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Subject: Re: [RFC] /dev/ioasid uAPI proposal
From:   Jason Wang <jasowang@redhat.com>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     "Tian, Kevin" <kevin.tian@intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Liu Yi L <yi.l.liu@linux.intel.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "Alex Williamson (alex.williamson@redhat.com)\"\"" 
        <alex.williamson@redhat.com>, David Woodhouse <dwmw2@infradead.org>
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Date:   Thu, 10 Jun 2021 12:03:52 +0800
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?? 2021/6/10 ????10:00, Jason Wang д??:
>
> ?? 2021/6/8 ????9:20, Jason Gunthorpe д??:
>> On Tue, Jun 08, 2021 at 09:10:42AM +0800, Jason Wang wrote:
>>
>>> Well, this sounds like a re-invention of io_uring which has already 
>>> worked
>>> for multifds.
>> How so? io_uring is about sending work to the kernel, not getting
>> structued events back?
>
>
> Actually it can. Userspace can poll multiple fds via preparing 
> multiple sqes with IORING_OP_ADD flag.


IORING_OP_POLL_ADD actually.

Thanks


>
>
>>
>> It is more like one of the perf rings
>
>
> This means another ring and we need introduce ioctl() to add or remove 
> ioasids from the poll. And it still need a kind of fallback like a 
> list if the ring is full.
>
> Thanks
>
>
>>
>> Jason
>>