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

[Alex Hung]

On 02/20/2013 09:15 PM, Colin King 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[] = {
>
Acked-by: Alex Hung <alex.hung at canonical.com>