On Sat, Nov 21, 2020 at 12:42:03AM +0100, Greg Kurz wrote:
> When it comes to resetting the compat mode of the vCPUS, there are
> two situations to consider:
> (1) machine reset should set the compat mode back to the machine default,
> ie. spapr->max_compat_pvr
> (2) hot plugged vCPUs should set their compat mode to mach the boot vCPU,
> ie. POWERPC_CPU(first_cpu)->compat_pvr
>
> This is currently handled in two separate places: globally for all vCPUs
> from the machine reset code for (1) and for each thread of a core from
> the hotplug path for (2).
>
> Since the machine reset code already resets all vCPUs, starting with boot
> vCPU, consolidate the logic in spapr_reset_vcpu(). Special case the boot
> vCPU so that it resets its compat mode back to the machine default. Any
> other vCPU just need to match the compat mode of the boot vCPU.
>
> Failing to set the compat mode during machine reset is a fatal error,
> but not for hot plugged vCPUs. This is arguable because if we've been
> able to set the boot vCPU compat mode at CAS or during machine reset,
> it should definitely not fail for other vCPUs. Since spapr_reset_vcpu()
> already has a fatal error path for kvm_check_mmu() failures, do the
> same for ppc_set_compat().
>
> This gets rid of an error path in spapr_core_plug(). It will allow
> further simplifications.
>
> Signed-off-by: Greg Kurz <gr...@kaod.org>
> ---
> hw/ppc/spapr.c | 16 ----------------
> hw/ppc/spapr_cpu_core.c | 13 +++++++++++++
> 2 files changed, 13 insertions(+), 16 deletions(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index f58f77389e8e..da7586f548df 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1606,8 +1606,6 @@ static void spapr_machine_reset(MachineState *machine)
> spapr_ovec_cleanup(spapr->ov5_cas);
> spapr->ov5_cas = spapr_ovec_new();
>
> - ppc_set_compat_all(spapr->max_compat_pvr, &error_fatal);
> -
> /*
> * This is fixing some of the default configuration of the XIVE
> * devices. To be called after the reset of the machine devices.
> @@ -3785,20 +3783,6 @@ static void spapr_core_plug(HotplugHandler
> *hotplug_dev, DeviceState *dev,
>
> core_slot->cpu = OBJECT(dev);
>
> - /*
> - * Set compatibility mode to match the boot CPU, which was either set
> - * by the machine reset code or by CAS.
> - */
> - if (hotplugged) {
> - for (i = 0; i < cc->nr_threads; i++) {
> - if (ppc_set_compat(core->threads[i],
> - POWERPC_CPU(first_cpu)->compat_pvr,
> - errp) < 0) {
> - return;
> - }
> - }
> - }
> -
> if (smc->pre_2_10_has_unused_icps) {
> for (i = 0; i < cc->nr_threads; i++) {
> cs = CPU(core->threads[i]);
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 2f7dc3c23ded..17741a3fb77f 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -27,6 +27,7 @@
>
> static void spapr_reset_vcpu(PowerPCCPU *cpu)
> {
> + PowerPCCPU *first_ppc_cpu = POWERPC_CPU(first_cpu);
> CPUState *cs = CPU(cpu);
> CPUPPCState *env = &cpu->env;
> PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
> @@ -69,6 +70,18 @@ static void spapr_reset_vcpu(PowerPCCPU *cpu)
> kvm_check_mmu(cpu, &error_fatal);
>
> spapr_irq_cpu_intc_reset(spapr, cpu);
> +
> + /*
> + * The boot CPU is only reset during machine reset : reset its
> + * compatibility mode to the machine default. For other CPUs,
> + * either cold plugged or hot plugged, set the compatibility mode
> + * to match the boot CPU, which was either set by the machine reset
> + * code or by CAS.
> + */
> + ppc_set_compat(cpu,
> + cpu == first_ppc_cpu ?
> + spapr->max_compat_pvr : first_ppc_cpu->compat_pvr,
> + &error_fatal);
This assumes that when it is called for a non-boot CPU, it has already
been called for the boot CPU.. Are we certain that's guaranteed by
the sequence of reset calls during a full machine reset?
> }
>
> void spapr_cpu_set_entry_state(PowerPCCPU *cpu, target_ulong nip,
--
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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