Re: [Qemu-devel] [Qemu-ppc] [PATCH v6 2/2] spapr-rtas: add ibm, get-vpd RTAS interface

[Maxiwell S. Garcia]

On Thu, Mar 14, 2019 at 06:26:02PM +0100, Greg Kurz wrote:
> On Thu, 14 Mar 2019 13:29:49 -0300
> "Maxiwell S. Garcia" <address@hidden> wrote:
> 
> > This adds a handler for ibm,get-vpd RTAS calls, allowing pseries guest
> > to collect host information. It is disabled by default to avoid unwanted
> > information leakage. To enable it, use:
> > 
> > -M pseries,host-serial={passthrough|string},host-model={passthrough|string}
> > 
> > Only the SE and TM keywords are returned at the moment.
> > SE for Machine or Cabinet Serial Number and
> > TM for Machine Type and Model
> > 
> > The SE and TM keywords are controlled by 'host-serial' and 'host-model'
> > options, respectively. In the case of 'passthrough', the SE shows the
> > host 'system-id' information and the TM shows the host 'model' information.
> > 
> > Powerpc-utils tools can dispatch RTAS calls to retrieve host
> > information using this ibm,get-vpd interface. The 'host-serial'
> > and 'host-model' nodes of device-tree hold the same information but
> > in a static manner, which is useless after a migration operation.
> > 
> > Signed-off-by: Maxiwell S. Garcia <address@hidden>
> > ---
> >  hw/ppc/spapr_rtas.c    | 99 ++++++++++++++++++++++++++++++++++++++++++
> >  include/hw/ppc/spapr.h |  7 ++-
> >  2 files changed, 105 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> > index 24c45b12d4..8ab092c67b 100644
> > --- a/hw/ppc/spapr_rtas.c
> > +++ b/hw/ppc/spapr_rtas.c
> > @@ -287,6 +287,101 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU 
> > *cpu,
> >      rtas_st(rets, 0, ret);
> >  }
> >  
> > +static inline int vpd_st(target_ulong addr, target_ulong len,PARAM
> > +                         const void *val, uint16_t val_len)
> 
> I see no compelling reason to make this inline. Better to let the
> compiler decide.
> 
> > +{
> > +    hwaddr phys = ppc64_phys_to_real(addr);
> > +
> > +    if (len < val_len) {
> > +        return RTAS_OUT_PARAM_ERROR;
> > +    }
> > +
> > +    cpu_physical_memory_write(phys, val, val_len);
> > +    return RTAS_OUT_SUCCESS;
> > +}
> > +
> > +static inline void vpd_ret(target_ulong rets, const int status,
> > +                           const int next_seq_number, const int 
> > bytes_returned)
> 
> Same here.
> 
> > +{
> > +    rtas_st(rets, 0, status);
> > +    rtas_st(rets, 1, next_seq_number);
> > +    rtas_st(rets, 2, bytes_returned);
> > +}
> > +
> > +/* Maximum number of ibm,get-vpd fields supported */
> > +#define RTAS_IBM_GET_VPD_MAX 2
> > +
> > +static void rtas_ibm_get_vpd_fields_register(SpaprMachineState *spapr)
> > +{
> > +    int i = 0;
> > +    char *buf = NULL;
> > +
> > +    spapr->rtas_get_vpd_fields = g_malloc0(sizeof(char *) *
> > +                                 RTAS_IBM_GET_VPD_MAX + 1);
> 
> As suggested in HACKING, better to use g_new0() here.
> 
> Also, this gets called during machine reset, ie, this would cause a
> memory leak each time we do system_reset... you should do g_free()
> before g_new0().
> 
> Thinking again, it is a bit suboptimal to free and re-allocate the same
> fixed size array again and again, even if reset isn't a performance path.
> It could be be a regular array under spapr I guess and you would only need
> to memset(0) I guess...
> 
> David ? What was the motivation to ask Maxiwell to go for a dynamic
> allocation ?
> 

Can I send a v7 patch creating the rtas_get_vpd_fields array as a regular array
under spapr, avoiding dynamic allocation?

