Re: [PATCH] drm/amdgpu: Align serial size in drm_amdgpu_info_vbios

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[AMD Public Use]


The point of having the device ID in the structure is because we are reading it from the VBIOS header, not the asic registers. They should match, but an user may flash a VBIOS for a different devid and they may not match.

Regarding sysfs vs ioctl I see value in providing it in both ways, Mesa uses IOCTL and other DRM based tools may benefit as well. I recently went through the trouble of having to add sysfs string parsing for some data not available in ioctl, and while not very complicated, it is a programming inconvenience.

I understand that being uapi, changing it is not easy, but this is information extracted from a VBIOS header, something that has been kept stable for many years.

David

From: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
Sent: Tuesday, May 11, 2021 7:07 AM
To: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Marek Olšák <maraeo@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>; Gu, JiaWei (Will) <JiaWei.Gu@xxxxxxx>; amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Deng, Emily <Emily.Deng@xxxxxxx>; Alex Deucher <alexdeucher@xxxxxxxxx>; Nieto, David M <David.Nieto@xxxxxxx>
Subject: Re: [PATCH] drm/amdgpu: Align serial size in drm_amdgpu_info_vbios
 
Yeah, but umr is making strong use of sysfs as well.

The only justification of this interface would be if we want to use it in Mesa.

And I agree with Marek that looks redundant with the device structure to me as well.

Christian.

Am 11.05.21 um 16:04 schrieb Deucher, Alexander:

[AMD Public Use]


It's being used by umr and some other smi tools to provide vbios information for debugging.

Alex


From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> on behalf of Marek Olšák <maraeo@xxxxxxxxx>
Sent: Tuesday, May 11, 2021 4:18 AM
To: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>; Gu, JiaWei (Will) <JiaWei.Gu@xxxxxxx>; amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Deng, Emily <Emily.Deng@xxxxxxx>; Alex Deucher <alexdeucher@xxxxxxxxx>; Nieto, David M <David.Nieto@xxxxxxx>
Subject: Re: [PATCH] drm/amdgpu: Align serial size in drm_amdgpu_info_vbios
 
Mesa doesn't use sysfs.

Note that this is a uapi, meaning that once it's in the kernel, it can't be changed like that.

What's the use case for this new interface? Isn't it partially redundant with the current device info structure, which seems to have the equivalent of dev_id and rev_id?

Marek

On Tue, May 11, 2021 at 3:51 AM Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote:
Marek and other userspace folks need to decide that.

Basic question here is if Mesa is already accessing sysfs nodes for OpenGL or RADV. If that is the case then we should probably expose the information there as well.

If that isn't the case (which I think it is) then we should implement it as IOCTL.

Regards,
Christian.

Am 10.05.21 um 22:19 schrieb Nieto, David M:

One of the primary usecases is to add this information to the renderer string, I am not sure if there are other cases of UMD drivers accessing sysfs nodes, but I think if we think permissions, if a client is authenticated and opens the render device then it can use the IOCTL, it is unclear to me we can make a such an assumption for sysfs nodes…

 

I think there is value in having both tbh.

 

Regards,

David

 

From: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
Date: Monday, May 10, 2021 at 6:48 AM
To: "Nieto, David M" <David.Nieto@xxxxxxx>, "Gu, JiaWei (Will)" <JiaWei.Gu@xxxxxxx>
Cc: Alex Deucher <alexdeucher@xxxxxxxxx>, "Deng, Emily" <Emily.Deng@xxxxxxx>, Kees Cook <keescook@xxxxxxxxxxxx>, amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [PATCH] drm/amdgpu: Align serial size in drm_amdgpu_info_vbios

 

Well we could add both as sysfs file(s).

Question here is rather what is the primary use case of this and if the application has the necessary access permissions to the sysfs files?

Regards,
Christian.

Am 10.05.21 um 15:42 schrieb Nieto, David M:

Then the application would need to issue the ioctl and then open a sysfs file to get all the information it needs. It makes little sense from a programming perspective to add an incomplete interface in my opinion 

 


From: Gu, JiaWei (Will) <JiaWei.Gu@xxxxxxx>
Sent: Monday, May 10, 2021 12:13:07 AM
To: Nieto, David M <David.Nieto@xxxxxxx>
Cc: Alex Deucher <alexdeucher@xxxxxxxxx>; amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Kees Cook <keescook@xxxxxxxxxxxx>; Deng, Emily <Emily.Deng@xxxxxxx>
Subject: RE: [PATCH] drm/amdgpu: Align serial size in drm_amdgpu_info_vbios

