Re: [PATCH v2 2/5] OvmfPkg/EmuVariableFvbRuntimeDxe: change block size to 4KB

[Laszlo Ersek <lersek@redhat.com>]

On 05/18/17 22:56, Jordan Justen wrote:
> On 2017-05-18 12:40:30, Laszlo Ersek wrote:
>> On 05/18/17 20:49, Jordan Justen wrote:
>>> On 2017-05-18 08:14:33, Laszlo Ersek wrote:
>>>> diff --git a/OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.h b/OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.h
>>>> index 4247d21d72f8..beb11e3f9a90 100644
>>>> --- a/OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.h
>>>> +++ b/OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.h
>>>> @@ -58,8 +58,14 @@ typedef struct {
>>>>  //
>>>>  // Constants
>>>>  //
>>>> -#define EMU_FVB_BLOCK_SIZE (FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize))
>>>> -#define EMU_FVB_SIZE (2 * FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize))
>>>> +#define EMU_FVB_BLOCK_SIZE \
>>>> +  EFI_PAGE_SIZE
>>>> +#define EMU_FVB_NUM_SPARE_BLOCKS \
>>>> +  EFI_SIZE_TO_PAGES ((UINTN)FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize))
>>>> +#define EMU_FVB_NUM_TOTAL_BLOCKS \
>>>> +  (2 * EMU_FVB_NUM_SPARE_BLOCKS)
>>>> +#define EMU_FVB_SIZE \
>>>> +  (EMU_FVB_NUM_TOTAL_BLOCKS * EMU_FVB_BLOCK_SIZE)
>>>>  #define FTW_WRITE_QUEUE_SIZE \
>>>>    (FixedPcdGet32 (PcdFlashNvStorageFtwWorkingSize) - \
>>>>     sizeof (EFI_FAULT_TOLERANT_WORKING_BLOCK_HEADER))
>>>
>>> In the cases where we don't exceed 80 columns, I don't see the excess
>>> newlines as helping here, style-wise.
>>
>> My first preference would have been
>>
>> #define SHORT_MACRO_NAME           replacement text 1
>> #define ANNOYINGLY_LONG_MACRO_NAME replacement text 2
>>
>> That is, to keep both the macro names and the replacement texts aligned.
>> However, that way I wouldn't fit into 80 chars on some lines, and then
>> breaking only *some* macro definitions to multiple lines looked
>> horrible. Which is why I opted for the current layout: it is uniform,
>> and it does preserve the alignment for both macro names and replacement
>> texts separately.
> 
> I don't think you would make a block of function calls all multiline
> if one call required it. I see your point and I agree that aligning
> things can be nice if it works out. It seems like it doesn't in this
> case.
> 
> Could FTW_SPARE_SIZE and FTW_WORKING_SIZE macros help?

Assuming you mean those as shorthands for the FixedPcdGet32() macro
invocations, they wouldn't (fully); FTW_WRITE_QUEUE_SIZE would remain
overlong even after such a replacement.

> 
> If you feel strongly about this current format, then keep it, as I
> don't feel too strongly about it.

I don't feel strongly about this layout, so if (when) you have an
incremental patch, I'll be glad to review it. What I do feel strongly
about :) is not wanting to retest the -bios scenarios, which is sort of
required once these macros are touched. (The ASSERT() below is a lot
easier / quicker to test.) Due to the testing impact, I prefer to keep
the current layout.

> 
>>>
>>> Could you add to the entry-point an assert:
>>>
>>>   ASSERT(FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize) %
>>>          EMU_FVB_BLOCK_SIZE == 0);
>>
>> Should I squash that into this patch?
> 
> Yeah. No need for resend.

Thanks, I'll squash it then.

Cheers,
Laszlo