[dpdk-dev] could not l2fwd in DOM0

["Liu, Jijiang" <jijiang.liu@intel.com>]

In Linux kernel versions < 3.14 , the vstart is kernel virtual address, the API prototype below.
int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
				 unsigned int address_bits)

In Linux kernel 3.14, the pstart is kernel physical address, the API prototype below.
int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
				 unsigned int address_bits,
				 dma_addr_t *dma_handle)

,so the mm_data->block_info[i].vir_addr cannot pass to xen_create_contiguous_region() directly for Linux kernel 3.14, the pstart should be mm_data->block_info[i].pfn * PAGE_SIZE in the Dom0 Driver.

#include <linux/errno.h>
 #include <linux/vmalloc.h>
 #include <linux/mm.h>

 #include <xen/xen.h>
 #include <xen/page.h>
@@ -309,6 +310,7 @@ dom0_prepare_memsegs(struct memory_info* meminfo, struct dom0_mm_data
        uint64_t pfn, vstart, vaddr;
        uint32_t i, num_block, size;
        int idx;
+       dma_addr_t dma_handle;

        /* Allocate 2M memory once */
        num_block = meminfo->size / 2;
@@ -344,7 +346,7 @@ dom0_prepare_memsegs(struct memory_info* meminfo, struct dom0_mm_data
                 * contiguous physical addresses, its maximum size is 2M.
                 */
                if (xen_create_contiguous_region(mm_data->block_info[i].pfn * PAGE_SIZE,
-                                   DOM0_CONTIG_NUM_ORDER, 0) == 0) {
+                                   DOM0_CONTIG_NUM_ORDER, 0,
+ &dma_handle) == 0) {
                        mm_data->block_info[i].exchange_flag = 1;
                        mm_data->block_info[i].mfn =
                                pfn_to_mfn(mm_data->block_info[i].pfn);

Thanks
Frank Liu

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Samuel Monderer
Sent: Wednesday, May 07, 2014 8:44 PM
To: Liu, Jijiang
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] could not l2fwd in DOM0

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Liu, Jijiang
> Sent: Wednesday, May 07, 2014 7:36 AM
> To: dev@dpdk.org
> Subject: Re: [dpdk-dev] could not l2fwd in DOM0
> 
> Hi,
> 
> I have checked source codes of xen_create_contiguous_region function 
> in kernel 3.14, and found the dma_handle cannot be NULL.
> 
> int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
>                                  unsigned int address_bits,
>                                  dma_addr_t *dma_handle) {
>         unsigned long *in_frames = discontig_frames, out_frame;
>         unsigned long  flags;
>         int            success;
>         unsigned long vstart = (unsigned long)phys_to_virt(pstart);
>     ...
>         *dma_handle = virt_to_machine(vstart).maddr;
>         return success ? 0 : -ENOMEM;
> }
> 
> Thanks
> Frank Liu
> 

Thanks Frank,

I've changed the code as following but now the kernel module crashes.

diff --git a/lib/librte_eal/linuxapp/xen_dom0/dom0_mm_misc.c
b/lib/librte_eal/linuxapp/xen index 87fa3e6..8addc21 100644
--- a/lib/librte_eal/linuxapp/xen_dom0/dom0_mm_misc.c
+++ b/lib/librte_eal/linuxapp/xen_dom0/dom0_mm_misc.c
@@ -64,6 +64,7 @@
 #include <linux/errno.h>
 #include <linux/vmalloc.h>
 #include <linux/mm.h>

 #include <xen/xen.h>
 #include <xen/page.h>
@@ -309,6 +310,7 @@ dom0_prepare_memsegs(struct memory_info* meminfo, struct dom0_mm_data
        uint64_t pfn, vstart, vaddr;
        uint32_t i, num_block, size;
        int idx;
+       dma_addr_t dma_handle;

