[v2,19/25] x86: mtrr: Update MTRRs on all CPUs

When the boot CPU MTRRs are updated, perform the same update on all other
CPUs so they are kept in sync.

This avoids kernel warnings about mismatched MTRRs.

Signed-off-by: Simon Glass <sjg at chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner at br-automation.com>
---

Changes in v2:
- Rename function to mtrr_write_all()

 arch/x86/cpu/mtrr.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

Hi Simon,

On Mon, Jun 15, 2020 at 1:00 AM Simon Glass <sjg at chromium.org> wrote:
>
> When the boot CPU MTRRs are updated, perform the same update on all other
> CPUs so they are kept in sync.
>
> This avoids kernel warnings about mismatched MTRRs.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Reviewed-by: Wolfgang Wallner <wolfgang.wallner at br-automation.com>
> ---
>
> Changes in v2:
> - Rename function to mtrr_write_all()
>
>  arch/x86/cpu/mtrr.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
>
> diff --git a/arch/x86/cpu/mtrr.c b/arch/x86/cpu/mtrr.c
> index c9b4e7d06e..5c567551e5 100644
> --- a/arch/x86/cpu/mtrr.c
> +++ b/arch/x86/cpu/mtrr.c
> @@ -74,10 +74,61 @@ void mtrr_read_all(struct mtrr_info *info)
>         }
>  }
>
> +void mtrr_write_all(struct mtrr_info *info)
> +{
> +       struct mtrr_state state;
> +       int i;
> +
> +       for (i = 0; i < MTRR_COUNT; i++) {
> +               mtrr_open(&state, true);
> +               wrmsrl(MTRR_PHYS_BASE_MSR(i), info->mtrr[i].base);
> +               wrmsrl(MTRR_PHYS_MASK_MSR(i), info->mtrr[i].mask);
> +               mtrr_close(&state, true);
> +       }
> +}
> +
> +static void write_mtrrs(void *arg)
> +{
> +       struct mtrr_info *info = arg;
> +
> +       mtrr_write_all(info);
> +}
> +
> +static void read_mtrrs(void *arg)
> +{
> +       struct mtrr_info *info = arg;
> +
> +       mtrr_read_all(info);
> +}
> +
> +/**
> + * mtrr_copy_to_aps() - Copy the MTRRs from the boot CPU to other CPUs
> + *
> + * @return 0 on success, -ve on failure
> + */
> +static int mtrr_copy_to_aps(void)
> +{
> +       struct mtrr_info info;
> +       int ret;
> +
> +       ret = mp_run_on_cpus(MP_SELECT_BSP, read_mtrrs, &info);
> +       if (ret == -ENXIO)
> +               return 0;
> +       else if (ret)
> +               return log_msg_ret("bsp", ret);
> +
> +       ret = mp_run_on_cpus(MP_SELECT_APS, write_mtrrs, &info);
> +       if (ret)
> +               return log_msg_ret("bsp", ret);
> +
> +       return 0;
> +}
> +
>  int mtrr_commit(bool do_caches)
>  {
>         struct mtrr_request *req = gd->arch.mtrr_req;
>         struct mtrr_state state;
> +       int ret;
>         int i;
>
>         debug("%s: enabled=%d, count=%d\n", __func__, gd->arch.has_mtrr,
> @@ -99,6 +150,12 @@ int mtrr_commit(bool do_caches)
>         mtrr_close(&state, do_caches);
>         debug("mtrr done\n");
>
> +       if (gd->flags & GD_FLG_RELOC) {
> +               ret = mtrr_copy_to_aps();
> +               if (ret)
> +                       return log_msg_ret("copy", ret);
> +       }
> +
>         return 0;
>  }
>
> --

We need to find a place where mtrr in BSP is duplicated in AP.

Currently this is done in init_cache_f_r() but at that time SMP is not
ready yet.

Regards,
Bin