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Re: [Qemu-devel] [PATCH 06/17] ppc: Create cpu_ppc_set_papr() helper
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH 06/17] ppc: Create cpu_ppc_set_papr() helper |
Date: |
Fri, 18 Mar 2016 09:03:46 +1100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Thu, Mar 17, 2016 at 01:33:31PM +0100, Cédric Le Goater wrote:
> On 03/17/2016 03:34 AM, David Gibson wrote:
> > On Mon, Mar 14, 2016 at 05:56:29PM +0100, Cédric Le Goater wrote:
> >> From: Benjamin Herrenschmidt <address@hidden>
> >>
> >> And move the code adjusting the MSR mask and calling kvmppc_set_papr()
> >> to it. This allows us to add a few more things such as disabling setting
> >> of MSR:HV and appropriate LPCR bits which will be used when fixing
> >> the exception model.
> >>
> >> Signed-off-by: Benjamin Herrenschmidt <address@hidden>
> >> Reviewed-by: David Gibson <address@hidden>
> >
> > I'm a little nervous about applying this before 2.6. This affects the
> > value of the LPCR which is used to control exception behaviour in some
> > cases. I'm pretty sure the current behaviour is wrong, but we do know
> > it doesn't break horribly for existing machines, which we'd have to
> > retest with the new behaviour.
>
> Yes. I agree.
>
> > I'm certainly willing to hear a case for this if it makes other
> > patches in the series significantly easier though.
>
> I think we should split this patch in two. Put the cpu_ppc_set_papr() helper
> and the MSR change in the first one and keep the LPCR changes for the second.
> The latter belong to another set of fixes related the exception
> models.
Yes, I think that makes sense.
>
> C.
>
> >> ---
> >> hw/ppc/spapr.c | 11 ++---------
> >> target-ppc/cpu.h | 1 +
> >> target-ppc/translate_init.c | 37 ++++++++++++++++++++++++++++++++++++-
> >> 3 files changed, 39 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> >> index 43708a2a9086..9c01872ce4d3 100644
> >> --- a/hw/ppc/spapr.c
> >> +++ b/hw/ppc/spapr.c
> >> @@ -1612,15 +1612,8 @@ static void spapr_cpu_init(sPAPRMachineState
> >> *spapr, PowerPCCPU *cpu,
> >> /* Set time-base frequency to 512 MHz */
> >> cpu_ppc_tb_init(env, TIMEBASE_FREQ);
> >>
> >> - /* PAPR always has exception vectors in RAM not ROM. To ensure this,
> >> - * MSR[IP] should never be set.
> >> - */
> >> - env->msr_mask &= ~(1 << 6);
> >> -
> >> - /* Tell KVM that we're in PAPR mode */
> >> - if (kvm_enabled()) {
> >> - kvmppc_set_papr(cpu);
> >> - }
> >> + /* Enable PAPR mode in TCG or KVM */
> >> + cpu_ppc_set_papr(cpu);
> >>
> >> if (cpu->max_compat) {
> >> Error *local_err = NULL;
> >> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
> >> index 9ce301f18922..a7da0d3e95a9 100644
> >> --- a/target-ppc/cpu.h
> >> +++ b/target-ppc/cpu.h
> >> @@ -1268,6 +1268,7 @@ void store_booke_tcr (CPUPPCState *env, target_ulong
> >> val);
> >> void store_booke_tsr (CPUPPCState *env, target_ulong val);
> >> void ppc_tlb_invalidate_all (CPUPPCState *env);
> >> void ppc_tlb_invalidate_one (CPUPPCState *env, target_ulong addr);
> >> +void cpu_ppc_set_papr(PowerPCCPU *cpu);
> >> #endif
> >> #endif
> >>
> >> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> >> index 46dabe58783a..093ef036320d 100644
> >> --- a/target-ppc/translate_init.c
> >> +++ b/target-ppc/translate_init.c
> >> @@ -8496,8 +8496,43 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
> >> pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_lpcr;
> >> pcc->threads_per_core = 8;
> >> }
> >> -#endif /* defined (TARGET_PPC64) */
> >>
> >> +#if !defined(CONFIG_USER_ONLY)
> >> +
> >> +void cpu_ppc_set_papr(PowerPCCPU *cpu)
> >> +{
> >> + CPUPPCState *env = &cpu->env;
> >> + ppc_spr_t *lpcr = &env->spr_cb[SPR_LPCR];
> >> +
> >> + /* PAPR always has exception vectors in RAM not ROM. To ensure this,
> >> + * MSR[IP] should never be set.
> >> + *
> >> + * We also disallow setting of MSR_HV
> >> + */
> >> + 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
> >> + */
> >> + lpcr->default_value &= ~(LPCR_VPM0 | LPCR_VPM1 | LPCR_ISL | LPCR_KBV);
> >> + lpcr->default_value |= LPCR_LPES0 | LPCR_LPES1;
> >> +
> >> + /* We should be followed by a CPU reset but update the active value
> >> + * just in case...
> >> + */
> >> + env->spr[SPR_LPCR] = lpcr->default_value;
> >> +
> >> + /* Tell KVM that we're in PAPR mode */
> >> + if (kvm_enabled()) {
> >> + kvmppc_set_papr(cpu);
> >> + }
> >> +}
> >> +
> >> +#endif /* !defined(CONFIG_USER_ONLY) */
> >> +
> >> +#endif /* defined (TARGET_PPC64) */
> >>
> >>
> >> /*****************************************************************************/
> >> /* Generic CPU instantiation routine
> >> */
> >
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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