffc90042880018
[   38.019416] ---[ end trace 0000000000000000 ]---
[   38.023418] RIP: e030:init_iommu_one+0x248/0x2f0
[   38.023418] Code: 48 89 43 68 48 85 c0 74 c4 be 00 20 00 00 48 89 df e8 ea ee ff ff 48 89 43 78 48 85 c0 74 ae c6 83 98 00 00 00 00 48 8b 43 38 <48> 8b 40 18 a8 01 74 07 83 8b a8 04 00 00 01 f6 83 a8 04 00 00 01
[   38.023418] RSP: e02b:ffffc9004044bd18 EFLAGS: 00010286
[   38.023418] RAX: ffffc90042880000 RBX: ffff888107260800 RCX: 0000000000000000
[   38.155413] RDX: 0000000080000000 RSI: ffffea00041cab80 RDI: 00000000ffffffff
[   38.175965] Freeing initrd memory: 62640K
[   38.155413] RBP: ffffc9004044bd38 R08: 0000000000000901 R09: ffffea00041cab00
[   38.155413] R10: 0000000000000002 R11: 0000000000000000 R12: ffffc90040435008
[   38.155413] R13: 0000000000080000 R14: 00000000efa00000 R15: 0000000000000000
[   38.155413] FS:  0000000000000000(0000) GS:ffff88fef4180000(0000) knlGS:0000000000000000
[   38.287414] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
[   38.309557] CR2: ffffc90042880018 CR3: 000000000260a000 CR4: 0000000000050660
[   38.332403] Kernel panic - not syncing: Fatal exception
[   38.351414] Rebooting in 20 seconds..



-boris

Re: cleanup swiotlb initialization

[Christoph Hellwig]

Thanks.

This looks really strange as early_amd_iommu_init should not interact much
with the changes.  I'll see if I can find a AMD system to test on.

