Re: [Qemu-devel] [PATCH v5 3/4] sPAPR: Support RTAS call ibm, {open, close}-errinjct

[Thomas Huth <thuth@redhat.com>]

On 17/08/15 18:47, Gavin Shan wrote:
> The patch supports RTAS calls "ibm,{open,close}-errinjct" to
> manupliate the token, which is passed to RTAS call "ibm,errinjct"
> to indicate the valid context for error injection. Each VM is
> permitted to have only one token at once and we simply have one
> random number for that.

Looking at the code, you're using a sequence number now instead of a
random number?

> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> ---
>  hw/ppc/spapr.c         |  6 ++++-
>  hw/ppc/spapr_rtas.c    | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h | 10 +++++++-
>  3 files changed, 80 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 06d000d..591a1a7 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1191,7 +1191,7 @@ static bool version_before_3(void *opaque, int version_id)
>  
>  static const VMStateDescription vmstate_spapr = {
>      .name = "spapr",
> -    .version_id = 3,
> +    .version_id = 4,
>      .minimum_version_id = 1,
>      .post_load = spapr_post_load,
>      .fields = (VMStateField[]) {
> @@ -1202,6 +1202,10 @@ static const VMStateDescription vmstate_spapr = {
>          VMSTATE_UINT64_TEST(rtc_offset, sPAPRMachineState, version_before_3),
>  
>          VMSTATE_PPC_TIMEBASE_V(tb, sPAPRMachineState, 2),
> +
> +        /* Error injection token */
> +        VMSTATE_UINT32_V(errinjct_token, sPAPRMachineState, 4),

Ok, so you're only saving the errinjct_token here, but not
is_errinjct_opened?

>          VMSTATE_END_OF_LIST()
>      },
>  };
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index e99e25f..8405056 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -604,6 +604,68 @@ out:
>      rtas_st(rets, 0, rc);
>  }
>  
> +static void rtas_ibm_open_errinjct(PowerPCCPU *cpu,
> +                                   sPAPRMachineState *spapr,
> +                                   uint32_t token, uint32_t nargs,
> +                                   target_ulong args, uint32_t nret,
> +                                   target_ulong rets)
> +{
> +    int32_t ret;
> +
> +    /* Sanity check on number of arguments */
> +    if ((nargs != 0) || (nret != 2)) {

Uh, did Alexey infect you with paranthesitis?

> +        ret = RTAS_OUT_PARAM_ERROR;
> +        goto out;
> +    }
> +
> +    /* Check if we already had token */
> +    if (spapr->is_errinjct_opened) {
> +        ret = RTAS_OUT_TOKEN_OPENED;
> +        goto out;
> +    }
> +
> +    /* Grab the token */
> +    spapr->is_errinjct_opened = true;
> +    rtas_st(rets, 0, ++spapr->errinjct_token);
> +    ret = RTAS_OUT_SUCCESS;
> +out:
> +    rtas_st(rets, 1, ret);
> +}
> +
> +static void rtas_ibm_close_errinjct(PowerPCCPU *cpu,
> +                                    sPAPRMachineState *spapr,
> +                                    uint32_t token, uint32_t nargs,
> +                                    target_ulong args, uint32_t nret,
> +                                    target_ulong rets)
> +{
> +    uint32_t open_token;
> +    int32_t ret;
> +
> +    /* Sanity check on number of arguments */
> +    if ((nargs != 1) || (nret != 1)) {
> +        ret = RTAS_OUT_PARAM_ERROR;
> +        goto out;
> +    }
> +
> +    /* Check if we had opened token */
> +    if (!spapr->is_errinjct_opened) {
> +        ret = RTAS_OUT_CLOSE_ERROR;
> +        goto out;
> +    }

... and here you check that another status variable "is_errinjct_opened"
which is not saved in the VMStateDescription and thus this information
will get lost during migration, I think. That looks like a bug to me.

Can you do your code completely without "is_errinjct_opened"? I.e. by
using errinjct_token == 0 for signalling that no injection progress is
currently taking place?

> +    /* Match with the passed token */
> +    open_token = rtas_ld(args, 0);
> +    if (spapr->errinjct_token != open_token) {
> +        ret = RTAS_OUT_CLOSE_ERROR;
> +        goto out;
> +    }
> +
> +    spapr->is_errinjct_opened = false;
> +    ret = RTAS_OUT_SUCCESS;
> +out:
> +    rtas_st(rets, 0, ret);
> +}

 Thomas