thr3ads.net - Linux Virtualization - [PATCH 35/35] x86: Don't panic if can not alloc buffer for swiotlb [Jan 2013]

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Yinghai Lu

2013-Jan-24 20:20 UTC

[PATCH 35/35] x86: Don't panic if can not alloc buffer for swiotlb

Normal boot path on system with iommu support:
swiotlb buffer will be allocated early at first and then try to initialize
iommu, if iommu for intel or AMD could setup properly, swiotlb buffer
will be freed.

The early allocating is with bootmem, and could panic when we try to use
kdump with buffer above 4G only, or with memmap to limit mem under 4G.
for example: memmap=4095M$1M to remove memory under 4G.

According to Eric, add _nopanic version and no_iotlb_memory to fail
map single later if swiotlb is still needed.

-v2: don't pass nopanic, and use -ENOMEM return value according to Eric.
     panic early instead of using swiotlb_full to panic...according to
Eric/Konrad.
-v3: make swiotlb_init to be notpanic, but will affect:
     arm64, ia64, powerpc, tile, unicore32, x86.
-v4: cleanup swiotlb_init by removing swiotlb_init_with_default_size.

Suggested-by: Eric W. Biederman <ebiederm at xmission.com>
Signed-off-by: Yinghai Lu <yinghai at kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Cc: Joerg Roedel <joro at 8bytes.org>
Cc: Ralf Baechle <ralf at linux-mips.org>
Cc: Jeremy Fitzhardinge <jeremy at goop.org>
Cc: Kyungmin Park <kyungmin.park at samsung.com>
Cc: Marek Szyprowski <m.szyprowski at samsung.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Andrzej Pietrasiewicz <andrzej.p at samsung.com>
Cc: linux-mips at linux-mips.org
Cc: xen-devel at lists.xensource.com
Cc: virtualization at lists.linux-foundation.org
Cc: Shuah Khan <shuahkhan at gmail.com>
---
 arch/mips/cavium-octeon/dma-octeon.c |    3 ++-
 drivers/xen/swiotlb-xen.c            |    4 ++-
 include/linux/swiotlb.h              |    2 +-
 lib/swiotlb.c                        |   47 +++++++++++++++++++++-------------
 4 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/arch/mips/cavium-octeon/dma-octeon.c
b/arch/mips/cavium-octeon/dma-octeon.c
index 41dd0088..02f2444 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -317,7 +317,8 @@ void __init plat_swiotlb_setup(void)
 
 	octeon_swiotlb = alloc_bootmem_low_pages(swiotlbsize);
 
-	swiotlb_init_with_tbl(octeon_swiotlb, swiotlb_nslabs, 1);
+	if (swiotlb_init_with_tbl(octeon_swiotlb, swiotlb_nslabs, 1) == -ENOMEM)
+		panic("Cannot allocate SWIOTLB buffer");
 
 	mips_dma_map_ops = &octeon_linear_dma_map_ops.dma_map_ops;
 }
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index af47e75..1d94316 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -231,7 +231,9 @@ retry:
 	}
 	start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
 	if (early) {
-		swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
+		if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
+			 verbose))
+			panic("Cannot allocate SWIOTLB buffer");
 		rc = 0;
 	} else
 		rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 071d62c..2de42f9 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -23,7 +23,7 @@ extern int swiotlb_force;
 #define IO_TLB_SHIFT 11
 
 extern void swiotlb_init(int verbose);
-extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int
verbose);
+int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
 extern unsigned long swiotlb_nr_tbl(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
 
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 196b069..bfe02b8 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -122,11 +122,18 @@ static dma_addr_t swiotlb_virt_to_bus(struct device
*hwdev,
 	return phys_to_dma(hwdev, virt_to_phys(address));
 }
 
+static bool no_iotlb_memory;
+
 void swiotlb_print_info(void)
 {
 	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 	unsigned char *vstart, *vend;
 
+	if (no_iotlb_memory) {
+		pr_warn("software IO TLB: No low mem\n");
+		return;
+	}
+
 	vstart = phys_to_virt(io_tlb_start);
 	vend = phys_to_virt(io_tlb_end);
 
@@ -136,7 +143,7 @@ void swiotlb_print_info(void)
 	       bytes >> 20, vstart, vend - 1);
 }
 
-void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
+int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 {
 	void *v_overflow_buffer;
 	unsigned long i, bytes;
@@ -150,9 +157,10 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long
nslabs, int verbose)
 	/*
 	 * Get the overflow emergency buffer
 	 */
-	v_overflow_buffer = alloc_bootmem_low_pages(PAGE_ALIGN(io_tlb_overflow));
+	v_overflow_buffer = alloc_bootmem_low_pages_nopanic(
+						PAGE_ALIGN(io_tlb_overflow));
 	if (!v_overflow_buffer)
-		panic("Cannot allocate SWIOTLB overflow buffer!\n");
+		return -ENOMEM;
 
 	io_tlb_overflow_buffer = __pa(v_overflow_buffer);
 