> > +
> > +    buf = spapr_get_valid_host_serial(spapr);
> > +    if (buf) {
> > +        spapr->rtas_get_vpd_fields[i++] = g_strdup_printf("SE %s", buf);
> > +        g_free(buf);
> > +    }
> > +
> > +    buf = spapr_get_valid_host_model(spapr);
> > +    if (buf) {
> > +        spapr->rtas_get_vpd_fields[i++] = g_strdup_printf("TM %s", buf);
> > +        g_free(buf);PARAM
> > +    }
> > +}
> > +
> > +static void rtas_ibm_get_vpd(PowerPCCPU *cpu,
> > +                             SpaprMachineState *spapr,
> > +                             uint32_t token, uint32_t nargs,
> > +                             target_ulong args,
> > +                             uint32_t nret, target_ulong rets)
> > +{
> > +    target_ulong loc_code_addr = rtas_ld(args, 0);
> > +    target_ulong work_area_addr = rtas_ld(args, 1);
> > +    target_ulong work_area_size = rtas_ld(args, 2);
> > +    target_ulong seq_number = rtas_ld(args, 3);
> > +    unsigned char loc_code = 0;
> > +    unsigned int next_seq_number = 1;
> > +    int status = RTAS_OUT_PARAM_ERROR;
> > +    int ret = RTAS_OUT_PARAM_ERROR;
> > +    char *vpd_field = NULL;
> > +    unsigned int vpd_field_len = 0;
> 
> It looks like loc_code, status, ret, vpd_field and vpd_field_len always
> get set in the code and don't need default values...
> 
> > +
> > +    /* Specific Location Code is not supported and seq_number */
> > +    /* must be checked to avoid out of bound index error */
> > +    cpu_physical_memory_read(loc_code_addr, &loc_code, 1);
> > +    if ((loc_code != 0) || (seq_number <= 0) ||
> > +        (seq_number > RTAS_IBM_GET_VPD_MAX)) {
> > +        vpd_ret(rets, RTAS_OUT_PARAM_ERROR, 1, 0);
> > +        return;
> > +    }
> > +
> > +    /* RTAS not authorized if no keywords have been registered */
> > +    if (!spapr->rtas_get_vpd_fields[seq_number - 1]) {
> > +        vpd_ret(rets, RTAS_OUT_NOT_AUTHORIZED, 1, 0);
> > +        return;
> > +    }
> > +
> > +    vpd_field = spapr->rtas_get_vpd_fields[seq_number - 1];
> > +    vpd_field_len = strlen(vpd_field);
> > +    ret = vpd_st(work_area_addr, work_area_size,
> > +                 vpd_field, vpd_field_len + 1);
> > +
> > +    if (ret == 0) {
> > +        next_seq_number = seq_number + 1;
> > +        if (spapr->rtas_get_vpd_fields[next_seq_number - 1]) {
> > +            status = RTAS_IBM_GET_VPD_CONTINUE;
> > +        } else {
> > +            status = RTAS_OUT_SUCCESS;
> > +            next_seq_number = 1;
> > +        }
> > +    }
> > +
> > +    vpd_ret(rets, status, next_seq_number, vpd_field_len);
> > +}
> > +
> >  static void rtas_ibm_os_term(PowerPCCPU *cpu,
> >                              SpaprMachineState *spapr,
> >                              uint32_t token, uint32_t nargs,
> > @@ -464,6 +559,8 @@ void spapr_load_rtas(SpaprMachineState *spapr, void 
> > *fdt, hwaddr addr)
> >                       fdt_strerror(ret));
> >          exit(1);
> >      }
> > +
> > +    rtas_ibm_get_vpd_fields_register(spapr);
> >  }
> >  
> >  static void core_rtas_register_types(void)
> > @@ -485,6 +582,8 @@ static void core_rtas_register_types(void)
> >                          rtas_ibm_set_system_parameter);
> >      spapr_rtas_register(RTAS_IBM_OS_TERM, "ibm,os-term",
> >                          rtas_ibm_os_term);
> > +    spapr_rtas_register(RTAS_IBM_GET_VPD, "ibm,get-vpd",
> > +                        rtas_ibm_get_vpd);
> >      spapr_rtas_register(RTAS_SET_POWER_LEVEL, "set-power-level",
> >                          rtas_set_power_level);
> >      spapr_rtas_register(RTAS_GET_POWER_LEVEL, "get-power-level",
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 5e0a1b2a8a..34bb835bd3 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -162,6 +162,7 @@ struct SpaprMachineState {
> >      struct PPCTimebase tb;
> >      bool has_graphics;
> >      uint32_t vsmt;       /* Virtual SMT mode (KVM's "core stride") */
> > +    char **rtas_get_vpd_fields;
> >  
> >      Notifier epow_notifier;
> >      QTAILQ_HEAD(, SpaprEventLogEntry) pending_events;
> > @@ -619,14 +620,18 @@ 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_GET_VPD                        (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
> >  #define RTAS_SYSPARM_DIAGNOSTICS_RUN_MODE        42
> >  #define RTAS_SYSPARM_UUID                        48
> >  
> > +/* RTAS ibm,get-vpd status value */
> > +#define RTAS_IBM_GET_VPD_CONTINUE 1
> > +
> >  /* RTAS indicator/sensor types
> >   *
> >   * as defined by PAPR+ 2.7 7.3.5.4, Table 41
> 
>