On Wed, Feb 23, 2022 at 07:57:49PM -0500, Boris Ostrovsky wrote:
> [   37.377313] BUG: unable to handle page fault for address: ffffc90042880018
> [   37.378219] #PF: supervisor read access in kernel mode
> [   37.378219] #PF: error_code(0x0000) - not-present page
> [   37.378219] PGD 7c2f2ee067 P4D 7c2f2ee067 PUD 7bf019b067 PMD 105a30067 PTE 0
> [   37.378219] Oops: 0000 [#1] PREEMPT SMP NOPTI
> [   37.378219] CPU: 14 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc5swiotlb #9
> [   37.378219] Hardware name: Oracle Corporation ORACLE SERVER E1-2c/ASY,Generic,SM,E1-2c, BIOS 49004900 12/23/2020
> [   37.378219] RIP: e030:init_iommu_one+0x248/0x2f0
> [   37.378219] Code: 48 89 43 68 48 85 c0 74 c4 be 00 20 00 00 48 89 df e8 ea ee ff ff 48 89 43 78 48 85 c0 74 ae c6 83 98 00 00 00 00 48 8b 43 38 <48> 8b 40 18 a8 01 74 07 83 8b a8 04 00 00 01 f6 83 a8 04 00 00 01
> [   37.378219] RSP: e02b:ffffc9004044bd18 EFLAGS: 00010286
> [   37.378219] RAX: ffffc90042880000 RBX: ffff888107260800 RCX: 0000000000000000
> [   37.378219] RDX: 0000000080000000 RSI: ffffea00041cab80 RDI: 00000000ffffffff
> [   37.378219] RBP: ffffc9004044bd38 R08: 0000000000000901 R09: ffffea00041cab00
> [   37.378219] R10: 0000000000000002 R11: 0000000000000000 R12: ffffc90040435008
> [   37.378219] R13: 0000000000080000 R14: 00000000efa00000 R15: 0000000000000000
> [   37.378219] FS:  0000000000000000(0000) GS:ffff88fef4180000(0000) knlGS:0000000000000000
> [   37.378219] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   37.378219] CR2: ffffc90042880018 CR3: 000000000260a000 CR4: 0000000000050660
> [   37.378219] Call Trace:
> [   37.378219]  <TASK>
> [   37.378219]  early_amd_iommu_init+0x3c5/0x72d
> [   37.378219]  ? iommu_setup+0x284/0x284
> [   37.378219]  state_next+0x158/0x68f
> [   37.378219]  ? iommu_setup+0x284/0x284
> [   37.378219]  iommu_go_to_state+0x28/0x2d
> [   37.378219]  amd_iommu_init+0x15/0x4b
> [   37.378219]  ? iommu_setup+0x284/0x284
> [   37.378219]  pci_iommu_init+0x12/0x37
> [   37.378219]  do_one_initcall+0x48/0x210
> [   37.378219]  kernel_init_freeable+0x229/0x28c
> [   37.378219]  ? rest_init+0xe0/0xe0
> [   37.963966]  kernel_init+0x1a/0x130
> [   37.979415]  ret_from_fork+0x22/0x30
> [   37.991436]  </TASK>
> [   37.999465] Modules linked in:
> [   38.007413] CR2: ffffc90042880018
> [   38.019416] ---[ end trace 0000000000000000 ]---
> [   38.023418] RIP: e030:init_iommu_one+0x248/0x2f0
> [   38.023418] Code: 48 89 43 68 48 85 c0 74 c4 be 00 20 00 00 48 89 df e8 ea ee ff ff 48 89 43 78 48 85 c0 74 ae c6 83 98 00 00 00 00 48 8b 43 38 <48> 8b 40 18 a8 01 74 07 83 8b a8 04 00 00 01 f6 83 a8 04 00 00 01
> [   38.023418] RSP: e02b:ffffc9004044bd18 EFLAGS: 00010286
> [   38.023418] RAX: ffffc90042880000 RBX: ffff888107260800 RCX: 0000000000000000
> [   38.155413] RDX: 0000000080000000 RSI: ffffea00041cab80 RDI: 00000000ffffffff
> [   38.175965] Freeing initrd memory: 62640K
> [   38.155413] RBP: ffffc9004044bd38 R08: 0000000000000901 R09: ffffea00041cab00
> [   38.155413] R10: 0000000000000002 R11: 0000000000000000 R12: ffffc90040435008
> [   38.155413] R13: 0000000000080000 R14: 00000000efa00000 R15: 0000000000000000
> [   38.155413] FS:  0000000000000000(0000) GS:ffff88fef4180000(0000) knlGS:0000000000000000
> [   38.287414] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   38.309557] CR2: ffffc90042880018 CR3: 000000000260a000 CR4: 0000000000050660
> [   38.332403] Kernel panic - not syncing: Fatal exception
> [   38.351414] Rebooting in 20 seconds..
>
>
>
> -boris
---end quoted text---

Re: cleanup swiotlb initialization

[Boris Ostrovsky]

On 2/24/22 10:58 AM, Christoph Hellwig wrote:
> Thanks.
>
> This looks really strange as early_amd_iommu_init should not interact much
> with the changes.  I'll see if I can find a AMD system to test on.


Just to be clear: this crashes only as dom0. Boots fine as baremetal.


