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Re: [Qemu-ppc] [PATCH for-2.10 2/2] target/ppc: Add stub implementation
From: |
Cédric Le Goater |
Subject: |
Re: [Qemu-ppc] [PATCH for-2.10 2/2] target/ppc: Add stub implementation of the PSSCR |
Date: |
Tue, 8 Aug 2017 11:19:58 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 |
On 08/08/2017 08:08 AM, David Gibson wrote:
> The PSSCR register added in POWER9 controls certain power saving mode
> behaviours. Mostly, it's not relevant to TCG, however because qemu
> doesn't know about it yet, it doesn't synchronize the state with KVM,
> and thus it doesn't get migrated.
>
> To fix that, this adds a minimal stub implementation of the register.
> This isn't complete, even to the extent that an implementation is
> possible in TCG, just enough to get migration working. We need to
> come back later and at least properly filter the various fields in the
> register based on privilege level.
yes a lot of the fields are only accessible to the hypervisor, and the
hypervisor also uses a different SPR number to access the PSSCR bits.
Reviewed-by: Cédric Le Goater <address@hidden>
C.
>
> Signed-off-by: David Gibson <address@hidden>
> ---
> target/ppc/cpu.h | 1 +
> target/ppc/translate_init.c | 5 +++++
> 2 files changed, 6 insertions(+)
>
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index f6e5413fad..46d3dd88f6 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -1771,6 +1771,7 @@ void ppc_compat_add_property(Object *obj, const char
> *name,
> #define SPR_IC (0x350)
> #define SPR_VTB (0x351)
> #define SPR_MMCRC (0x353)
> +#define SPR_PSSCR (0x357)
> #define SPR_440_INV0 (0x370)
> #define SPR_440_INV1 (0x371)
> #define SPR_440_INV2 (0x372)
> diff --git a/target/ppc/translate_init.c b/target/ppc/translate_init.c
> index 94800cd29d..8fb407ed73 100644
> --- a/target/ppc/translate_init.c
> +++ b/target/ppc/translate_init.c
> @@ -8846,6 +8846,11 @@ static void init_proc_POWER9(CPUPPCState *env)
> spr_read_generic, spr_write_generic,
> KVM_REG_PPC_TIDR, 0);
>
> + /* FIXME: Filter fields properly based on privilege level */
> + spr_register_kvm_hv(env, SPR_PSSCR, "PSSCR", NULL, NULL, NULL, NULL,
> + spr_read_generic, spr_write_generic,
> + KVM_REG_PPC_PSSCR, 0);
> +
> /* env variables */
> #if !defined(CONFIG_USER_ONLY)
> env->slb_nr = 32;
>