From: Baolu Lu <baolu.lu@linux.intel.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>
Cc: baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] iommu/vt-d: Enable PASID during iommu device probe
Date: Tue, 13 Sep 2022 17:25:00 +0800 [thread overview]
Message-ID: <826a10fa-7dc3-887d-8a08-e03dcf1fa59c@linux.intel.com> (raw)
In-Reply-To: <BN9PR11MB52766A868879689D55AE9DC68C479@BN9PR11MB5276.namprd11.prod.outlook.com>
On 2022/9/13 16:01, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Monday, September 12, 2022 10:48 AM
>>
>> @@ -1401,7 +1403,6 @@ static void iommu_enable_dev_iotlb(struct
>> device_domain_info *info)
>
> This is not the right name now as dev_iotlb is only related to ATS.
Yes. This name is confusing. Perhaps we can split it into some specific
helpers,
- intel_iommu_enable_pci_ats()
- intel_iommu_enabel_pci_pri()
- intel_iommu_enable_pci_pasid()
?
>
>> info->pfsid = pci_dev_id(pf_pdev);
>> }
>>
>> -#ifdef CONFIG_INTEL_IOMMU_SVM
>> /* The PCIe spec, in its wisdom, declares that the behaviour of
>> the device if you enable PASID support after ATS support is
>> undefined. So always enable PASID support on devices which
>> @@ -1414,7 +1415,7 @@ static void iommu_enable_dev_iotlb(struct
>> device_domain_info *info)
>> (info->pasid_enabled ? pci_prg_resp_pasid_required(pdev) : 1)
>> &&
>> !pci_reset_pri(pdev) && !pci_enable_pri(pdev, PRQ_DEPTH))
>> info->pri_enabled = 1;
>> -#endif
>> +
>> if (info->ats_supported && pci_ats_page_aligned(pdev) &&
>> !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {
>> info->ats_enabled = 1;
>
> iommu_enable_dev_iotlb() is currently called both when the device is probed
> and when sva is enabled (which is actually useless). From this angle the commit
> msg is inaccurate.
The logic is a bit tricky. iommu_support_dev_iotlb() only returns a
devinfo pointer when ATS is supported on the device. So, you are right
if device supports both ATS and PASID; otherwise PASID will not be
enabled.
>
>> diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
>> index 39a06d245f12..b3f40375f214 100644
>> --- a/drivers/iommu/intel/Kconfig
>> +++ b/drivers/iommu/intel/Kconfig
>> @@ -21,6 +21,8 @@ config INTEL_IOMMU
>> select IOASID
>> select IOMMU_DMA
>> select PCI_ATS
>> + select PCI_PRI
>> + select PCI_PASID
>> help
>> DMA remapping (DMAR) devices support enables independent
>> address
>> translations for Direct Memory Access (DMA) from devices.
>> @@ -48,8 +50,6 @@ config INTEL_IOMMU_DEBUGFS
>> config INTEL_IOMMU_SVM
>> bool "Support for Shared Virtual Memory with Intel IOMMU"
>> depends on X86_64
>> - select PCI_PASID
>> - select PCI_PRI
>> select MMU_NOTIFIER
>> select IOASID
>
> this is already selected by CONFIG_INTEL_IOMMU
Yes. Should be removed.
>
>> select IOMMU_SVA
>> --
>> 2.25.1
>
>
Best regards,
baolu
next prev parent reply other threads:[~2022-09-13 9:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 2:48 [PATCH 1/1] iommu/vt-d: Enable PASID during iommu device probe Lu Baolu
2022-09-13 3:13 ` Tian, Kevin
2022-09-13 6:01 ` Baolu Lu
2022-09-13 7:42 ` Tian, Kevin
2022-09-13 7:46 ` Ethan Zhao
2022-09-13 9:30 ` Baolu Lu
[not found] ` <e26efaee-d84a-3b60-8400-90d8e49a9b25@linux.intel.com>
2022-09-15 3:00 ` Baolu Lu
2022-09-16 2:40 ` Ethan Zhao
2022-09-16 3:05 ` Baolu Lu
2022-09-16 3:37 ` Ethan Zhao
[not found] ` <a6ac5953-7372-9894-58d4-d1ee2905d4dd@linux.intel.com>
2022-09-16 4:01 ` Baolu Lu
2022-09-13 8:01 ` Tian, Kevin
2022-09-13 9:25 ` Baolu Lu [this message]
2022-09-15 3:22 ` Tian, Kevin
2022-09-15 7:21 ` Baolu Lu
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