Re: [PATCH v3 2/3] drm/i915/opregion: rvda is relative from opregion base in opregion 2.1+

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 08 Feb 2019, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Fri, Feb 08, 2019 at 08:42:53PM +0200, Jani Nikula wrote:
>> Starting from opregion version 2.1 (roughly corresponding to ICL+) the
>> RVDA field is relative from the beginning of opregion, not absolute
>> address.
>> 
>> Fix the error path while at it.
>> 
>> v2: Make relative vs. absolute conditional on the opregion version,
>>     bumped for the purpose. Turned out there are machines relying on
>>     absolute RVDA in the wild.
>> 
>> v3: Fix the version checks
>> 
>> Fixes: 04ebaadb9f2d ("drm/i915/opregion: handle VBT sizes bigger than 6 KB")
>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Cc: Imre Deak <imre.deak@intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_opregion.c | 24 +++++++++++++++++++++---
>>  1 file changed, 21 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
>> index f1b841580521..5e00ee9270b5 100644
>> --- a/drivers/gpu/drm/i915/intel_opregion.c
>> +++ b/drivers/gpu/drm/i915/intel_opregion.c
>> @@ -123,7 +123,8 @@ struct opregion_asle {
>>  	u64 fdss;
>>  	u32 fdsp;
>>  	u32 stat;
>> -	u64 rvda;	/* Physical address of raw vbt data */
>> +	u64 rvda;	/* Physical (2.0) or relative from opregion (2.1+)
>> +			 * address of raw VBT data. */
>>  	u32 rvds;	/* Size of raw vbt data */
>>  	u8 rsvd[58];
>>  } __packed;
>> @@ -964,9 +965,24 @@ int intel_opregion_setup(struct drm_i915_private *dev_priv)
>>  
>>  	if (opregion->header->over.major >= 2 && opregion->asle &&

Push this line to short term memory.

>>  	    opregion->asle->rvda && opregion->asle->rvds) {
>> -		opregion->rvda = memremap(opregion->asle->rvda,
>> -					  opregion->asle->rvds,
>> +		resource_size_t rvda = opregion->asle->rvda;
>> +
>> +		/*
>> +		 * opregion 2.0: rvda is the physical VBT address.
>> +		 *
>> +		 * opregion 2.1+: rvda is unsigned, relative offset from
>> +		 * opregion base, and should never point within opregion.
>> +		 */
>> +		if (opregion->header->over.major > 2 ||
>> +		    opregion->header->over.minor >= 1) {
>
> What happens with version 1.1?

Pop. ;)

BR,
Jani.

>
>> +			WARN_ON(rvda < OPREGION_SIZE);
>> +
>> +			rvda += asls;
>> +		}
>> +
>> +		opregion->rvda = memremap(rvda, opregion->asle->rvds,
>>  					  MEMREMAP_WB);
>> +
>>  		vbt = opregion->rvda;
>>  		vbt_size = opregion->asle->rvds;
>>  		if (intel_bios_is_valid_vbt(vbt, vbt_size)) {
>> @@ -976,6 +992,8 @@ int intel_opregion_setup(struct drm_i915_private *dev_priv)
>>  			goto out;
>>  		} else {
>>  			DRM_DEBUG_KMS("Invalid VBT in ACPI OpRegion (RVDA)\n");
>> +			memunmap(opregion->rvda);
>> +			opregion->rvda = NULL;
>>  		}
>>  	}
>>  
>> -- 
>> 2.20.1

-- 
Jani Nikula, Intel Open Source Graphics Center
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