[for-2.13,05/10] spapr: Move PAPR mode register initialization to spapr code

cpu_ppc_set_papr() has code to make sure the LPCR and AMOR (hypervisor
privileged registers) have values which will make TCG behave correctly for
paravirtualized guests, where we don't emulate the cpu when in hypervisor
mode.

It does this by mangling the default values of the SPRs, so that they will
be set correctly at reset time.  Manipulating usually-static parameters of
the cpu model like this is kind of ugly, especially since the values used
really have more to do with the platform than the cpu.

The spapr code already has places for PAPR specific initializations of
register state, so move the handling of LPCR and AMOR to there.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr_cpu_core.c     | 36 +++++++++++++++++++++++++++++++++++-
 target/ppc/translate_init.c | 39 ---------------------------------------
 2 files changed, 35 insertions(+), 40 deletions(-)

On Tue, 17 Apr 2018 17:17:17 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> cpu_ppc_set_papr() has code to make sure the LPCR and AMOR (hypervisor
> privileged registers) have values which will make TCG behave correctly for
> paravirtualized guests, where we don't emulate the cpu when in hypervisor
> mode.
> 
> It does this by mangling the default values of the SPRs, so that they will
> be set correctly at reset time.  Manipulating usually-static parameters of
> the cpu model like this is kind of ugly, especially since the values used
> really have more to do with the platform than the cpu.
> 
> The spapr code already has places for PAPR specific initializations of
> register state, so move the handling of LPCR and AMOR to there.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  hw/ppc/spapr_cpu_core.c     | 36 +++++++++++++++++++++++++++++++++++-
>  target/ppc/translate_init.c | 39 ---------------------------------------
>  2 files changed, 35 insertions(+), 40 deletions(-)
> 
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 2aab6ccd15..9080664ec1 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -28,6 +28,7 @@ static void spapr_cpu_reset(void *opaque)
>      CPUState *cs = CPU(cpu);
>      CPUPPCState *env = &cpu->env;
>      PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
> +    target_ulong lpcr;
>  
>      cpu_reset(cs);
>  
> @@ -41,13 +42,46 @@ static void spapr_cpu_reset(void *opaque)
>       * using an RTAS call */
>      cs->halted = 1;
>  
> +    lpcr = env->spr[SPR_LPCR];
> +
> +    /* Set emulated LPCR to not send interrupts to hypervisor. Note that
> +     * under KVM, the actual HW LPCR will be set differently by KVM itself,
> +     * the settings below ensure proper operations with TCG in absence of
> +     * a real hypervisor.
> +     *
> +     * Clearing VPM0 will also cause us to use RMOR in mmu-hash64.c for
> +     * real mode accesses, which thankfully defaults to 0 and isn't
> +     * accessible in guest mode.
> +     */
> +    lpcr &= ~(LPCR_VPM0 | LPCR_VPM1 | LPCR_ISL | LPCR_KBV);
> +    lpcr |= LPCR_LPES0 | LPCR_LPES1;
> +
> +    /* Set RMLS to the max (ie, 16G) */
> +    lpcr &= ~LPCR_RMLS;
> +    lpcr |= 1ull << LPCR_RMLS_SHIFT;
> +
> +    /* Only enable Power-saving mode Exit Cause exceptions on the boot
> +     * CPU. The RTAS command start-cpu will enable them on secondaries.
> +     */
> +    if (cs == first_cpu) {
> +        lpcr |= pcc->lpcr_pm;
> +    }
> +
>      /* Disable Power-saving mode Exit Cause exceptions for the CPU.
>       * This can cause issues when rebooting the guest if a secondary
>       * is awaken */
>      if (cs != first_cpu) {
> -        env->spr[SPR_LPCR] &= ~pcc->lpcr_pm;
> +        lpcr &= ~pcc->lpcr_pm;
>      }
>  

Maybe fold these into a single if-else with a consolidated comment ?

