Re: [Qemu-devel] Re: [PATCH] Correct SMBIOS handling of multiple tables

[Alex Williamson]

On Thu, 2009-05-28 at 11:05 -0400, Beth Kon wrote:
> This leads to the question of whether qemu should verify that 
> command-line smbios tables make "sense" (e.g. number of type 4 tables == 
> smp_cpus).  The SMBIOS spec has many cases where multiples of a table 
> are required. Covering all of them would be very burdensome with little 
> or no payback. But I think it is worth putting in a check for table 4, 
> since it is relatively simple and is pretty likely to be specified on 
> the command line.

I think that makes sense, we can add other checks as needed.

> One other nit I fixed was detection of a bad filename.
> 
> So if you agree, I'd like to submit your rombios32.c patch along with my 
> table 4 check patch (combined here for simplicity).

Patch comment below....

> diff --git a/hw/smbios.c b/hw/smbios.c
> index ced90ce..a8b52c7 100644
> --- a/hw/smbios.c
> +++ b/hw/smbios.c
> @@ -173,8 +173,8 @@ int smbios_entry_add(const char *t)
>          struct smbios_table *table;
>          int size = get_image_size(buf);
>  
> -        if (size < sizeof(struct smbios_structure_header)) {
> -            fprintf(stderr, "Cannot read smbios file %s", buf);
> +        if (size == -1 || size < sizeof(struct
> smbios_structure_header)) {
> +            fprintf(stderr, "Cannot read smbios file %s\n", buf);
>              exit(1);
>          }
>  
> @@ -196,6 +196,9 @@ int smbios_entry_add(const char *t)
>  
>          header = (struct smbios_structure_header *)(table->data);
>          smbios_check_collision(header->type, SMBIOS_TABLE_ENTRY);
> +        if (header->type == 4) {
> +            smbios_type4_count++;
> +        }
>  
>          smbios_entries_len += sizeof(*table) + size;
>          (*(uint16_t *)smbios_entries) =
> diff --git a/kvm/bios/rombios32.c b/kvm/bios/rombios32.c
> index cbd5f15..f3e75f8 100755
> --- a/kvm/bios/rombios32.c
> +++ b/kvm/bios/rombios32.c
> @@ -2531,13 +2531,14 @@ smbios_load_external(int type, char **p,
> unsigned *nr_structs,
>              *max_struct_size = *p - (char *)header;
>      }
>  
> -    /* Mark that we've reported on this type */
> -    used_bitmap[(type >> 6) & 0x3] |= (1ULL << (type & 0x3f));
> +    if (start != *p) {
> +        /* Mark that we've reported on this type */
> +        used_bitmap[(type >> 6) & 0x3] |= (1ULL << (type & 0x3f));
> +        return 1;
> +    }
>  
> -    return (start != *p);
> -#else /* !BX_QEMU */
> +#endif /* !BX_QEMU */
>      return 0;
> -#endif
>  }
>  
>  void smbios_init(void)
> diff --git a/pc-bios/bios.bin b/pc-bios/bios.bin
> index 70bd7ad..50d5365 100644
> Binary files a/pc-bios/bios.bin and b/pc-bios/bios.bin differ
> diff --git a/sysemu.h b/sysemu.h
> index 47d001e..0b982ed 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -115,6 +115,7 @@ extern int rtc_td_hack;
>  extern int alt_grab;
>  extern int usb_enabled;
>  extern int smp_cpus;
> +extern int smbios_type4_count;
>  extern int cursor_hide;
>  extern int graphic_rotate;
>  extern int no_quit;
> diff --git a/vl.c b/vl.c
> index db8265b..c9cc5b7 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -246,6 +246,7 @@ int singlestep = 0;
>  const char *assigned_devices[MAX_DEV_ASSIGN_CMDLINE];
>  int assigned_devices_index;
>  int smp_cpus = 1;
> +int smbios_type4_count = 0;
>  const char *vnc_display;
>  int acpi_enabled = 1;
>  int no_hpet = 0;
> @@ -5775,6 +5776,14 @@ int main(int argc, char **argv, char **envp)
>          }
>      }
>  
> +#ifdef TARGET_I386
> +    if (smbios_type4_count && smbios_type4_count != smp_cpus) {
> +         fprintf(stderr,
> +                 "count of SMBIOS type 4 tables != SMP CPUs
> specified.\n");
> +         exit(1);
> +    }
> +#endif
> +

I'm not thrilled with adding globals and externs in unrelated parts of
the code.  I think we can keep this all internal to smbios.c if we make
a new smbios_validate_table() function that gets called from
smbios_get_table().  Thanks,

Alex