On 28/09/2016 12:18, Thomas Huth wrote:
> Transactional memory is currently only supported on KVM-HV, and
> not yet on KVM-PR. So it's better to check the device tree first
> and fail gracefully if it's not available.
>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
> ---
> powerpc/tm.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/powerpc/tm.c b/powerpc/tm.c
> index 6ce750a..83d9d3d 100644
> --- a/powerpc/tm.c
> +++ b/powerpc/tm.c
> @@ -10,6 +10,32 @@
> #include <asm/processor.h>
> #include <asm/handlers.h>
> #include <asm/smp.h>
> +#include <asm/setup.h>
> +#include <devicetree.h>
> +
> +/* Check "ibm,pa-features" property of a CPU node for the TM flag */
> +static void cpu_has_tm(int fdtnode, u32 regval __unused, void *ptr)
> +{
> + const struct fdt_property *prop;
> + int plen;
> +
> + prop = fdt_get_property(dt_fdt(), fdtnode, "ibm,pa-features", &plen);
> + assert(prop != NULL);
> +
> + if (plen >= 26 && prop->data[1] == 0 && (prop->data[24] & 0x80) != 0)
> + *(int *)ptr += 1;
Perhaps some comments can help here:
why do you check plen >= 26 and not >= 25?
why do you check prop->data[1]?
why don't you check prop->data[23] for the size of the attribute?
> +}
> +
> +/* Check whether all CPU nodes have the TM flag */
> +static bool all_cpus_have_tm(void)
> +{
> + int ret;
> + int available = 0;
> +
> + ret = dt_for_each_cpu_node(cpu_has_tm, &available);
> +
> + return ret == 0 && available == nr_cpus;
> +}
>
> static int h_cede(void)
> {
> @@ -106,6 +132,11 @@ int main(int argc, char **argv)
>
> report_prefix_push("tm");
>
> + i = all_cpus_have_tm();
> + report_xfail("TM available in 'ibm,pa-features' property", !i, i);
> + if (!i)
> + return report_summary();
> +
perhaps you can use a more explicit variable name for "i"?
> all = argc == 1 || !strcmp(argv[1], "all");
>
> for (i = 0; hctests[i].name != NULL; i++) {
>
Thanks,
Laurent
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