Re: [PATCH] [next] i915/gvt: remove hardcoded value on crc32_start calculation

From: Zhenyu Wang
Date: Tue Nov 08 2022 - 01:44:45 EST


On 2022.10.30 16:36:28 +1300, Paulo Miguel Almeida wrote:
> struct gvt_firmware_header has a crc32 member in which all members that
> come after the that field are used to calculate it. The previous
> implementation added the value '4' (crc32's u32 size) to calculate the
> crc32_start offset which came across as a bit cryptic until you take a
> deeper look at the struct.
>
> This patch changes crc32_start offset to the 'version' member which is
> the first member of the struct gvt_firmware_header after crc32.
>
> It's worth mentioning that doing a build before/after this patch results
> in no binary output differences.
>
> Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gvt/firmware.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/firmware.c b/drivers/gpu/drm/i915/gvt/firmware.c
> index 54fe442238c6..a683c22d5b64 100644
> --- a/drivers/gpu/drm/i915/gvt/firmware.c
> +++ b/drivers/gpu/drm/i915/gvt/firmware.c
> @@ -104,7 +104,7 @@ static int expose_firmware_sysfs(struct intel_gvt *gvt)
>
> memcpy(p, gvt->firmware.mmio, info->mmio_size);
>
> - crc32_start = offsetof(struct gvt_firmware_header, crc32) + 4;
> + crc32_start = offsetof(struct gvt_firmware_header, version);
> h->crc32 = crc32_le(0, firmware + crc32_start, size - crc32_start);
>
> firmware_attr.size = size;
> --
> 2.25.4
>

Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>

thanks!

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