linux-kernel - Re: 答复: 答复: 答复: 答复: 答复: 答复: 答复: [PATCH] iommu/vt-d:Add support for ACPI device in RMRR

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Message-ID: <f631a3b2-5bd4-f48a-5ec5-0fc6118e1c95@linux.intel.com>
Date:   Fri, 7 Aug 2020 16:08:08 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     FelixCui-oc <FelixCui-oc@...oxin.com>,
        Joerg Roedel <joro@...tes.org>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        David Woodhouse <dwmw2@...radead.org>
Cc:     baolu.lu@...ux.intel.com,
        RaymondPang-oc <RaymondPang-oc@...oxin.com>,
        CobeChen-oc <CobeChen-oc@...oxin.com>
Subject: Re: 答复: 答复: 答复: 答复: 答复: 答复: 答复: [PATCH] iommu/vt-d:Add support for ACPI device in RMRR

Hi,

On 2020/8/7 11:29, FelixCui-oc wrote:
> Hi baolu,
> 		I understand what you mean is that you want to put the following processing code in the acpi_device_create_direct_mappings() into the probe_acpi_namespace_devices() ,right?
> 		If you mean it , I think it's OK.

Yes. If the acpi device has companion physical devices, then probe the
companion devices; otherwise, probe the acpi device instead. Also, let's
put detecting and probing acpi devices in different patches so that they
could be easier for reviewing.

Best regards,
baolu

> 
> 	if (pn_dev == NULL) {
> 		acpi_device->bus->iommu_ops = &intel_iommu_ops;
> 		ret = iommu_probe_device(acpi_device);
> 		if (ret) {
> 			pr_err("acpi_device probe fail! ret:%d\n", ret);
> 			return ret;
> 		}
> 		return 0;
> 	}
> 
> Best regards
> Felix cui-oc
> 
> 
> 
> 	
> 
> -----邮件原件-----
> 发件人: Lu Baolu <baolu.lu@...ux.intel.com>
> 发送时间: 2020年8月7日 9:08
> 收件人: FelixCui-oc <FelixCui-oc@...oxin.com>; Joerg Roedel <joro@...tes.org>; iommu@...ts.linux-foundation.org; linux-kernel@...r.kernel.org; David Woodhouse <dwmw2@...radead.org>
> 抄送: baolu.lu@...ux.intel.com; RaymondPang-oc <RaymondPang-oc@...oxin.com>; CobeChen-oc <CobeChen-oc@...oxin.com>
> 主题: Re: 答复: 答复: 答复: 答复: 答复: 答复: [PATCH] iommu/vt-d:Add support for ACPI device in RMRR
> 
> Hi Felix,
> 
> On 2020/8/6 14:51, FelixCui-oc wrote:
>> Hi  baolu,
>> 		>Sure. Before that, let me sync my understanding with you. You have an acpi namespace device in ANDD table, it also shows up in the device scope of a RMRR.
>> 		>Current code doesn't enumerate that device for the RMRR, hence iommu_create_device_direct_mappings() doesn't work for this device.
>>
>> 		>At the same time, probe_acpi_namespace_devices() doesn't work for this device, hence you want to add a home-made
>> 		>acpi_device_create_direct_mappings() helper.
>>
>> 		Your understanding is right.
>> 		But there is a problem that even if the namespace device in rmrr is enumerated in the code, probe_acpi_namespace_devices() also doesn't work for this device.
>> 		This is because the dev parameter of the iommu_create_device_direct_mappings() is not the namespace device in RMRR.
>> 		The actual parameter passed in is the namespace device's physical node device.
>> 		In iommu_create_device_direct_mappings(), the physical node device passed in cannot match the namespace device in rmrr->device[],right?
>> 		We need acpi_device_create_direct_mappings() helper ?
>>
>> 		In addition, adev->physical_node_list is related to the __HID of namespace device reported by the bios.
>> 		For example, if the __HID reported by the bios belongs to acpi_pnp_device_ids[], adev->physical_node_list has no devices.
>> 		So in acpi_device_create_direct_mappings(), I added the case that adev->physical_node_list is empty.
> 
> Got you. Thanks!
> 
> Have you ever tried to have probe_acpi_namespace_devices() handle the case of empty adev->physical_node_list at the same time?
> 
> Best regards,
> baolu
> 
>>
>>
>> Best regards
>> Felix cui
>>
>>
>>    
>>
>> -----邮件原件-----
>> 发件人: Lu Baolu <baolu.lu@...ux.intel.com>
>> 发送时间: 2020年8月6日 10:36
>> 收件人: FelixCui-oc <FelixCui-oc@...oxin.com>; Joerg Roedel
>> <joro@...tes.org>; iommu@...ts.linux-foundation.org;
>> linux-kernel@...r.kernel.org; David Woodhouse <dwmw2@...radead.org>
>> 抄送: baolu.lu@...ux.intel.com; RaymondPang-oc
>> <RaymondPang-oc@...oxin.com>; CobeChen-oc <CobeChen-oc@...oxin.com>
>> 主题: Re: 答复: 答复: 答复: 答复: 答复: [PATCH] iommu/vt-d:Add support for ACPI
>> device in RMRR
>>
>> Hi Felix,
>>
>> On 8/5/20 3:37 PM, FelixCui-oc wrote:
>>> Hi baolu,
>>> 		Let me talk about why acpi_device_create_direct_mappings() is needed and please tell me if there is an error.
>>
>> Sure. Before that, let me sync my understanding with you. You have an acpi namespace device in ANDD table, it also shows up in the device scope of a RMRR. Current code doesn't enumerate that device for the RMRR, hence iommu_create_device_direct_mappings() doesn't work for this device.
>>
>> At the same time, probe_acpi_namespace_devices() doesn't work for this
>> device, hence you want to add a home-made
>> acpi_device_create_direct_mappings() helper.
>>
>> Did I get it right?
>>
>>> 		In the probe_acpi_namespace_devices() function, only the device in the addev->physical_node_list is probed,
>>> 		but we need to establish identity mapping for the namespace device in RMRR. These are two different devices.
>>
>> The namespace device has been probed and put in one drhd's device list.
>> Hence, it should be processed by probe_acpi_namespace_devices(). So the question is why there are no devices in addev->physical_node_list?
>>
>>> 		Therefore, the namespace device in RMRR is not mapped in probe_acpi_namespace_devices().
>>> 		acpi_device_create_direct_mappings() is to create direct mappings for namespace devices in RMRR.
>>
>> Best regards,
>> baolu
>>