-boris


>
> On Wed, Feb 23, 2022 at 07:57:49PM -0500, Boris Ostrovsky wrote:
>> [   37.377313] BUG: unable to handle page fault for address: ffffc90042880018
>> [   37.378219] #PF: supervisor read access in kernel mode
>> [   37.378219] #PF: error_code(0x0000) - not-present page
>> [   37.378219] PGD 7c2f2ee067 P4D 7c2f2ee067 PUD 7bf019b067 PMD 105a30067 PTE 0
>> [   37.378219] Oops: 0000 [#1] PREEMPT SMP NOPTI
>> [   37.378219] CPU: 14 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc5swiotlb #9
>> [   37.378219] Hardware name: Oracle Corporation ORACLE SERVER E1-2c/ASY,Generic,SM,E1-2c, BIOS 49004900 12/23/2020
>> [   37.378219] RIP: e030:init_iommu_one+0x248/0x2f0
>> [   37.378219] Code: 48 89 43 68 48 85 c0 74 c4 be 00 20 00 00 48 89 df e8 ea ee ff ff 48 89 43 78 48 85 c0 74 ae c6 83 98 00 00 00 00 48 8b 43 38 <48> 8b 40 18 a8 01 74 07 83 8b a8 04 00 00 01 f6 83 a8 04 00 00 01
>> [   37.378219] RSP: e02b:ffffc9004044bd18 EFLAGS: 00010286
>> [   37.378219] RAX: ffffc90042880000 RBX: ffff888107260800 RCX: 0000000000000000
>> [   37.378219] RDX: 0000000080000000 RSI: ffffea00041cab80 RDI: 00000000ffffffff
>> [   37.378219] RBP: ffffc9004044bd38 R08: 0000000000000901 R09: ffffea00041cab00
>> [   37.378219] R10: 0000000000000002 R11: 0000000000000000 R12: ffffc90040435008
>> [   37.378219] R13: 0000000000080000 R14: 00000000efa00000 R15: 0000000000000000
>> [   37.378219] FS:  0000000000000000(0000) GS:ffff88fef4180000(0000) knlGS:0000000000000000
>> [   37.378219] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [   37.378219] CR2: ffffc90042880018 CR3: 000000000260a000 CR4: 0000000000050660
>> [   37.378219] Call Trace:
>> [   37.378219]  <TASK>
>> [   37.378219]  early_amd_iommu_init+0x3c5/0x72d
>> [   37.378219]  ? iommu_setup+0x284/0x284
>> [   37.378219]  state_next+0x158/0x68f
>> [   37.378219]  ? iommu_setup+0x284/0x284
>> [   37.378219]  iommu_go_to_state+0x28/0x2d
>> [   37.378219]  amd_iommu_init+0x15/0x4b
>> [   37.378219]  ? iommu_setup+0x284/0x284
>> [   37.378219]  pci_iommu_init+0x12/0x37
>> [   37.378219]  do_one_initcall+0x48/0x210
>> [   37.378219]  kernel_init_freeable+0x229/0x28c
>> [   37.378219]  ? rest_init+0xe0/0xe0
>> [   37.963966]  kernel_init+0x1a/0x130
>> [   37.979415]  ret_from_fork+0x22/0x30
>> [   37.991436]  </TASK>
>> [   37.999465] Modules linked in:
>> [   38.007413] CR2: ffffc90042880018
>> [   38.019416] ---[ end trace 0000000000000000 ]---
>> [   38.023418] RIP: e030:init_iommu_one+0x248/0x2f0
>> [   38.023418] Code: 48 89 43 68 48 85 c0 74 c4 be 00 20 00 00 48 89 df e8 ea ee ff ff 48 89 43 78 48 85 c0 74 ae c6 83 98 00 00 00 00 48 8b 43 38 <48> 8b 40 18 a8 01 74 07 83 8b a8 04 00 00 01 f6 83 a8 04 00 00 01
>> [   38.023418] RSP: e02b:ffffc9004044bd18 EFLAGS: 00010286
>> [   38.023418] RAX: ffffc90042880000 RBX: ffff888107260800 RCX: 0000000000000000
>> [   38.155413] RDX: 0000000080000000 RSI: ffffea00041cab80 RDI: 00000000ffffffff
>> [   38.175965] Freeing initrd memory: 62640K
>> [   38.155413] RBP: ffffc9004044bd38 R08: 0000000000000901 R09: ffffea00041cab00
>> [   38.155413] R10: 0000000000000002 R11: 0000000000000000 R12: ffffc90040435008
>> [   38.155413] R13: 0000000000080000 R14: 00000000efa00000 R15: 0000000000000000
>> [   38.155413] FS:  0000000000000000(0000) GS:ffff88fef4180000(0000) knlGS:0000000000000000
>> [   38.287414] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [   38.309557] CR2: ffffc90042880018 CR3: 000000000260a000 CR4: 0000000000050660
>> [   38.332403] Kernel panic - not syncing: Fatal exception
>> [   38.351414] Rebooting in 20 seconds..
>>
>>
>>
>> -boris
> ---end quoted text---
>

