On Tue, 2016-10-04 at 11:07 +0200, 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 is not available.
>
> Reviewed-by: Laurent Vivier <lvivier@xxxxxxxxxx>
> Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
Thanks for sending a v3.
Reviewed-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> ---
> v3:
> - Removed unnecessary check for "plen >= 26" in cpu_has_tm()
>
> v2:
> - Reworked the check for the "ibm,pa-features" and added a comment
> - Use a dedicated variable "has_tm" instead of "i" in main()
>
> powerpc/tm.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/powerpc/tm.c b/powerpc/tm.c
> index 6ce750a..b611061 100644
> --- a/powerpc/tm.c
> +++ b/powerpc/tm.c
> @@ -10,6 +10,41 @@
> #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);
> + if (!prop) /* No features means TM is also not
> available */
> + return;
> + /* Sanity check for the property layout (first two bytes are
> header) */
> + assert(plen >= 8 && prop->data[1] == 0 && prop->data[0] <=
> plen - 2);
> +
> + /*
> + * The "Transactional Memory Category Support" flags are at
> byte
> + * offset 22 and 23 of the attribute type 0, so when adding
> the
> + * two bytes for the header, we've got to look at offset 24
> for
> + * the TM support bit.
> + */
> + if (prop->data[0] >= 24 && (prop->data[24] & 0x80) != 0)
> + *(int *)ptr += 1;
> +}
> +
> +/* 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)
> {
> @@ -101,11 +136,17 @@ struct {
>
> int main(int argc, char **argv)
> {
> - bool all;
> + bool all, has_tm;
> int i;
>
> report_prefix_push("tm");
>
> + has_tm = all_cpus_have_tm();
> + report_xfail("TM available in 'ibm,pa-features' property",
> + !has_tm, has_tm);
> + if (!has_tm)
> + return report_summary();
> +
> all = argc == 1 || !strcmp(argv[1], "all");
>
> for (i = 0; hctests[i].name != NULL; i++) {
--
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