@@ -169,15 +177,19 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long
nslabs, int verbose)
 
 	if (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.
  */
-static void __init
-swiotlb_init_with_default_size(size_t default_size, int verbose)
+void  __init
+swiotlb_init(int verbose)
 {
+	/* default to 64MB */
+	size_t default_size = 64UL<<20;
 	unsigned char *vstart;
 	unsigned long bytes;
 
@@ -188,20 +200,16 @@ swiotlb_init_with_default_size(size_t default_size, int
verbose)
 
 	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 
-	/*
-	 * Get IO TLB memory from the low pages
-	 */
-	vstart = alloc_bootmem_low_pages(PAGE_ALIGN(bytes));
-	if (!vstart)
-		panic("Cannot allocate SWIOTLB buffer");
-
-	swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose);
-}
+	/* Get IO TLB memory from the low pages */
+	vstart = alloc_bootmem_low_pages_nopanic(PAGE_ALIGN(bytes));
+	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
+		return;
 
-void __init
-swiotlb_init(int verbose)
-{
-	swiotlb_init_with_default_size(64 * (1<<20), verbose);	/* default to
64MB */
+	if (io_tlb_start)
+		free_bootmem(io_tlb_start,
+				 PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
+	pr_warn("Cannot allocate SWIOTLB buffer");
+	no_iotlb_memory = true;
 }
 
 /*
@@ -405,6 +413,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 	unsigned long offset_slots;
 	unsigned long max_slots;
 
+	if (no_iotlb_memory)
+		panic("Can not allocate SWIOTLB buffer earlier and can't now provide
you with the DMA bounce buffer");
+
 	mask = dma_get_seg_boundary(hwdev);
 
 	tbl_dma_addr &= mask;
-- 
1.7.10.4

Konrad Rzeszutek Wilk

2013-Jan-25 16:47 UTC

head link

[PATCH 35/35] x86: Don't panic if can not alloc buffer for swiotlb

On Thu, Jan 24, 2013 at 12:20:16PM -0800, Yinghai Lu
wrote:> Normal boot path on system with iommu support:
> swiotlb buffer will be allocated early at first and then try to initialize
> iommu, if iommu for intel or AMD could setup properly, swiotlb buffer
> will be freed.
> 
> The early allocating is with bootmem, and could panic when we try to use
> kdump with buffer above 4G only, or with memmap to limit mem under 4G.
> for example: memmap=4095M$1M to remove memory under 4G.
> 
> According to Eric, add _nopanic version and no_iotlb_memory to fail
> map single later if swiotlb is still needed.
> 
> -v2: don't pass nopanic, and use -ENOMEM return value according to
Eric.
>      panic early instead of using swiotlb_full to panic...according to
Eric/Konrad.
> -v3: make swiotlb_init to be notpanic, but will affect:
>      arm64, ia64, powerpc, tile, unicore32, x86.
> -v4: cleanup swiotlb_init by removing swiotlb_init_with_default_size.
> 
> Suggested-by: Eric W. Biederman <ebiederm at xmission.com>
> Signed-off-by: Yinghai Lu <yinghai at kernel.org>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>

