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

[John Harrison]

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.

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:
>