Re: [PATCH v2 1/2] hw/i386/pc: pc_system_ovmf_table_find: Assert that flash was parsed

[Philippe Mathieu-Daudé]

On 6/30/21 3:38 PM, Tom Lendacky wrote:
> On 6/30/21 12:46 AM, Dov Murik wrote:
>> Add assertion in pc_system_ovmf_table_find that verifies that the flash
>> was indeed previously parsed (looking for the OVMF table) by
>> pc_system_parse_ovmf_flash.
>>
>> Now pc_system_ovmf_table_find distinguishes between "no one called
>> pc_system_parse_ovmf_flash" (which will abort due to assertion failure)
>> and "the flash was parsed but no OVMF table was found, or it is invalid"
>> (which will return false).
>>
>> Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
> 
> Does the qemu coding style prefer not initializing the bool to false since
> it will default to that?

Indeed, you are right, and checkpatch will block this patch:

ERROR: do not initialise statics to 0 or NULL
#33: FILE: hw/i386/pc_sysfw.c:129:
+static bool ovmf_flash_parsed = false;

total: 1 errors, 0 warnings, 28 lines checked

> Otherwise,
> 
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> 
>> ---
>>  hw/i386/pc_sysfw.c | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
>> index 6ce37a2b05..9eac36b830 100644
>> --- a/hw/i386/pc_sysfw.c
>> +++ b/hw/i386/pc_sysfw.c
>> @@ -126,6 +126,7 @@ void pc_system_flash_cleanup_unused(PCMachineState *pcms)
>>  
>>  #define OVMF_TABLE_FOOTER_GUID "96b582de-1fb2-45f7-baea-a366c55a082d"
>>  
>> +static bool ovmf_flash_parsed = false;
>>  static uint8_t *ovmf_table;
>>  static int ovmf_table_len;
>>  
>> @@ -136,10 +137,12 @@ static void pc_system_parse_ovmf_flash(uint8_t 
>> *flash_ptr, size_t flash_size)
>>      int tot_len;
>>  
>>      /* should only be called once */
>> -    if (ovmf_table) {
>> +    if (ovmf_flash_parsed) {
>>          return;
>>      }
>>  
>> +    ovmf_flash_parsed = true;
>> +
>>      if (flash_size < TARGET_PAGE_SIZE) {
>>          return;
>>      }
>> @@ -183,6 +186,8 @@ bool pc_system_ovmf_table_find(const char *entry, 
>> uint8_t **data,
>>      int tot_len = ovmf_table_len;
>>      QemuUUID entry_guid;
>>  
>> +    assert(ovmf_flash_parsed);
>> +
>>      if (qemu_uuid_parse(entry, &entry_guid) < 0) {
>>          return false;
>>      }
>>
>