Re: cleanup swiotlb initialization

[Christoph Hellwig]

On Thu, Feb 24, 2022 at 11:18:33AM -0500, Boris Ostrovsky wrote:
>
> On 2/24/22 10:58 AM, Christoph Hellwig wrote:
>> Thanks.
>>
>> This looks really strange as early_amd_iommu_init should not interact much
>> with the changes.  I'll see if I can find a AMD system to test on.
>
>
> Just to be clear: this crashes only as dom0. Boots fine as baremetal.

Ah.  I can gues what this might be.  On Xen the hypervisor controls the
IOMMU and we should never end up initializing it in Linux, right?

Re: cleanup swiotlb initialization

[Boris Ostrovsky]

On 2/24/22 11:39 AM, Christoph Hellwig wrote:
> On Thu, Feb 24, 2022 at 11:18:33AM -0500, Boris Ostrovsky wrote:
>> On 2/24/22 10:58 AM, Christoph Hellwig wrote:
>>> Thanks.
>>>
>>> This looks really strange as early_amd_iommu_init should not interact much
>>> with the changes.  I'll see if I can find a AMD system to test on.
>>
>> Just to be clear: this crashes only as dom0. Boots fine as baremetal.
> Ah.  I can gues what this might be.  On Xen the hypervisor controls the
> IOMMU and we should never end up initializing it in Linux, right?


Right, we shouldn't be in that code path.


-boris

Re: cleanup swiotlb initialization

[Christoph Hellwig]

On Thu, Feb 24, 2022 at 12:07:26PM -0500, Boris Ostrovsky wrote:
>>> Just to be clear: this crashes only as dom0. Boots fine as baremetal.
>> Ah.  I can gues what this might be.  On Xen the hypervisor controls the
>> IOMMU and we should never end up initializing it in Linux, right?
>
>
> Right, we shouldn't be in that code path.

Can you try the patch below on top of the series?


diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index b849f11a756d0..f88c9a4a5ed12 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -47,22 +47,6 @@ static unsigned int x86_swiotlb_flags;
  */
 static void __init pci_swiotlb_detect_4gb(void)
 {
-#ifdef CONFIG_SWIOTLB_XEN
-	if (xen_pv_domain()) {
-		if (xen_initial_domain())
-			x86_swiotlb_enable = true;
-
-		if (x86_swiotlb_enable) {
-			dma_ops = &xen_swiotlb_dma_ops;
-#ifdef CONFIG_PCI
-			/* Make sure ACS will be enabled */
-			pci_request_acs();
-#endif
-		}
-		return;
-	}
-#endif /* CONFIG_SWIOTLB_XEN */
-
 	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
 	if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
 		x86_swiotlb_enable = true;
@@ -82,16 +66,36 @@ static inline void __init pci_swiotlb_detect_4gb(void)
 }
 #endif /* CONFIG_SWIOTLB */
 
