Re: [Qemu-devel] [PATCH v2 3/3] spapr: Implement ibm,suspend-me

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jul 22, 2019 at 04:17:52PM +1000, Nicholas Piggin wrote:
> This has been useful to modify and test the Linux pseries suspend
> code but it requires modification to the guest to call it (due to
> being gated by other unimplemented features). It is not otherwise
> used by Linux yet, but work is slowly progressing there.
> 
> This allows a (lightly modified) guest kernel to suspend with
> `echo mem > /sys/power/state` and be resumed with system_wakeup
> monitor command.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Acked-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  hw/ppc/spapr.c         |  7 +++++++
>  hw/ppc/spapr_rtas.c    | 32 ++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h |  3 ++-
>  3 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 00f7735a31..a580466d01 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3078,6 +3078,13 @@ static void spapr_machine_init(MachineState *machine)
>  
>      qemu_register_boot_set(spapr_boot_set, spapr);
>  
> +    /*
> +     * Nothing needs to be done to resume a suspended guest because
> +     * suspending does not change the machine state, so no need for
> +     * a ->wakeup method.
> +     */
> +    qemu_register_wakeup_support();
> +
>      if (kvm_enabled()) {
>          /* to stop and start vmclock */
>          qemu_add_vm_change_state_handler(cpu_ppc_clock_vm_state_change,
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index a618a2ac0f..87175c1e0a 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -216,6 +216,36 @@ static void rtas_stop_self(PowerPCCPU *cpu, SpaprMachineState *spapr,
>      qemu_cpu_kick(cs);
>  }
>  
> +static void rtas_ibm_suspend_me(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                           uint32_t token, uint32_t nargs,
> +                           target_ulong args,
> +                           uint32_t nret, target_ulong rets)
> +{
> +    CPUState *cs;
> +
> +    if (nargs != 0 || nret != 1) {
> +        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> +        return;
> +    }
> +
> +    CPU_FOREACH(cs) {
> +        PowerPCCPU *c = POWERPC_CPU(cs);
> +        CPUPPCState *e = &c->env;
> +        if (c == cpu) {
> +            continue;
> +        }
> +
> +        /* See h_join */
> +        if (!cs->halted || (e->msr & (1ULL << MSR_EE))) {
> +            rtas_st(rets, 0, H_MULTI_THREADS_ACTIVE);
> +            return;
> +        }
> +    }
> +
> +    qemu_system_suspend_request();
> +    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> +}
> +
>  static inline int sysparm_st(target_ulong addr, target_ulong len,
>                               const void *val, uint16_t vallen)
>  {
> @@ -483,6 +513,8 @@ static void core_rtas_register_types(void)
>                          rtas_query_cpu_stopped_state);
>      spapr_rtas_register(RTAS_START_CPU, "start-cpu", rtas_start_cpu);
>      spapr_rtas_register(RTAS_STOP_SELF, "stop-self", rtas_stop_self);
> +    spapr_rtas_register(RTAS_IBM_SUSPEND_ME, "ibm,suspend-me",
> +                        rtas_ibm_suspend_me);
>      spapr_rtas_register(RTAS_IBM_GET_SYSTEM_PARAMETER,
>                          "ibm,get-system-parameter",
>                          rtas_ibm_get_system_parameter);
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 5d36eec9d0..6e8e18b077 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -631,8 +631,9 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong opcode,
>  #define RTAS_IBM_CREATE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x27)
>  #define RTAS_IBM_REMOVE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x28)
>  #define RTAS_IBM_RESET_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x29)
> +#define RTAS_IBM_SUSPEND_ME                     (RTAS_TOKEN_BASE + 0x2A)
>  
> -#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2A)
> +#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2B)
>  
>  /* RTAS ibm,get-system-parameter token values */
>  #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20

-- 
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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