[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <40d9b0fa-4a36-c3b7-53bb-4333ff89dc45@linux.intel.com>
Date: Thu, 3 Aug 2023 12:05:37 +0800
From: Baolu Lu <baolu.lu@...ux.intel.com>
To: "Tian, Kevin" <kevin.tian@...el.com>,
"Liu, Yi L" <yi.l.liu@...el.com>,
"joro@...tes.org" <joro@...tes.org>,
"alex.williamson@...hat.com" <alex.williamson@...hat.com>,
"jgg@...dia.com" <jgg@...dia.com>,
"robin.murphy@....com" <robin.murphy@....com>
Cc: baolu.lu@...ux.intel.com, "cohuck@...hat.com" <cohuck@...hat.com>,
"eric.auger@...hat.com" <eric.auger@...hat.com>,
"nicolinc@...dia.com" <nicolinc@...dia.com>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"mjrosato@...ux.ibm.com" <mjrosato@...ux.ibm.com>,
"chao.p.peng@...ux.intel.com" <chao.p.peng@...ux.intel.com>,
"yi.y.sun@...ux.intel.com" <yi.y.sun@...ux.intel.com>,
"peterx@...hat.com" <peterx@...hat.com>,
"jasowang@...hat.com" <jasowang@...hat.com>,
"shameerali.kolothum.thodi@...wei.com"
<shameerali.kolothum.thodi@...wei.com>,
"lulu@...hat.com" <lulu@...hat.com>,
"suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>,
"iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
"Duan, Zhenzhong" <zhenzhong.duan@...el.com>
Subject: Re: [PATCH v4 09/12] iommu/vt-d: Add iotlb flush for nested domain
On 2023/8/3 12:00, Tian, Kevin wrote:
>> From: Baolu Lu <baolu.lu@...ux.intel.com>
>> Sent: Thursday, August 3, 2023 11:25 AM
>>
>> On 2023/8/2 15:46, Tian, Kevin wrote:
>>>> From: Liu, Yi L <yi.l.liu@...el.com>
>>>> Sent: Monday, July 24, 2023 7:14 PM
>>>>
>>>> +
>>>> + spin_lock_irqsave(&dmar_domain->lock, flags);
>>>> + list_for_each_entry(info, &dmar_domain->devices, link)
>>>> + intel_nested_invalidate(info->dev, dmar_domain,
>>>> + req->addr, req->npages);
>>>> + spin_unlock_irqrestore(&dmar_domain->lock, flags);
>>>
>>> Disabling interrupt while invalidating iotlb is certainly unacceptable.
>>>
>>> Actually there is no need to walk devices. Under dmar_domain there
>>> is already a list of attached iommu's.
>>
>> Walking device is only necessary when invalidating device TLB. For iotlb
>> invalidation, it only needs to know the iommu's.
>>
>
> even for device tlb we may think whether there is any better way
> to avoid disabling interrupt. It's a slow path, especially in a guest.
I ever tried this. But some device drivers call iommu_unmap() in the
interrupt critical path. :-( So we have a long way to go.
Best regards,
baolu
Powered by blists - more mailing lists