Re: [PATCH] drm/xe/vf: Reset VF GuC state on fini

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 1/22/2026 10:34 PM, Daniele Ceraolo Spurio wrote:
> 
> 
> On 1/22/2026 7:19 AM, Michal Wajdeczko wrote:
>> Unlike native/PF driver, which was explicitly triggering full GuC
>> reset during driver unwind, the VF driver was not notifying GuC that
>> it is about to unwind, and this could lead GuC to access stale data,
>> which in turn could be interpreted as VF's malicious activity.
>>
>> Add managed action to send to GuC VF_RESET message during GT unwind.
>>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
>> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_guc.c | 11 +++++++++++
>>   1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
>> index 44360437beeb..2efc4678fa73 100644
>> --- a/drivers/gpu/drm/xe/xe_guc.c
>> +++ b/drivers/gpu/drm/xe/xe_guc.c
>> @@ -668,6 +668,13 @@ static void guc_fini_hw(void *arg)
>>       guc_g2g_fini(guc);
>>   }
>>   +static void vf_guc_fini_hw(void *arg)
>> +{
>> +    struct xe_guc *guc = arg;
>> +
>> +    xe_gt_sriov_vf_reset(guc_to_gt(guc));
>> +}
>> +
>>   /**
>>    * xe_guc_comm_init_early - early initialization of GuC communication
>>    * @guc: the &xe_guc to initialize
>> @@ -772,6 +779,10 @@ int xe_guc_init(struct xe_guc *guc)
>>           xe->info.has_page_reclaim_hw_assist = false;
>>         if (IS_SRIOV_VF(xe)) {
>> +        ret = devm_add_action_or_reset(xe->drm.dev, vf_guc_fini_hw, guc);
>> +        if (ret)
>> +            goto out;
>> +
> 
> it kind of feels weird to have this before the ct_init, but it doesn't really matter, so:

this is on purpose, as on the unwind this RESET action will be called _after_ any devm action that CT could register in the future
(like CONTROL_CTB=disable, which won't be accepted by the GuC if we send earlier RESET without a NEGOTIATE_ABI call)

> 
> Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

thanks!

> 
> Daniele
> 
>>           ret = xe_guc_ct_init(&guc->ct);
>>           if (ret)
>>               goto out;
>