Re: [Qemu-devel] [PATCH 2/2] acpi: cleanups tcpa table generation

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 07/30/2014 07:34 AM, Michael S. Tsirkin wrote:
> Improve readability, no functional changes.

There's a subtle problem -- I am fixing this for v3.

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>   hw/i386/acpi-build.c | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 66cde2b..6ae3a9e 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1209,17 +1209,13 @@ build_hpet(GArray *table_data, GArray *linker)
>   static void
>   build_tpm_tcpa(GArray *table_data, GArray *linker)
>   {
> -    Acpi20Tcpa *tcpa;
> -    uint32_t log_area_minimum_length = TPM_LOG_AREA_MINIMUM_SIZE;
> -    uint64_t log_area_start_address;
> -    size_t len = log_area_minimum_length + sizeof(*tcpa);
> +    Acpi20Tcpa *tcpa = acpi_data_push(table_data, sizeof *tcpa);
> +    uint64_t log_area_start_address = acpi_data_len(table_data);
>
> -    log_area_start_address = table_data->len + sizeof(*tcpa);
> -
> -    tcpa = acpi_data_push(table_data, len);
> +    acpi_data_push(table_data, TPM_LOG_AREA_MINIMUM_SIZE);

This 2nd acpi_data_push manipulates table_data and the BIOS linker 
loader function further below now operates with this new table_data 
offsets etc. We have to move this acpi_data_push all the way to the end 
and then it works.

>
>       tcpa->platform_class = cpu_to_le16(TPM_TCPA_ACPI_CLASS_CLIENT);
> -    tcpa->log_area_minimum_length = cpu_to_le32(log_area_minimum_length);
> +    tcpa->log_area_minimum_length = cpu_to_le32(TPM_LOG_AREA_MINIMUM_SIZE);
>       tcpa->log_area_start_address = cpu_to_le64(log_area_start_address);
>
>       /* LASA address to be filled by Guest linker */