+#ifdef CONFIG_SWIOTLB_XEN
+static void __init xen_swiotlb_init(void)
+{
+	if (!xen_initial_domain() && !x86_swiotlb_enable)
+		return;
+	x86_swiotlb_enable = true;
+	dma_ops = &xen_swiotlb_dma_ops;
+#ifdef CONFIG_PCI
+	/* Make sure ACS will be enabled */
+	pci_request_acs();
+#endif
+	swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
+}
+#else
+static inline void __init xen_swiotlb_init(void)
+{
+}
+#endif /* CONFIG_SWIOTLB_XEN */
+
 void __init pci_iommu_alloc(void)
 {
+	if (xen_pv_domain()) {
+		xen_swiotlb_init();
+		return;
+	}
 	pci_swiotlb_detect_4gb();
 	gart_iommu_hole_init();
 	amd_iommu_detect();
 	detect_intel_iommu();
-#ifdef CONFIG_SWIOTLB
-	swiotlb_init_remap(x86_swiotlb_enable, x86_swiotlb_flags,
-			   xen_pv_domain() ? xen_swiotlb_fixup : NULL);
-#endif
+	swiotlb_init(x86_swiotlb_enable, x86_swiotlb_flags);
 }
 
 /*

Re: cleanup swiotlb initialization

[Boris Ostrovsky]

On 2/25/22 3:47 AM, Christoph Hellwig wrote:
> On Thu, Feb 24, 2022 at 12:07:26PM -0500, Boris Ostrovsky wrote:
>>>> Just to be clear: this crashes only as dom0. Boots fine as baremetal.
>>> Ah.  I can gues what this might be.  On Xen the hypervisor controls the
>>> IOMMU and we should never end up initializing it in Linux, right?
>>
>> Right, we shouldn't be in that code path.
> Can you try the patch below on top of the series?
>

Yes, this makes dom0 boot fine.


(It also addresses something I wanted to mention while looking at the patches, which was to remove Xen initialization code from pci_swiotlb_detect_4gb() since it had noting to do with what the routine's name implies.)


-boris

cleanup swiotlb initialization v2

[Christoph Hellwig]

Hi all,

this series tries to clean up the swiotlb initialization, including
that of swiotlb-xen.  To get there is also removes the x86 iommu table
infrastructure that massively obsfucates the initialization path.

Git tree:

    git://git.infradead.org/users/hch/misc.git swiotlb-init-cleanup

Gitweb:

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

Changes since v1:
 - skip IOMMU initialization on Xen PV kernels
 - various small whitespace / typo fixes

Diffstat:
 arch/ia64/include/asm/iommu_table.h      |    7 -
 arch/x86/include/asm/iommu_table.h       |  102 -------------------
 arch/x86/include/asm/swiotlb.h           |   30 -----
 arch/x86/kernel/pci-iommu_table.c        |   77 --------------
 arch/x86/kernel/pci-swiotlb.c            |   77 --------------
 arch/x86/xen/pci-swiotlb-xen.c           |   96 ------------------
 b/arch/arm/mm/init.c                     |    6 -
 b/arch/arm/xen/mm.c                      |   23 ++--
 b/arch/arm64/mm/init.c                   |    6 -
 b/arch/ia64/mm/init.c                    |    4 
 b/arch/mips/cavium-octeon/dma-octeon.c   |   15 --
 b/arch/mips/loongson64/dma.c             |    2 
 b/arch/mips/pci/pci-octeon.c             |    2 
 b/arch/mips/sibyte/common/dma.c          |    2 
 b/arch/powerpc/include/asm/svm.h         |    4 
 b/arch/powerpc/include/asm/swiotlb.h     |    1 
 b/arch/powerpc/mm/mem.c                  |    6 -
 b/arch/powerpc/platforms/pseries/setup.c |    3 
 b/arch/powerpc/platforms/pseries/svm.c   |   26 ----
 b/arch/riscv/mm/init.c                   |    8 -
 b/arch/s390/mm/init.c                    |    3 
 b/arch/x86/include/asm/dma-mapping.h     |   12 --
 b/arch/x86/include/asm/gart.h            |    5 
 b/arch/x86/include/asm/iommu.h           |    8 +
 b/arch/x86/include/asm/xen/page.h        |    5 
 b/arch/x86/include/asm/xen/swiotlb-xen.h |    2 
 b/arch/x86/kernel/Makefile               |    2 
 b/arch/x86/kernel/amd_gart_64.c          |    5 
 b/arch/x86/kernel/aperture_64.c          |   14 --
 b/arch/x86/kernel/cpu/mshyperv.c         |    8 -
 b/arch/x86/kernel/pci-dma.c              |  109 ++++++++++++++++----
 b/arch/x86/kernel/tboot.c                |    1 
 b/arch/x86/kernel/vmlinux.lds.S          |   12 --
 b/arch/x86/mm/mem_encrypt_amd.c          |    3 
 b/arch/x86/pci/sta2x11-fixup.c           |    2 
 b/arch/x86/xen/Makefile                  |    2 
 b/drivers/iommu/amd/init.c               |    6 -
 b/drivers/iommu/amd/iommu.c              |    5 
 b/drivers/iommu/intel/dmar.c             |    6 -
 b/drivers/xen/swiotlb-xen.c              |  132 -------------------------
 b/include/linux/dmar.h                   |    6 -
 b/include/linux/swiotlb.h                |   22 ++--
 b/include/trace/events/swiotlb.h         |   29 +----
 b/include/xen/arm/page.h                 |    1 
 b/include/xen/swiotlb-xen.h              |    8 +
 b/kernel/dma/direct.h                    |    2 
 b/kernel/dma/swiotlb.c                   |  163 +++++++++++++++----------------
 47 files changed, 253 insertions(+), 817 deletions(-)