:-)
> Cc: Joerg Roedel <joro at 8bytes.org>
> Cc: Ralf Baechle <ralf at linux-mips.org>
> Cc: Jeremy Fitzhardinge <jeremy at goop.org>
> Cc: Kyungmin Park <kyungmin.park at samsung.com>
> Cc: Marek Szyprowski <m.szyprowski at samsung.com>
> Cc: Arnd Bergmann <arnd at arndb.de>
> Cc: Andrzej Pietrasiewicz <andrzej.p at samsung.com>
> Cc: linux-mips at linux-mips.org
> Cc: xen-devel at lists.xensource.com
> Cc: virtualization at lists.linux-foundation.org
> Cc: Shuah Khan <shuahkhan at gmail.com>
> ---
>  arch/mips/cavium-octeon/dma-octeon.c |    3 ++-
>  drivers/xen/swiotlb-xen.c            |    4 ++-
>  include/linux/swiotlb.h              |    2 +-
>  lib/swiotlb.c                        |   47
+++++++++++++++++++++-------------
>  4 files changed, 35 insertions(+), 21 deletions(-)
> 
> diff --git a/arch/mips/cavium-octeon/dma-octeon.c
b/arch/mips/cavium-octeon/dma-octeon.c
> index 41dd0088..02f2444 100644
> --- a/arch/mips/cavium-octeon/dma-octeon.c
> +++ b/arch/mips/cavium-octeon/dma-octeon.c
> @@ -317,7 +317,8 @@ void __init plat_swiotlb_setup(void)
>  
>  	octeon_swiotlb = alloc_bootmem_low_pages(swiotlbsize);
>  
> -	swiotlb_init_with_tbl(octeon_swiotlb, swiotlb_nslabs, 1);
> +	if (swiotlb_init_with_tbl(octeon_swiotlb, swiotlb_nslabs, 1) == -ENOMEM)
> +		panic("Cannot allocate SWIOTLB buffer");
>  
>  	mips_dma_map_ops = &octeon_linear_dma_map_ops.dma_map_ops;
>  }
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index af47e75..1d94316 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -231,7 +231,9 @@ retry:
>  	}
>  	start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
>  	if (early) {
> -		swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
> +		if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
> +			 verbose))
> +			panic("Cannot allocate SWIOTLB buffer");
>  		rc = 0;
>  	} else
>  		rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 071d62c..2de42f9 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -23,7 +23,7 @@ extern int swiotlb_force;
>  #define IO_TLB_SHIFT 11
>  
>  extern void swiotlb_init(int verbose);
> -extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int
verbose);
> +int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
>  extern unsigned long swiotlb_nr_tbl(void);
>  extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
>  
> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> index 196b069..bfe02b8 100644
> --- a/lib/swiotlb.c
> +++ b/lib/swiotlb.c
> @@ -122,11 +122,18 @@ static dma_addr_t swiotlb_virt_to_bus(struct device
*hwdev,
>  	return phys_to_dma(hwdev, virt_to_phys(address));
>  }
>  
> +static bool no_iotlb_memory;
> +
>  void swiotlb_print_info(void)
>  {
>  	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
>  	unsigned char *vstart, *vend;
>  
> +	if (no_iotlb_memory) {
> +		pr_warn("software IO TLB: No low mem\n");
> +		return;
> +	}
> +
>  	vstart = phys_to_virt(io_tlb_start);
>  	vend = phys_to_virt(io_tlb_end);
>  
> @@ -136,7 +143,7 @@ void swiotlb_print_info(void)
>  	       bytes >> 20, vstart, vend - 1);
>  }
>  
> -void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int
verbose)
> +int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int
verbose)
>  {
>  	void *v_overflow_buffer;
>  	unsigned long i, bytes;
> @@ -150,9 +157,10 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned
long nslabs, int verbose)
>  	/*
>  	 * Get the overflow emergency buffer
>  	 */
> -	v_overflow_buffer = alloc_bootmem_low_pages(PAGE_ALIGN(io_tlb_overflow));
> +	v_overflow_buffer = alloc_bootmem_low_pages_nopanic(
> +						PAGE_ALIGN(io_tlb_overflow));
>  	if (!v_overflow_buffer)
> -		panic("Cannot allocate SWIOTLB overflow buffer!\n");
> +		return -ENOMEM;
>  
>  	io_tlb_overflow_buffer = __pa(v_overflow_buffer);
>  
> @@ -169,15 +177,19 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned
long nslabs, int verbose)
>  
>  	if (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.
>   */
> -static void __init
> -swiotlb_init_with_default_size(size_t default_size, int verbose)
> +void  __init
> +swiotlb_init(int verbose)
>  {
> +	/* default to 64MB */
> +	size_t default_size = 64UL<<20;
>  	unsigned char *vstart;
>  	unsigned long bytes;
>  
> @@ -188,20 +200,16 @@ swiotlb_init_with_default_size(size_t default_size,
int verbose)
>  
>  	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
>  
> -	/*
> -	 * Get IO TLB memory from the low pages
> -	 */
> -	vstart = alloc_bootmem_low_pages(PAGE_ALIGN(bytes));
> -	if (!vstart)
> -		panic("Cannot allocate SWIOTLB buffer");
> -
> -	swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose);
> -}
> +	/* Get IO TLB memory from the low pages */
> +	vstart = alloc_bootmem_low_pages_nopanic(PAGE_ALIGN(bytes));
> +	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs,
verbose))
> +		return;
>  
> -void __init
> -swiotlb_init(int verbose)
> -{
> -	swiotlb_init_with_default_size(64 * (1<<20), verbose);	/* default
to 64MB */
> +	if (io_tlb_start)
> +		free_bootmem(io_tlb_start,
> +				 PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
> +	pr_warn("Cannot allocate SWIOTLB buffer");
> +	no_iotlb_memory = true;
>  }
>  
>  /*
> @@ -405,6 +413,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device
*hwdev,
>  	unsigned long offset_slots;
>  	unsigned long max_slots;
>  
> +	if (no_iotlb_memory)
> +		panic("Can not allocate SWIOTLB buffer earlier and can't now
provide you with the DMA bounce buffer");
> +
>  	mask = dma_get_seg_boundary(hwdev);
>  
>  	tbl_dma_addr &= mask;
> -- 
> 1.7.10.4
>

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