Re: [Qemu-devel] [PATCH] target/ppc: fix CPU hotplug when radix is enabled (TCG)

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

On Fri, 2017-07-14 at 18:13 +0200, Cédric Le Goater wrote:
> But when a guest initializes radix mode, it issues a
> H_REGISTER_PROC_TBL
> to update the LPCR of all CPUs. Hot-plugged CPUs inherit from the
> same
> setting under KVM but not under TCG. So, Let's check for radix and
> update
> the default LPCR to keep new CPUs in sync.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>

Reviewed-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>

> ---
>  target/ppc/translate_init.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/target/ppc/translate_init.c
> b/target/ppc/translate_init.c
> index 8b9807665dd5..8776e9b0f8fa 100644
> --- a/target/ppc/translate_init.c
> +++ b/target/ppc/translate_init.c
> @@ -9014,8 +9014,16 @@ void cpu_ppc_set_papr(PowerPCCPU *cpu,
> PPCVirtualHypervisor *vhyp)
>          /* By default we choose legacy mode and switch to new hash
> or radix
>           * when a register process table hcall is made. So disable
> process
>           * tables and guest translation shootdown by default
> +         *
> +         * Hot-plugged CPUs inherit from the guest radix setting
> under
> +         * KVM but not under TCG. Update the default LPCR to keep
> new
> +         * CPUs in sync when radix is enabled.
>           */
> -        lpcr->default_value &= ~(LPCR_UPRT | LPCR_GTSE);
> +        if (ppc64_radix_guest(cpu)) {
> +            lpcr->default_value |= LPCR_UPRT | LPCR_GTSE;

Since we can't do radix without GTSE, I guess for now at least RADIX
implies GTSE.

> +        } else {
> +            lpcr->default_value &= ~(LPCR_UPRT | LPCR_GTSE);
> +        }
>          lpcr->default_value |= LPCR_PDEE | LPCR_HDEE | LPCR_EEE |
> LPCR_DEE |
>                                 LPCR_OEE;
>          break;