[Intel-gfx] [PATCH 5/5] drm/i915/uc: Reject doplicate entries in firmware table

[John Harrison]

On 4/19/2023 10:02, John Harrison wrote:
> On 4/18/2023 16:24, Ceraolo Spurio, Daniele wrote:
>> Typo doplicate in patch title
>>
>> On 4/14/2023 5:57 PM, John.C.Harrison at Intel.com wrote:
>>> From: John Harrison <John.C.Harrison at Intel.com>
>>>
>>> It was noticed that duplicte entries in the firmware table could cause
>>
>> typo duplicte
>>
>>> an infinite loop in the firmware loading code if that entry failed to
>>> load. Duplicate entries are a bug anyway and so should never happen.
>>> Ensure they don't by tweaking the table validation code to reject
>>> duplicates.
>>
>> Here you're not really rejecting anything though, just printing an 
>> error (and even that only if the SELFTEST kconfig is selected). This 
>> would allow our CI to catch issues with patches sent to our ML, but 
>> IIRC the reported bug was on a kernel fork. We could disable the FW 
>> loading is the table for that particular blob type is in an invalid 
>> state, as it wouldn't be safe to attempt a load in that case anyway.
> The validation code is rejecting duplicates. Whether the driver loads 
> or not after a failed validation is another matter.
>
> I was basically assuming that CI will fail on the error message and 
> thus prevent such code ever being merged. But yeah, I guess we don't 
> run CI on backports to stable kernels and such. Although, I would hope 
> that anyone pushing patches to a stable kernel would run some testing 
> on it first!
>
> Any thoughts on a good way to fail the load? We don't want to just 
> pretend that firmware is not wanted/required on the platform and just 
> load the i915 module without the firmware. Also, what about the longer 
> plan of moving the validation to a selftest. You can't fail the load 
> at all then.
Actually, forgot we already have a INTEL_UC_FIRMWARE_ERROR status. That 
works fine for aborting the load. So just go with that and drop the plan 
to move to a selftest?

John.


>
> John.
>
>>
>>>
>>> For full m/m/p files, that can be done by simply tweaking the patch
>>> level check to reject matching values. For reduced version entries,
>>> the filename itself must be compared.
>>>
>>> Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 27 
>>> +++++++++++++++++++++---
>>>   1 file changed, 24 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c 
>>> b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>>> index c589782467265..44829247ef6bc 100644
>>> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>>> @@ -319,7 +319,7 @@ static void validate_fw_table_type(struct 
>>> drm_i915_private *i915, enum intel_uc_
>>>   {
>>>       const struct uc_fw_platform_requirement *fw_blobs;
>>>       u32 fw_count;
>>> -    int i;
>>> +    int i, j;
>>>         if (type >= ARRAY_SIZE(blobs_all)) {
>>>           drm_err(&i915->drm, "No blob array for %s\n", 
>>> intel_uc_fw_type_repr(type));
>>> @@ -334,6 +334,27 @@ static void validate_fw_table_type(struct 
>>> drm_i915_private *i915, enum intel_uc_
>>>         /* make sure the list is ordered as expected */
>>>       for (i = 1; i < fw_count; i++) {
>>> +        /* Versionless file names must be unique per platform: */
>>> +        for (j = i + 1; j < fw_count; j++) {
>>> +            /* Same platform? */
>>> +            if (fw_blobs[i].p != fw_blobs[j].p)
>>> +                continue;
>>> +
>>> +            if (fw_blobs[i].blob.path != fw_blobs[j].blob.path)
>>> +                continue;
>>> +
>>> +            drm_err(&i915->drm, "Diplicaate %s blobs: %s r%u 
>>> %s%d.%d.%d [%s] matches %s r%u %s%d.%d.%d [%s]\n",
>>
>> Typo Diplicaate
>>
>> Daniele
>>
>>> + intel_uc_fw_type_repr(type),
>>> +                intel_platform_name(fw_blobs[j].p), fw_blobs[j].rev,
>>> +                fw_blobs[j].blob.legacy ? "L" : "v",
>>> +                fw_blobs[j].blob.major, fw_blobs[j].blob.minor,
>>> +                fw_blobs[j].blob.patch, fw_blobs[j].blob.path,
>>> +                intel_platform_name(fw_blobs[i].p), fw_blobs[i].rev,
>>> +                fw_blobs[i].blob.legacy ? "L" : "v",
>>> +                fw_blobs[i].blob.major, fw_blobs[i].blob.minor,
>>> +                fw_blobs[i].blob.patch, fw_blobs[i].blob.path);
>>> +        }
>>> +
>>>           /* Next platform is good: */
>>>           if (fw_blobs[i].p < fw_blobs[i - 1].p)
>>>               continue;
>>> @@ -377,8 +398,8 @@ static void validate_fw_table_type(struct 
>>> drm_i915_private *i915, enum intel_uc_
>>>           if (fw_blobs[i].blob.minor != fw_blobs[i - 1].blob.minor)
>>>               goto bad;
>>>   -        /* Patch versions must be in order: */
>>> -        if (fw_blobs[i].blob.patch <= fw_blobs[i - 1].blob.patch)
>>> +        /* Patch versions must be in order and unique: */
>>> +        if (fw_blobs[i].blob.patch < fw_blobs[i - 1].blob.patch)
>>>               continue;
>>>     bad:
>>
>