Power9/10 CPUs have PVR[51] set in small-core mode and clear in big-core
mode. This is used by skiboot firmware.

PVR is not hypervisor-privileged but it is not so important that spapr
to implement this because it's generally masked out of PVR matching code
in kernels, and only used by firmware.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 hw/ppc/pnv_core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
index 16d40392db..a96ec4e2b9 100644
--- a/hw/ppc/pnv_core.c
+++ b/hw/ppc/pnv_core.c
@@ -58,6 +58,10 @@ static void pnv_core_cpu_reset(PnvCore *pc, PowerPCCPU *cpu)
     env->nip = 0x10;
     env->msr |= MSR_HVB; /* Hypervisor mode */
     env->spr[SPR_HRMOR] = pc->hrmor;
+    if (pc->big_core) {
+        /* Clear "small core" bit on Power9/10 (this is set in default PVR) */
+        env->spr[SPR_PVR] &= ~PPC_BIT(51);
+    }
     hreg_compute_hflags(env);
     ppc_maybe_interrupt(env);
 
-- 
2.45.1

On 7/12/24 14:02, Nicholas Piggin wrote:
> Power9/10 CPUs have PVR[51] set in small-core mode and clear in big-core
> mode. This is used by skiboot firmware.
> 
> PVR is not hypervisor-privileged but it is not so important that spapr
> to implement this because it's generally masked out of PVR matching code
> in kernels, and only used by firmware.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.


> ---
>   hw/ppc/pnv_core.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
> index 16d40392db..a96ec4e2b9 100644
> --- a/hw/ppc/pnv_core.c
> +++ b/hw/ppc/pnv_core.c
> @@ -58,6 +58,10 @@ static void pnv_core_cpu_reset(PnvCore *pc, PowerPCCPU *cpu)
>       env->nip = 0x10;
>       env->msr |= MSR_HVB; /* Hypervisor mode */
>       env->spr[SPR_HRMOR] = pc->hrmor;
> +    if (pc->big_core) {
> +        /* Clear "small core" bit on Power9/10 (this is set in default PVR) */
> +        env->spr[SPR_PVR] &= ~PPC_BIT(51);
> +    }
>       hreg_compute_hflags(env);
>       ppc_maybe_interrupt(env);
>