From: Yi Liu <yi.l.liu@intel.com>
To: "Tian, Kevin" <kevin.tian@intel.com>, Jason Gunthorpe <jgg@nvidia.com>
Cc: "baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>
Subject: Re: [RFC] iommufd: Use accurate dev_id in the PRI forwarding path
Date: Thu, 6 Mar 2025 13:01:30 +0800 [thread overview]
Message-ID: <f66eba4a-7de1-47ca-bf9e-22ad30b53418@intel.com> (raw)
In-Reply-To: <BN9PR11MB52760A7D6D2A5680A3DC240C8CCA2@BN9PR11MB5276.namprd11.prod.outlook.com>
On 2025/3/6 12:10, Tian, Kevin wrote:
>> From: Liu, Yi L <yi.l.liu@intel.com>
>> Sent: Thursday, March 6, 2025 11:30 AM
>>
>> On 2025/3/6 11:10, Tian, Kevin wrote:
>>>> From: Jason Gunthorpe <jgg@nvidia.com>
>>>> Sent: Thursday, March 6, 2025 1:19 AM
>>>>
>>>> I'm confused about how that can even work if the RID is erased in the
>>>> fabric, how do we deliver the PRI response to the correct entity?
>>>>
>>
>> If the RID is detached, kernel should response any pending PRIs. If user
>> sends a response, it won't suit any pending PRI then dropped.
>>
>
> Jason talked about the case where the iommu group is created e.g
> for a legacy PCI bridge, with all devices behind sharing a same RID.
> Then there is no way to know which device should receive the response.
hmmm. such devices shall not support PRI I suppose. But yes, this also
pushes us to not supporting PRI for devices that have alias. We might
need an iommu API to count the device number of a given iommu group.
--
Regards,
Yi Liu
next prev parent reply other threads:[~2025-03-06 4:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-05 13:03 [RFC] iommufd: Use accurate dev_id in the PRI forwarding path Yi Liu
2025-03-05 17:18 ` Jason Gunthorpe
2025-03-06 3:10 ` Tian, Kevin
2025-03-06 3:19 ` Baolu Lu
2025-03-06 3:30 ` Yi Liu
2025-03-06 4:10 ` Tian, Kevin
2025-03-06 4:55 ` Baolu Lu
2025-03-06 5:01 ` Yi Liu [this message]
2025-03-06 12:13 ` Jason Gunthorpe
2025-03-06 7:09 ` Yi Liu
2025-03-06 19:06 ` Jason Gunthorpe
2025-03-07 1:32 ` Baolu Lu
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