 

[AMD Official Use Only - Internal Distribution Only]

Hi David,

What I meant is to ONLY delete the serial[16] from drm_amdgpu_info_vbios, not the whole struct.

struct drm_amdgpu_info_vbios {
        __u8 name[64];
        __u32 dbdf;
        __u8 vbios_pn[64];
        __u32 version;
        __u8 date[32];
        __u8 serial[16]; // jiawei: shall we delete this
        __u32 dev_id;
        __u32 rev_id;
        __u32 sub_dev_id;
        __u32 sub_ved_id;
};

serial[16] in drm_amdgpu_info_vbios  copied from adev->serial, but there's already a sysfs named serial_number, which exposes it already.

static ssize_t amdgpu_device_get_serial_number(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct drm_device *ddev = dev_get_drvdata(dev);
        struct amdgpu_device *adev = ddev->dev_private;

        return snprintf(buf, PAGE_SIZE, "%s\n", adev->serial);
}

Thanks,
Jiawei


-----Original Message-----
From: Nieto, David M <David.Nieto@xxxxxxx>
Sent: Monday, May 10, 2021 2:53 PM
To: Gu, JiaWei (Will) <JiaWei.Gu@xxxxxxx>
Cc: Alex Deucher <alexdeucher@xxxxxxxxx>; amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Kees Cook <keescook@xxxxxxxxxxxx>; Deng, Emily <Emily.Deng@xxxxxxx>
Subject: Re: [PATCH] drm/amdgpu: Align serial size in drm_amdgpu_info_vbios

No, this structure contains all the details of the vbios: date, serial number, name, etc.

The sysfs node only contains the vbios name string

> On May 9, 2021, at 23:33, Gu, JiaWei (Will) <JiaWei.Gu@xxxxxxx> wrote:
>
> [AMD Official Use Only - Internal Distribution Only]
>
> With a second thought,
> __u8 serial[16] in drm_amdgpu_info_vbios is a bit redundant, sysfs serial_number already exposes it.
>
> Is it fine to abandon it from drm_amdgpu_info_vbios struct? @Alex
> Deucher @Nieto, David M
>
> Best regards,
> Jiawei
>
> -----Original Message-----
> From: Alex Deucher <alexdeucher@xxxxxxxxx>
> Sent: Sunday, May 9, 2021 11:59 PM
> To: Gu, JiaWei (Will) <JiaWei.Gu@xxxxxxx>
> Cc: amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Kees Cook
> <keescook@xxxxxxxxxxxx>
> Subject: Re: [PATCH] drm/amdgpu: Align serial size in
> drm_amdgpu_info_vbios
>
>> On Sat, May 8, 2021 at 2:48 AM Jiawei Gu <Jiawei.Gu@xxxxxxx> wrote:
>>
>> 20 should be serial char size now instead of 16.
>>
>> Signed-off-by: Jiawei Gu <Jiawei.Gu@xxxxxxx>
>
> Please make sure this keeps proper 64 bit alignment in the structure.
>
> Alex
>
>
>> ---
>> include/uapi/drm/amdgpu_drm.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/uapi/drm/amdgpu_drm.h
>> b/include/uapi/drm/amdgpu_drm.h index 2b487a8d2727..1c20721f90da
>> 100644
>> --- a/include/uapi/drm/amdgpu_drm.h
>> +++ b/include/uapi/drm/amdgpu_drm.h
>> @@ -957,7 +957,7 @@ struct drm_amdgpu_info_vbios {
>>        __u8 vbios_pn[64];
>>        __u32 version;
>>        __u8 date[32];
>> -       __u8 serial[16];
>> +       __u8 serial[20];
>>        __u32 dev_id;
>>        __u32 rev_id;
>>        __u32 sub_dev_id;
>> --
>> 2.17.1
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>> https://nam11.safelinks.protection.outlook.com/?url="">
>> t
>>
s.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&amp;data=""> >> i
>> awei.Gu%40amd.com%7Ccea31833184c41e8574508d9130360cc%7C3dd8961fe4884e
>> 6
>> 08e11a82d994e183d%7C0%7C0%7C637561727523880356%7CUnknown%7CTWFpbGZsb3
>> d
>> 8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7
>> C
>> 1000&amp;sdata=kAJiC6WoJUTeExwk6ftrLfMoY2OTAwg9X7mGgJT3kLk%3D&amp;res
>> e
>> rved=0



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