        /* Allocate 2M memory once */
        num_block = meminfo->size / 2;
@@ -344,7 +346,7 @@ dom0_prepare_memsegs(struct memory_info* meminfo, struct dom0_mm_data
                 * contiguous physical addresses, its maximum size is 2M.
                 */
                if (xen_create_contiguous_region(mm_data->block_info[i].vir_addr,
-                                   DOM0_CONTIG_NUM_ORDER, 0) == 0) {
+                                   DOM0_CONTIG_NUM_ORDER, 0,
+ &dma_handle) == 0) {
                        mm_data->block_info[i].exchange_flag = 1;
                        mm_data->block_info[i].mfn =
                                pfn_to_mfn(mm_data->block_info[i].pfn);

Samuel

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Samuel Monderer
> Sent: Wednesday, April 30, 2014 1:54 AM
> To: dev@dpdk.org<mailto:dev@dpdk.org>
> Cc: Shimon Zadok
> Subject: [dpdk-dev] could not l2fwd in DOM0
> 
> Hi,
> 
> First I've encountered a compiling problem when compiling for DOM0 due 
> to prototype change of the function xen_create_contiguous_region I 
> made the following changes:
> 
> diff --git a/lib/librte_eal/linuxapp/xen_dom0/dom0_mm_misc.c
> b/lib/librte_eal/linuxapp/xen index 87fa3e6..8addc21 100644
> --- a/lib/librte_eal/linuxapp/xen_dom0/dom0_mm_misc.c
> +++ b/lib/librte_eal/linuxapp/xen_dom0/dom0_mm_misc.c
> @@ -64,6 +64,7 @@
>  #include <linux/errno.h>
>  #include <linux/vmalloc.h>
>  #include <linux/mm.h>
> +//#include <linux/types.h>
> 
>  #include <xen/xen.h>
>  #include <xen/page.h>
> @@ -309,6 +310,7 @@ dom0_prepare_memsegs(struct memory_info* meminfo, 
> struct dom0_mm_data
>         uint64_t pfn, vstart, vaddr;
>         uint32_t i, num_block, size;
>         int idx;
> +       dma_addr_t *dma_handle = NULL;
> 
>         /* Allocate 2M memory once */
>         num_block = meminfo->size / 2; @@ -344,7 +346,7 @@ 
> dom0_prepare_memsegs(struct memory_info* meminfo, struct dom0_mm_data
>                  * contiguous physical addresses, its maximum size is 2M.
>                  */
>                 if (xen_create_contiguous_region(mm_data->block_info[i].vir_addr,
> -                                   DOM0_CONTIG_NUM_ORDER, 0) == 0) {
> +                                   DOM0_CONTIG_NUM_ORDER, 0,
> + dma_handle) == 0) {
>                         mm_data->block_info[i].exchange_flag = 1;
>                         mm_data->block_info[i].mfn =
>                                 
> pfn_to_mfn(mm_data->block_info[i].pfn);
> 
> After that I tried to run l2fwd example and got a segmentation fault
> 
> root@Smart:~/samuelm/dpdk/dpdk# modprobe uio 
> root@Smart:~/samuelm/dpdk/dpdk# insmod ./x86_64-default-linuxapp- 
> gcc/kmod/igb_uio.ko root@Smart:~/samuelm/dpdk/dpdk# insmod 
> ./x86_64-default-linuxapp- gcc/kmod/rte_dom0_mm.ko 
> root@Smart:~/samuelm/dpdk/dpdk# cd examples/l2fwd/build/ 
> root@Smart:~/samuelm/dpdk/dpdk/examples/l2fwd/build# echo 2048 > 
> /sys/kernel/mm/dom0-mm/memsize-mB/memsize
> root@Smart:~/samuelm/dpdk/dpdk/examples/l2fwd/build# ./l2fwd -c 3 -n 4
> --xen-dom0 -- -q 1 -p 3
> EAL: Detected lcore 0 as core 0 on socket 0
> EAL: Detected lcore 1 as core 0 on socket 0
> EAL: Setting up memory...
> Segmentation fault
> root@Smart:~/samuelm/dpdk/dpdk/examples/l2fwd/build#
> 
> Has anyone already encountered this problem?
> 
> Samuelm