[PATCH] acpi: mcfg: move PCI mmap and munmap to compare_config_space

[Keng-Yu Lin]

On Wed, Feb 20, 2013 at 9:15 PM, Colin King <colin.king at canonical.com> wrote:
> From: Colin Ian King <colin.king at canonical.com>
>
> Move the memory mapping and unmapping to compare_config_space
> and add error returns to compare_config_space.  This works around
> a bug we found in a Xen dom0 where the fork/exec trips a bug
> where the kernel reports:
>
> fwts:2737 map pfn expected mapping type write-back for [mem 0xe0000000-0xe0000fff], got uncached-minus
>
> ..the workaround for the moment is to do the mmap, read the data
> and then a munmap before we do a fork/exec.   This tidies the code anyhow
> as we keep the mapping for a minimal amount of time.
>
> The kernel bug may be related to commit 8eaffa67b43e99ae581622c5133e20b0f48bcef1
>
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
>  src/acpi/mcfg/mcfg.c | 39 ++++++++++++++++++++-------------------
>  1 file changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/src/acpi/mcfg/mcfg.c b/src/acpi/mcfg/mcfg.c
> index 29538db..0359585 100644
> --- a/src/acpi/mcfg/mcfg.c
> +++ b/src/acpi/mcfg/mcfg.c
> @@ -32,19 +32,29 @@
>  static fwts_list *memory_map_list;
>  static fwts_acpi_table_info *mcfg_table;
>
> -static void compare_config_space(
> +static int compare_config_space(
>         fwts_framework *fw,
>         const uint16_t segment,
>         const uint32_t device,
> -       const uint8_t *space)
> +       fwts_acpi_mcfg_configuration *config)
>  {
>         fwts_list *lspci_output;
>         fwts_list_link *item;
>         int status;
> +       uint8_t *space;
> +       size_t page_size;
>
>         char command[PATH_MAX];
>         char compare_line[50];
>
> +       page_size = fwts_page_size();
> +
> +       /* Sanity check on first config */
> +       if ((space = fwts_mmap(config->base_address, page_size)) == FWTS_MAP_FAILED) {
> +               fwts_log_error(fw, "Cannot mmap table at 0x%" PRIx64 ".", config->base_address);
> +               return FWTS_ERROR;
> +       }
> +
>         snprintf(compare_line, sizeof(compare_line),
>                 "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
>                 space[0],  space[1],  space[2],  space[3],
> @@ -52,19 +62,21 @@ static void compare_config_space(
>                 space[8],  space[9],  space[10], space[11],
>                 space[12], space[13], space[14], space[15]);
>
> +       (void)fwts_munmap(space, page_size);
> +
>         snprintf(command, sizeof(command), "%s -vxxx -s %" PRIu16 ":%" PRIu32,
>                 fw->lspci, segment, device);
>
>         if (fwts_pipe_exec(command, &lspci_output, &status) != FWTS_OK) {
>                 fwts_log_warning(fw, "Could not execute %s", command);
> -               return;
> +               return FWTS_ERROR;
>         }
>
>         if (lspci_output == NULL) {
>                 fwts_log_warning(fw,
>                         "Failed to get lspci info for %" PRIu16 ":%" PRIu32,
>                         segment, device);
> -               return;
> +               return FWTS_ERROR;
>         }
>
>         fwts_list_foreach(item, lspci_output) {
> @@ -84,11 +96,13 @@ static void compare_config_space(
>                                 fwts_passed(fw, "PCI config space verified.");
>
>                         fwts_text_list_free(lspci_output);
> -                       return;
> +                       return FWTS_OK;
>                 }
>         }
>         fwts_text_list_free(lspci_output);
>         fwts_log_warning(fw, "Possible PCI space config space defect?");
> +
> +       return FWTS_ERROR;
>  }
>
>  static int mcfg_init(fwts_framework *fw)
> @@ -228,7 +242,6 @@ static int mcfg_test1(fwts_framework *fw)
>         if (!failed)
>                 fwts_passed(fw, "MCFG mmio config space is reserved in memory map table.");
>
> -
>         return FWTS_OK;
>  }
>
> @@ -239,10 +252,6 @@ static int mcfg_test2(fwts_framework *fw)
>  {
>         fwts_acpi_table_mcfg *mcfg = (fwts_acpi_table_mcfg *)mcfg_table->data;
>         fwts_acpi_mcfg_configuration *config;
> -       uint8_t *mapped_table_page;
> -       size_t page_size;
> -
> -       page_size = fwts_page_size();
>
>         if (mcfg == NULL) {
>                 fwts_failed(fw, LOG_LEVEL_HIGH, "MCFGInvalidTable",
> @@ -260,15 +269,7 @@ static int mcfg_test2(fwts_framework *fw)
>
>         config = &mcfg->configuration[0];
>
> -       /* Sanity check on first config */
> -       if ((mapped_table_page = fwts_mmap(config->base_address, page_size)) == FWTS_MAP_FAILED) {
> -               fwts_log_error(fw, "Cannot mmap table at 0x%" PRIx64 ".", config->base_address);
> -               return FWTS_ERROR;
> -       }
> -       compare_config_space(fw, config->pci_segment_group_number, 0, mapped_table_page);
> -       fwts_munmap(mapped_table_page, page_size);
> -
> -       return FWTS_OK;
> +       return compare_config_space(fw, config->pci_segment_group_number, 0, config);
>  }
>
>  static fwts_framework_minor_test mcfg_tests[] = {
> --
> 1.8.1.2
>
Acked-by: Keng-Yu Lin <kengyu at canonical.com>