[PATCH 06/11] MIPS/octeon: use swiotlb_init instead of open coding it

[Christoph Hellwig]

Use the generic swiotlb initialization helper instead of open coding it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/mips/cavium-octeon/dma-octeon.c | 15 ++-------------
 arch/mips/pci/pci-octeon.c           |  2 +-
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
index df70308db0e69..fb7547e217263 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -186,15 +186,12 @@ phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
 	return daddr;
 }
 
-char *octeon_swiotlb;
-
 void __init plat_swiotlb_setup(void)
 {
 	phys_addr_t start, end;
 	phys_addr_t max_addr;
 	phys_addr_t addr_size;
 	size_t swiotlbsize;
-	unsigned long swiotlb_nslabs;
 	u64 i;
 
 	max_addr = 0;
@@ -236,15 +233,7 @@ void __init plat_swiotlb_setup(void)
 	if (OCTEON_IS_OCTEON2() && max_addr >= 0x100000000ul)
 		swiotlbsize = 64 * (1<<20);
 #endif
-	swiotlb_nslabs = swiotlbsize >> IO_TLB_SHIFT;
-	swiotlb_nslabs = ALIGN(swiotlb_nslabs, IO_TLB_SEGSIZE);
-	swiotlbsize = swiotlb_nslabs << IO_TLB_SHIFT;
-
-	octeon_swiotlb = memblock_alloc_low(swiotlbsize, PAGE_SIZE);
-	if (!octeon_swiotlb)
-		panic("%s: Failed to allocate %zu bytes align=%lx\n",
-		      __func__, swiotlbsize, PAGE_SIZE);
 
-	if (swiotlb_init_with_tbl(octeon_swiotlb, swiotlb_nslabs, 1) == -ENOMEM)
-		panic("Cannot allocate SWIOTLB buffer");
+	swiotlb_adjust_size(swiotlbsize);
+	swiotlb_init(1);
 }
diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index fc29b85cfa926..e457a18cbdc59 100644
--- a/arch/mips/pci/pci-octeon.c
+++ b/arch/mips/pci/pci-octeon.c
@@ -664,7 +664,7 @@ static int __init octeon_pci_setup(void)
 
 		/* BAR1 movable regions contiguous to cover the swiotlb */
 		octeon_bar1_pci_phys =
-			virt_to_phys(octeon_swiotlb) & ~((1ull << 22) - 1);
+			io_tlb_default_mem.start & ~((1ull << 22) - 1);
 
 		for (index = 0; index < 32; index++) {
 			union cvmx_pci_bar1_indexx bar1_index;
-- 
2.30.2