Re: [PATCH 10/19] smbios: handle errors consistently

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 4 Mar 2024 16:44:34 +0530 (IST)
Ani Sinha <anisinha@redhat.com> wrote:

> On Tue, 27 Feb 2024, Igor Mammedov wrote:
> 
> > Current code uses mix of error_report()+exit(1)
> > and error_setg() to handle errors.
> > Use newer error_setg() everywhere, beside consistency
> > it will allow to detect error condition without killing
> > QEMU and attempt switch-over to SMBIOS3.x tables/entrypoint
> > in follow up patch.
> >
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>  
> 
> Other than the nit below,
> 
> Reviewed-by: Ani Sinha <anisinha@redhat.com>
> 
> > ---
> >  include/hw/firmware/smbios.h |  4 ++--
> >  hw/i386/fw_cfg.c             |  3 ++-
> >  hw/smbios/smbios.c           | 32 ++++++++++++++++++++------------
> >  hw/smbios/smbios_legacy.c    | 22 ++++++++++++++--------
> >  4 files changed, 38 insertions(+), 23 deletions(-)
> >
> > diff --git a/include/hw/firmware/smbios.h b/include/hw/firmware/smbios.h
> > index a6d8fd6591..d1194c9cc2 100644
> > --- a/include/hw/firmware/smbios.h
> > +++ b/include/hw/firmware/smbios.h
> > @@ -310,7 +310,7 @@ struct smbios_type_127 {
> >      struct smbios_structure_header header;
> >  } QEMU_PACKED;
> >
> > -void smbios_validate_table(void);
> > +bool smbios_validate_table(Error **errp);
> >  void smbios_add_usr_blob_size(size_t size);
> >  void smbios_entry_add(QemuOpts *opts, Error **errp);
> >  void smbios_set_cpuid(uint32_t version, uint32_t features);
> > @@ -318,7 +318,7 @@ void smbios_set_defaults(const char *manufacturer, const char *product,
> >                           const char *version,
> >                           bool uuid_encoded, SmbiosEntryPointType ep_type);
> >  void smbios_set_default_processor_family(uint16_t processor_family);
> > -uint8_t *smbios_get_table_legacy(size_t *length);
> > +uint8_t *smbios_get_table_legacy(size_t *length, Error **errp);
> >  void smbios_get_tables(MachineState *ms,
> >                         const struct smbios_phys_mem_area *mem_array,
> >                         const unsigned int mem_array_size,
> > diff --git a/hw/i386/fw_cfg.c b/hw/i386/fw_cfg.c
> > index d1281066f4..e387bf50d0 100644
> > --- a/hw/i386/fw_cfg.c
> > +++ b/hw/i386/fw_cfg.c
> > @@ -71,7 +71,8 @@ void fw_cfg_build_smbios(PCMachineState *pcms, FWCfgState *fw_cfg)
> >      smbios_set_cpuid(cpu->env.cpuid_version, cpu->env.features[FEAT_1_EDX]);
> >
> >      if (pcmc->smbios_legacy_mode) {
> > -        smbios_tables = smbios_get_table_legacy(&smbios_tables_len);
> > +        smbios_tables = smbios_get_table_legacy(&smbios_tables_len,
> > +                                                &error_fatal);
> >          fw_cfg_add_bytes(fw_cfg, FW_CFG_SMBIOS_ENTRIES,
> >                           smbios_tables, smbios_tables_len);
> >          return;
> > diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> > index fb1f05fcde..7c28b5f748 100644
> > --- a/hw/smbios/smbios.c
> > +++ b/hw/smbios/smbios.c
> > @@ -19,7 +19,6 @@
> >  #include "qemu/units.h"
> >  #include "qapi/error.h"
> >  #include "qemu/config-file.h"
> > -#include "qemu/error-report.h"
> >  #include "qemu/module.h"
> >  #include "qemu/option.h"
> >  #include "sysemu/sysemu.h"
> > @@ -448,23 +447,25 @@ opts_init(smbios_register_config);
> >   */
> >  #define SMBIOS_21_MAX_TABLES_LEN 0xffff
> >
> > -static void smbios_check_type4_count(uint32_t expected_t4_count)
> > +static bool smbios_check_type4_count(uint32_t expected_t4_count, Error **errp)
> >  {
> >      if (smbios_type4_count && smbios_type4_count != expected_t4_count) {
> > -        error_report("Expected %d SMBIOS Type 4 tables, got %d instead",
> > -                     expected_t4_count, smbios_type4_count);
> > -        exit(1);
> > +        error_setg(errp, "Expected %d SMBIOS Type 4 tables, got %d instead",
> > +                   expected_t4_count, smbios_type4_count);
> > +        return false;
> >      }
> > +    return true;
> >  }
> >
> > -void smbios_validate_table(void)
> > +bool smbios_validate_table(Error **errp)
> >  {
> >      if (smbios_ep_type == SMBIOS_ENTRY_POINT_TYPE_32 &&
> >          smbios_tables_len > SMBIOS_21_MAX_TABLES_LEN) {
> > -        error_report("SMBIOS 2.1 table length %zu exceeds %d",
> > -                     smbios_tables_len, SMBIOS_21_MAX_TABLES_LEN);
> > -        exit(1);
> > +        error_setg(errp, "SMBIOS 2.1 table length %zu exceeds %d",
> > +                   smbios_tables_len, SMBIOS_21_MAX_TABLES_LEN);
> > +        return false;
> >      }
> > +    return true;
> >  }
> >
> >  bool smbios_skip_table(uint8_t type, bool required_table)
> > @@ -1027,15 +1028,18 @@ void smbios_get_tables(MachineState *ms,
> >      smbios_build_type_41_table(errp);
> >      smbios_build_type_127_table();
> >
> > -    smbios_check_type4_count(ms->smp.sockets);
> > -    smbios_validate_table();
> > +    if (!smbios_check_type4_count(ms->smp.sockets, errp)) {  
> 
> nit: I would do a gfree(smbios_tables) here ..
> 
> > +        goto err_exit;
> > +    }
> > +    if (!smbios_validate_table(errp)) {
> > +        goto err_exit;  
> 
> and here. Then in err_exit ...
> 

