This patch adds tcg accessors for 2 SPRs which were missing on P10:

- the TBU40 register is used to write the upper 40 bits of the
timebase register. It is used by kvm to update the timebase when
entering/exiting the guest on P9 and above. The missing definition was
causing erratic decrementer interrupts in a pseries/kvm guest running
in a powernv10/tcg host, typically resulting in hangs.

- the missing DPDES SPR was found through code inspection. It exists
unchanged on P10.

Both existed on previous versions of the processor and a bit of git
archaeology hints that they were added while the P10 model was already
being worked on so they may have simply fallen through the cracks.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
---
 target/ppc/cpu_init.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 073fd10168..2e9a3ded54 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -6457,6 +6457,7 @@ static void init_proc_POWER10(CPUPPCState *env)
     register_power5p_common_sprs(env);
     register_power5p_lpar_sprs(env);
     register_power5p_ear_sprs(env);
+    register_power5p_tb_sprs(env);
     register_power6_common_sprs(env);
     register_power6_dbg_sprs(env);
     register_power8_tce_address_control_sprs(env);
@@ -6467,6 +6468,7 @@ static void init_proc_POWER10(CPUPPCState *env)
     register_power8_pmu_user_sprs(env);
     register_power8_tm_sprs(env);
     register_power8_pspb_sprs(env);
+    register_power8_dpdes_sprs(env);
     register_vtb_sprs(env);
     register_power8_ic_sprs(env);
     register_power8_book4_sprs(env);
-- 
2.35.1

Queued in gitlab.com/danielhb/qemu/tree/ppc-next. Thanks,


Daniel



On 4/11/22 09:59, Frederic Barrat wrote:
> This patch adds tcg accessors for 2 SPRs which were missing on P10:
> 
> - the TBU40 register is used to write the upper 40 bits of the
> timebase register. It is used by kvm to update the timebase when
> entering/exiting the guest on P9 and above. The missing definition was
> causing erratic decrementer interrupts in a pseries/kvm guest running
> in a powernv10/tcg host, typically resulting in hangs.
> 
> - the missing DPDES SPR was found through code inspection. It exists
> unchanged on P10.
> 
> Both existed on previous versions of the processor and a bit of git
> archaeology hints that they were added while the P10 model was already
> being worked on so they may have simply fallen through the cracks.
> 
> Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
> ---
>   target/ppc/cpu_init.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
> index 073fd10168..2e9a3ded54 100644
> --- a/target/ppc/cpu_init.c
> +++ b/target/ppc/cpu_init.c
> @@ -6457,6 +6457,7 @@ static void init_proc_POWER10(CPUPPCState *env)
>       register_power5p_common_sprs(env);
>       register_power5p_lpar_sprs(env);
>       register_power5p_ear_sprs(env);
> +    register_power5p_tb_sprs(env);
>       register_power6_common_sprs(env);
>       register_power6_dbg_sprs(env);
>       register_power8_tce_address_control_sprs(env);
> @@ -6467,6 +6468,7 @@ static void init_proc_POWER10(CPUPPCState *env)
>       register_power8_pmu_user_sprs(env);
>       register_power8_tm_sprs(env);
>       register_power8_pspb_sprs(env);
> +    register_power8_dpdes_sprs(env);
>       register_vtb_sprs(env);
>       register_power8_ic_sprs(env);
>       register_power8_book4_sprs(env);

Frederic Barrat <fbarrat@linux.ibm.com> writes:

> This patch adds tcg accessors for 2 SPRs which were missing on P10:
>
> - the TBU40 register is used to write the upper 40 bits of the
> timebase register. It is used by kvm to update the timebase when
> entering/exiting the guest on P9 and above. The missing definition was
> causing erratic decrementer interrupts in a pseries/kvm guest running
> in a powernv10/tcg host, typically resulting in hangs.
>
> - the missing DPDES SPR was found through code inspection. It exists
> unchanged on P10.
>
> Both existed on previous versions of the processor and a bit of git
> archaeology hints that they were added while the P10 model was already
> being worked on so they may have simply fallen through the cracks.
>
> Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>

Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>

> ---
>  target/ppc/cpu_init.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
> index 073fd10168..2e9a3ded54 100644
> --- a/target/ppc/cpu_init.c
> +++ b/target/ppc/cpu_init.c
> @@ -6457,6 +6457,7 @@ static void init_proc_POWER10(CPUPPCState *env)
>      register_power5p_common_sprs(env);
>      register_power5p_lpar_sprs(env);
>      register_power5p_ear_sprs(env);
> +    register_power5p_tb_sprs(env);
>      register_power6_common_sprs(env);
>      register_power6_dbg_sprs(env);
>      register_power8_tce_address_control_sprs(env);
> @@ -6467,6 +6468,7 @@ static void init_proc_POWER10(CPUPPCState *env)
>      register_power8_pmu_user_sprs(env);
>      register_power8_tm_sprs(env);
>      register_power8_pspb_sprs(env);
> +    register_power8_dpdes_sprs(env);
>      register_vtb_sprs(env);
>      register_power8_ic_sprs(env);
>      register_power8_book4_sprs(env);