[v5,2/2] eal: use base address hint to reserve space for mem config

  Currently, mem config will be mapped without using the virtual
area reservation infrastructure, which means it will be mapped
at an arbitrary location. This may cause failures to map the
shared config in secondary process due to things like PCI
whitelist arguments allocating memory in a space where the
primary has allocated the shared mem config.

Fix this by using virtual area reservation to reserve space for
the mem config, thereby avoiding the problem and reserving the
shared config (hopefully) far away from any normal memory
allocations.

Cc: stable@dpdk.org

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---

Notes:
    v4:
    - Fix mem config length to always be page-aligned
    
    v3:
    - Fix alignment issues with base address
    
    v2:
    - Fix issue with unneeded ADDR_IS_HINT flag that broke things
      on 32-bit builds

 lib/librte_eal/freebsd/eal/eal.c | 28 +++++++++++++++++++++------
 lib/librte_eal/linux/eal/eal.c   | 33 +++++++++++++++++++++++---------
 2 files changed, 46 insertions(+), 15 deletions(-)
  

On Thu, Oct 24, 2019 at 2:37 PM Anatoly Burakov
<anatoly.burakov@intel.com> wrote:
>
> Currently, mem config will be mapped without using the virtual
> area reservation infrastructure, which means it will be mapped
> at an arbitrary location. This may cause failures to map the
> shared config in secondary process due to things like PCI
> whitelist arguments allocating memory in a space where the
> primary has allocated the shared mem config.
>
> Fix this by using virtual area reservation to reserve space for
> the mem config, thereby avoiding the problem and reserving the
> shared config (hopefully) far away from any normal memory
> allocations.
>
> Cc: stable@dpdk.org
>
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>
> Notes:
>     v4:
>     - Fix mem config length to always be page-aligned
>
>     v3:
>     - Fix alignment issues with base address
>
>     v2:
>     - Fix issue with unneeded ADDR_IS_HINT flag that broke things
>       on 32-bit builds
>
>  lib/librte_eal/freebsd/eal/eal.c | 28 +++++++++++++++++++++------
>  lib/librte_eal/linux/eal/eal.c   | 33 +++++++++++++++++++++++---------
>  2 files changed, 46 insertions(+), 15 deletions(-)
>
> diff --git a/lib/librte_eal/freebsd/eal/eal.c b/lib/librte_eal/freebsd/eal/eal.c
> index f86e9aa318..5b869b895a 100644
> --- a/lib/librte_eal/freebsd/eal/eal.c
> +++ b/lib/librte_eal/freebsd/eal/eal.c
> @@ -218,7 +218,10 @@ eal_parse_sysfs_value(const char *filename, unsigned long *val)
>  static int
>  rte_eal_config_create(void)
>  {
> -       void *rte_mem_cfg_addr;
> +       size_t page_sz = sysconf(_SC_PAGE_SIZE);
> +       size_t cfg_len = sizeof(*rte_config.mem_config);
> +       size_t cfg_len_aligned = RTE_ALIGN(cfg_len, page_sz);
> +       void *rte_mem_cfg_addr, *mapped_mem_cfg_addr;
>         int retval;
>
>         const char *pathname = eal_runtime_config_path();

Updated existing call to sysconf with page_sz variable.

       if (internal_config.base_virtaddr != 0)
               rte_mem_cfg_addr = (void *)
                       RTE_ALIGN_FLOOR(internal_config.base_virtaddr -
-                      sizeof(struct rte_mem_config), sysconf(_SC_PAGE_SIZE));
+                      sizeof(struct rte_mem_config), page_sz);
       else
               rte_mem_cfg_addr = NULL;


> @@ -235,7 +238,7 @@ rte_eal_config_create(void)
>                 }
>         }
>
> -       retval = ftruncate(mem_cfg_fd, sizeof(*rte_config.mem_config));
> +       retval = ftruncate(mem_cfg_fd, cfg_len);
>         if (retval < 0){
>                 close(mem_cfg_fd);
>                 mem_cfg_fd = -1;
> @@ -253,15 +256,28 @@ rte_eal_config_create(void)
>                 return -1;
>         }
>
> -       rte_mem_cfg_addr = mmap(NULL, sizeof(*rte_config.mem_config),
> -                               PROT_READ | PROT_WRITE, MAP_SHARED, mem_cfg_fd, 0);
> -
> -       if (rte_mem_cfg_addr == MAP_FAILED){
> +       /* reserve space for config */
> +       rte_mem_cfg_addr = eal_get_virtual_area(NULL, &cfg_len_aligned, page_sz,
> +                       0, 0);

Fixed conflict with base-virtaddr patches.

> +       if (rte_mem_cfg_addr == NULL) {
>                 RTE_LOG(ERR, EAL, "Cannot mmap memory for rte_config\n");
>                 close(mem_cfg_fd);
>                 mem_cfg_fd = -1;
>                 return -1;
>         }

Applied, thanks.


--
David Marchand