    /* Only enable Power-saving mode Exit Cause exceptions on the boot
     * CPU and disable it for secondaries because it is known to cause
     * issues if a secondary is awaken too early when rebooting the guest.
     * The RTAS command start-cpu will enable exceptions on secondaries.
     */
    if (cs == first_cpu) {
        lpcr |= pcc->lpcr_pm;
    } else {
        lpcr &= ~pcc->lpcr_pm;
    }

Anyway, the patch looks good and makes cpu_ppc_set_papr() a lot clearer.

Reviewed-by: Greg Kurz <groug@kaod.org>

> +    env->spr[SPR_LPCR] = lpcr;
> +
> +    /* Set a full AMOR so guest can use the AMR as it sees fit */
> +    env->spr[SPR_AMOR] = 0xffffffffffffffffull;
> +
> +    /* Update some env bits based on new LPCR value */
> +    ppc_hash64_update_rmls(cpu);
> +    ppc_hash64_update_vrma(cpu);
>  }
>  
>  static void spapr_cpu_destroy(PowerPCCPU *cpu)
> diff --git a/target/ppc/translate_init.c b/target/ppc/translate_init.c
> index 14f346f441..5e89901149 100644
> --- a/target/ppc/translate_init.c
> +++ b/target/ppc/translate_init.c
> @@ -8866,11 +8866,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void *data)
>  #if !defined(CONFIG_USER_ONLY)
>  void cpu_ppc_set_papr(PowerPCCPU *cpu, PPCVirtualHypervisor *vhyp)
>  {
> -    PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
>      CPUPPCState *env = &cpu->env;
> -    ppc_spr_t *lpcr = &env->spr_cb[SPR_LPCR];
> -    ppc_spr_t *amor = &env->spr_cb[SPR_AMOR];
> -    CPUState *cs = CPU(cpu);
>  
>      cpu->vhyp = vhyp;
>  
> @@ -8881,41 +8877,6 @@ void cpu_ppc_set_papr(PowerPCCPU *cpu, PPCVirtualHypervisor *vhyp)
>       */
>      env->msr_mask &= ~((1ull << MSR_EP) | MSR_HVB);
>  
> -    /* Set emulated LPCR to not send interrupts to hypervisor. Note that
> -     * under KVM, the actual HW LPCR will be set differently by KVM itself,
> -     * the settings below ensure proper operations with TCG in absence of
> -     * a real hypervisor.
> -     *
> -     * Clearing VPM0 will also cause us to use RMOR in mmu-hash64.c for
> -     * real mode accesses, which thankfully defaults to 0 and isn't
> -     * accessible in guest mode.
> -     */
> -    lpcr->default_value &= ~(LPCR_VPM0 | LPCR_VPM1 | LPCR_ISL | LPCR_KBV);
> -    lpcr->default_value |= LPCR_LPES0 | LPCR_LPES1;
> -
> -    /* Set RMLS to the max (ie, 16G) */
> -    lpcr->default_value &= ~LPCR_RMLS;
> -    lpcr->default_value |= 1ull << LPCR_RMLS_SHIFT;
> -
> -    /* Only enable Power-saving mode Exit Cause exceptions on the boot
> -     * CPU. The RTAS command start-cpu will enable them on secondaries.
> -     */
> -    if (cs == first_cpu) {
> -        lpcr->default_value |= pcc->lpcr_pm;
> -    }
> -
> -    /* We should be followed by a CPU reset but update the active value
> -     * just in case...
> -     */
> -    env->spr[SPR_LPCR] = lpcr->default_value;
> -
> -    /* Set a full AMOR so guest can use the AMR as it sees fit */
> -    env->spr[SPR_AMOR] = amor->default_value = 0xffffffffffffffffull;
> -
> -    /* Update some env bits based on new LPCR value */
> -    ppc_hash64_update_rmls(cpu);
> -    ppc_hash64_update_vrma(cpu);
> -
>      /* Tell KVM that we're in PAPR mode */
>      if (kvm_enabled()) {
>          kvmppc_set_papr(cpu);