Re: [Qemu-ppc] [PATCH v4] spapr-rtas: add ibm, get-vpd RTAS interface

[Murilo Opsfelder Araujo]

Hi, Maxiwell.

On Thu, Feb 28, 2019 at 05:04:37PM -0300, Maxiwell S. Garcia 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    | 121 +++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h |  17 +++++-
>  2 files changed, 137 insertions(+), 1 deletion(-)
>
> Update v4:
>     * Allows enable/disable host-serial and host-model options individually
>
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index 7a2cb786a3..785c453eb6 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -287,6 +287,123 @@ 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,
> +                         const void *val, uint16_t val_len)
> +{
> +    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)
> +{
> +    rtas_st(rets, 0, status);
> +    rtas_st(rets, 1, next_seq_number);
> +    rtas_st(rets, 2, bytes_returned);
> +}
> +
> +static void rtas_ibm_get_vpd_register_keywords(sPAPRMachineState *sm)
> +{
> +    sm->rtas_vpd_keywords = g_malloc0(sizeof(uint8_t) *
> +                            RTAS_IBM_VPD_KEYWORDS_MAX);
> +
> +    int i = 0;
> +    if (sm->host_serial && !g_str_equal(sm->host_serial, "none")) {
> +        sm->rtas_vpd_keywords[i++] = RTAS_IBM_VPD_KEYWORD_SE;
> +    }
> +    if (sm->host_model && !g_str_equal(sm->host_model, "none")) {
> +        sm->rtas_vpd_keywords[i++] = RTAS_IBM_VPD_KEYWORD_TM;
> +    }
> +}
> +
> +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;
> +    target_ulong work_area_addr;
> +    target_ulong work_area_size;
> +    target_ulong seq_number;
> +    unsigned char loc_code = 0;
> +    unsigned int next_seq_number = 1;
> +    int status = RTAS_IBM_GET_VPD_PARAMETER_ERROR;
> +    int ret = RTAS_OUT_PARAM_ERROR;
> +    char *buf = NULL;
> +    char *vpd_field = NULL;
> +    unsigned int vpd_field_len = 0;
> +
> +    /* RTAS not authorized if no keywords have been registered */
> +    if (!spapr->rtas_vpd_keywords[0]) {
> +        vpd_ret(rets, RTAS_OUT_NOT_AUTHORIZED, 1, 0);
> +        return;
> +    }
> +
> +    loc_code_addr = rtas_ld(args, 0);
> +    work_area_addr = rtas_ld(args, 1);
> +    work_area_size = rtas_ld(args, 2);
> +    seq_number = rtas_ld(args, 3);
> +
> +    /* 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_VPD_KEYWORDS_MAX)) {
> +        vpd_ret(rets, RTAS_IBM_GET_VPD_PARAMETER_ERROR, 1, 0);
> +        return;
> +    }
> +
> +    switch (spapr->rtas_vpd_keywords[seq_number - 1]) {

Since seq_number comes from guest userspace, we shouldn't rely its
value will always be within the range of the array.

We could perhaps return RTAS_OUT_NOT_AUTHORIZED if `seq_number - 1`
extrapolates the array range that holds the registered keywords.

> +    case RTAS_IBM_VPD_KEYWORD_SE:
> +        if (g_str_equal(spapr->host_serial, "passthrough")) {
> +            /* -M host-serial=passthrough */
> +            if (kvmppc_get_host_serial(&buf)) {
> +                /* LoPAPR: SE for Machine or Cabinet Serial Number */
> +                vpd_field = g_strdup_printf("SE %s", buf);
> +            }
> +        } else {
> +            vpd_field = g_strdup_printf("SE %s", spapr->host_serial);
> +        }
> +        break;
> +    case RTAS_IBM_VPD_KEYWORD_TM:
> +        if (g_str_equal(spapr->host_model, "passthrough")) {
> +            /* -M host-model=passthrough */
> +            if (kvmppc_get_host_model(&buf)) {
> +                /* LoPAPR: TM for Machine Type and Model */
> +                vpd_field = g_strdup_printf("TM %s", buf);
> +            }
> +        } else {
> +            vpd_field = g_strdup_printf("TM %s", spapr->host_model);
> +        }
> +        break;
> +    }
> +
> +    if (vpd_field) {
> +        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_vpd_keywords[next_seq_number - 1]) {
> +                status = RTAS_IBM_GET_VPD_CONTINUE;
> +            } else {
> +                status = RTAS_IBM_GET_VPD_SUCCESS;
> +                next_seq_number = 1;

If spapr->rtas_vpd_keywords[next_seq_number - 1] doesn't exist,
shouldn't we set next_seq_number=RTAS_IBM_VPD_KEYWORDS_MAX here,
indicating next_seq_number reached the last registered keyword?

> +            }
> +        }
> +    }
> +
> +    vpd_ret(rets, status, next_seq_number, vpd_field_len);
> +    g_free(vpd_field);
> +    g_free(buf);
> +}
> +
>  static void rtas_ibm_os_term(PowerPCCPU *cpu,
>                              sPAPRMachineState *spapr,
>                              uint32_t token, uint32_t nargs,
> @@ -464,6 +581,8 @@ void spapr_load_rtas(sPAPRMachineState *spapr, void *fdt, 
> hwaddr addr)
>                       fdt_strerror(ret));
>          exit(1);
>      }
> +
> +    rtas_ibm_get_vpd_register_keywords(spapr);
>  }
>
>  static void core_rtas_register_types(void)
> @@ -485,6 +604,8 @@ 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 59073a7579..ebf314a15c 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -153,6 +153,7 @@ struct sPAPRMachineState {
>      struct PPCTimebase tb;
>      bool has_graphics;
>      uint32_t vsmt;       /* Virtual SMT mode (KVM's "core stride") */
> +    uint8_t *rtas_vpd_keywords;
>
>      Notifier epow_notifier;
>      QTAILQ_HEAD(, sPAPREventLogEntry) pending_events;
> @@ -608,14 +609,28 @@ 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 values */
> +#define RTAS_IBM_GET_VPD_VPD_CHANGED     -4
> +#define RTAS_IBM_GET_VPD_PARAMETER_ERROR -3
> +#define RTAS_IBM_GET_VPD_HARDWARE_ERROR  -1
> +#define RTAS_IBM_GET_VPD_SUCCESS          0
> +#define RTAS_IBM_GET_VPD_CONTINUE         1
> +
> +/* RTAS ibm,get-vpd keywords index */
> +#define RTAS_IBM_VPD_KEYWORD_SE     1
> +#define RTAS_IBM_VPD_KEYWORD_TM     2
> +
> +#define RTAS_IBM_VPD_KEYWORDS_MAX   2
> +
>  /* RTAS indicator/sensor types
>   *
>   * as defined by PAPR+ 2.7 7.3.5.4, Table 41
> --
> 2.20.1
>
>

--
Murilo