Re: [PATCH v3 01/11] gpu: nova-core: vbios: fix various cases of reading past `BIOS_MAX_SCAN_LEN`

Joel Fernandes
2026-04-29T14:32:48Z

On 4/29/2026 9:24 AM, Alexandre Courbot wrote:
> On Tue Apr 21, 2026 at 5:20 PM JST, Eliot Courtney wrote:
>> Fix various cases that allow reading past `BIOS_MAX_SCAN_LEN` when
>> scanning the VBIOS.
>>
>> Fix bug where `read_more_at_offset` would unnecessarily read more data.
>> This happens when the window to read has some part cached and some part
>> not. It would read `len` bytes instead of just the uncached portion,
>> which could read past `BIOS_MAX_SCAN_LEN`.
>>
>> Also add more checked arithmetic to catch potential overflows.
>> `read_bios_image_at_offset` is called with a length from the VBIOS
>> header, so we should be more defensive here.
>
> This reads like this patch is doing 3 different things, or at least two,
> since the second chunk (`read_bios_image_at_offset`) does not seem
> related to `BIOS_MAX_SCAN_LEN`.
>
> The general rule is that one patch should do one thing - the trick here
> will be to either update the message to describe a larger thing (and not
> 3 small ones), or to split the patch. Both are acceptable IMHO.

I thought about that too but didn't say it because it seemed the other
changes were just 2-3 lines and generally same 'functional area'. However,
I agree with Alex, perhaps splitting into 1 for BIOS_MAX_SCAN_LEN and
another for checked_add makes sense.

>
>>
>> Fixes: 6fda04e7f0cd ("gpu: nova-core: vbios: Add base support for VBIOS construction and iteration")
>> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Feel free to still carry my tag either way.

Thanks.