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

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

[Paulo Miguel Almeida]

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@gmail.com>
---
 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

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

[Zhenyu Wang]

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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@gmail.com>
> ---
>  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@linux.intel.com>

thanks!

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