Re: [Xen-devel] could not l2fwd in DOM0

[Samuel Monderer <SMonderer@xxxxxxxxxxxxxxx>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@xxxxxxxx] On Behalf Of Liu, Jijiang
> Sent: Wednesday, May 07, 2014 7:36 AM
> To: dev@xxxxxxxx
> 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@xxxxxxxx] On Behalf Of Samuel Monderer
> Sent: Wednesday, April 30, 2014 1:54 AM
> To: dev@xxxxxxxx<mailto:dev@xxxxxxxx>
> 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


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