Re: [Qemu-devel] [PATCH v6 07/15] spapr_rtas: add ibm, configure-connector RTAS interface

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

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On Thu, Feb 26, 2015 at 09:11:07PM -0600, Michael Roth wrote:
> This interface is used to fetch an OF device-tree nodes that describes a
> newly-attached device to guest. It is called multiple times to walk the
> device-tree node and fetch individual properties into a 'workarea'/buffer
> provided by the guest.
> 
> The device-tree is generated by QEMU and passed to an sPAPRDRConnector during
> the initial hotplug operation, and the state of these RTAS calls is tracked by
> the sPAPRDRConnector. When the last of these properties is successfully
> fetched, we report as special return value to the guest and transition
> the device to a 'configured' state on the QEMU/DRC side.
> 
> See docs/specs/ppc-spapr-hotplug.txt for a complete description of
> this interface.
> 
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>


So, actually, here's probably the best place to explain what I had in
mind for changing the internal interface for this stuff.  I was
thinking something like this pseudocode:

struct DRCCCState {
	void *fdt;
	int offset;
	int depth;
};

rtas_configure_connector()
{
	...
	DRCCCState *ccstate;
	...

	/* check parameters, retrieve drc */
	ccstate = drc->ccstate;

	if (!ccstate) {
		/* Haven't started configuring yet */
		ccstate = malloc(...);
		/* Retrieve the dt fragment from the backend */
		ccstate->fdt = drck->get_dt(...);
		ccstate->offset = 0;
	}

	while (get next tag from fdt) {
		switch (tag)
		case FDT_PROPERTY:
	      		/* Translate property into rtas return values */
			return SPAPR_DR_CC_RESPONSE_NEXT_PROPERTY;

		/* other cases ... */
	}
	
	/* Fall through only if we've completed streaming out the dt
	*/

	 /* Tell the back end we've finished configuring */
	drck->cc_completed(...);
	return SPAPR_DR_CC_RESPONSE_SUCCESS;
}

On reset, or anything else which interrupts the configuration process,
just blow away drc->ccstate.


> ---
>  hw/ppc/spapr_rtas.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 88 insertions(+)
> 
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index f80beb2..31ad35f 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -418,6 +418,92 @@ static void rtas_get_sensor_state(PowerPCCPU *cpu, sPAPREnvironment *spapr,
>      rtas_st(rets, 1, entity_sense);
>  }
>  
> +/* configure-connector work area offsets, int32_t units for field
> + * indexes, bytes for field offset/len values.
> + *
> + * as documented by PAPR+ v2.7, 13.5.3.5
> + */
> +#define CC_IDX_NODE_NAME_OFFSET 2
> +#define CC_IDX_PROP_NAME_OFFSET 2
> +#define CC_IDX_PROP_LEN 3
> +#define CC_IDX_PROP_DATA_OFFSET 4
> +#define CC_VAL_DATA_OFFSET ((CC_IDX_PROP_DATA_OFFSET + 1) * 4)
> +#define CC_WA_LEN 4096
> +
> +static void rtas_ibm_configure_connector(PowerPCCPU *cpu,
> +                                         sPAPREnvironment *spapr,
> +                                         uint32_t token, uint32_t nargs,
> +                                         target_ulong args, uint32_t nret,
> +                                         target_ulong rets)
> +{
> +    uint64_t wa_addr;
> +    uint64_t wa_offset;
> +    uint32_t drc_index;
> +    sPAPRDRConnector *drc;
> +    sPAPRDRConnectorClass *drck;
> +    sPAPRDRCCResponse resp;
> +    const struct fdt_property *prop = NULL;
> +    char *prop_name = NULL;
> +    int prop_len, rc;
> +
> +    if (nargs != 2 || nret != 1) {
> +        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> +        return;
> +    }
> +
> +    wa_addr = ((uint64_t)rtas_ld(args, 1) << 32) | rtas_ld(args, 0);
> +
> +    drc_index = rtas_ld(wa_addr, 0);
> +    drc = spapr_dr_connector_by_index(drc_index);
> +    if (!drc) {
> +        DPRINTF("rtas_ibm_configure_connector: invalid sensor/DRC index: %xh\n",
> +                drc_index);
> +        rc = RTAS_OUT_PARAM_ERROR;
> +        goto out;
> +    }
> +    drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> +    resp = drck->configure_connector(drc, &prop_name, &prop, &prop_len);
> +
> +    switch (resp) {
> +    case SPAPR_DR_CC_RESPONSE_NEXT_CHILD:
> +        /* provide the name of the next OF node */
> +        wa_offset = CC_VAL_DATA_OFFSET;
> +        rtas_st(wa_addr, CC_IDX_NODE_NAME_OFFSET, wa_offset);
> +        rtas_st_buffer_direct(wa_addr + wa_offset, CC_WA_LEN - wa_offset,
> +                              (uint8_t *)prop_name, strlen(prop_name) + 1);
> +        break;
> +    case SPAPR_DR_CC_RESPONSE_NEXT_PROPERTY:
> +        /* provide the name of the next OF property */
> +        wa_offset = CC_VAL_DATA_OFFSET;
> +        rtas_st(wa_addr, CC_IDX_PROP_NAME_OFFSET, wa_offset);
> +        rtas_st_buffer_direct(wa_addr + wa_offset, CC_WA_LEN - wa_offset,
> +                              (uint8_t *)prop_name, strlen(prop_name) + 1);
> +
> +        /* provide the length and value of the OF property. data gets placed
> +         * immediately after NULL terminator of the OF property's name string
> +         */
> +        wa_offset += strlen(prop_name) + 1,
> +        rtas_st(wa_addr, CC_IDX_PROP_LEN, prop_len);
> +        rtas_st(wa_addr, CC_IDX_PROP_DATA_OFFSET, wa_offset);
> +        rtas_st_buffer_direct(wa_addr + wa_offset, CC_WA_LEN - wa_offset,
> +                              (uint8_t *)((struct fdt_property *)prop)->data,
> +                              prop_len);
> +        break;
> +    case SPAPR_DR_CC_RESPONSE_PREV_PARENT:
> +    case SPAPR_DR_CC_RESPONSE_ERROR:
> +    case SPAPR_DR_CC_RESPONSE_SUCCESS:
> +        break;
> +    default:
> +        /* drck->configure_connector() should not return anything else */
> +        g_assert(false);
> +    }
> +
> +    rc = resp;
> +out:
> +    g_free(prop_name);
> +    rtas_st(rets, 0, rc);
> +}
> +
>  static struct rtas_call {
>      const char *name;
>      spapr_rtas_fn fn;
> @@ -551,6 +637,8 @@ static void core_rtas_register_types(void)
>                          rtas_set_indicator);
>      spapr_rtas_register(RTAS_GET_SENSOR_STATE, "get-sensor-state",
>                          rtas_get_sensor_state);
> +    spapr_rtas_register(RTAS_IBM_CONFIGURE_CONNECTOR, "ibm,configure-connector",
> +                        rtas_ibm_configure_connector);
>  }
>  
>  type_init(core_rtas_register_types)

-- 
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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