the whole point of err_exit is to do error patch clean up
in one place to avoid duplicate the work.

> > +    }
> >      smbios_entry_point_setup();
> >
> >      /* return tables blob and entry point (anchor), and their sizes */
> >      *tables = smbios_tables;
> >      *tables_len = smbios_tables_len;
> >      *anchor = (uint8_t *)&ep;
> > -
> >      /* calculate length based on anchor string */
> >      if (!strncmp((char *)&ep, "_SM_", 4)) {
> >          *anchor_len = sizeof(struct smbios_21_entry_point);
> > @@ -1044,6 +1048,10 @@ void smbios_get_tables(MachineState *ms,
> >      } else {
> >          abort();
> >      }
> > +
> > +    return;
> > +err_exit:  
> 
> I would add a return here.
> 
> That way all paths explicitly return void.
> 
> > +    g_free(smbios_tables);  
> 
> No return here?

technically there is no need for at the end,
but I can fix it up for clarity.

> 
> 
> >  }
> >
> >  static void save_opt(const char **dest, QemuOpts *opts, const char *name)
> > diff --git a/hw/smbios/smbios_legacy.c b/hw/smbios/smbios_legacy.c
> > index 21f143e738..a6544bf55a 100644
> > --- a/hw/smbios/smbios_legacy.c
> > +++ b/hw/smbios/smbios_legacy.c
> > @@ -19,7 +19,7 @@
> >  #include "qemu/bswap.h"
> >  #include "hw/firmware/smbios.h"
> >  #include "sysemu/sysemu.h"
> > -#include "qemu/error-report.h"
> > +#include "qapi/error.h"
> >
> >  struct smbios_header {
> >      uint16_t length;
> > @@ -128,7 +128,7 @@ static void smbios_build_type_1_fields(void)
> >      }
> >  }
> >
> > -uint8_t *smbios_get_table_legacy(size_t *length)
> > +uint8_t *smbios_get_table_legacy(size_t *length, Error **errp)
> >  {
> >      int i;
> >      size_t usr_offset;
> > @@ -136,15 +136,15 @@ uint8_t *smbios_get_table_legacy(size_t *length)
> >      /* complain if fields were given for types > 1 */
> >      if (find_next_bit(smbios_have_fields_bitmap,
> >                        SMBIOS_MAX_TYPE + 1, 2) < SMBIOS_MAX_TYPE + 1) {
> > -        error_report("can't process fields for smbios "
> > +        error_setg(errp, "can't process fields for smbios "
> >                       "types > 1 on machine versions < 2.1!");
> > -        exit(1);
> > +        goto err_exit;
> >      }
> >
> >      if (test_bit(4, smbios_have_binfile_bitmap)) {
> > -        error_report("can't process table for smbios "
> > -                     "type 4 on machine versions < 2.1!");
> > -        exit(1);
> > +        error_setg(errp, "can't process table for smbios "
> > +                   "type 4 on machine versions < 2.1!");
> > +        goto err_exit;
> >      }
> >
> >      g_free(smbios_entries);
> > @@ -173,7 +173,13 @@ uint8_t *smbios_get_table_legacy(size_t *length)
> >
> >      smbios_build_type_0_fields();
> >      smbios_build_type_1_fields();
> > -    smbios_validate_table();
> > +    if (!smbios_validate_table(errp)) {
> > +        goto err_exit;
> > +    }
> > +
> >      *length = smbios_entries_len;
> >      return smbios_entries;
> > +err_exit:
> > +    g_free(smbios_entries);
> > +    return NULL;
> >  }
> > --
> > 2.39.3
> >
> >  
>