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Subject: Re: [virtio-dev] Re: [PATCH v1 2/2] virtio-mmio: add features for
 virtio-mmio specification version 3
To:     "Liu, Jiang" <gerry@linux.alibaba.com>
Cc:     "Liu, Jing2" <jing2.liu@linux.intel.com>,
        Zha Bin <zhabin@linux.alibaba.com>,
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From:   Jason Wang <jasowang@redhat.com>
Message-ID: <7e151886-408e-2c1d-3958-77c26b8a4ac0@redhat.com>
Date:   Fri, 3 Jan 2020 17:12:38 +0800
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On 2020/1/3 =E4=B8=8B=E5=8D=882:14, Liu, Jiang wrote:
>> Ok, I get you now.
>>
>> But still, having fixed number of MSIs is less flexible. E.g:
>>
>> - for x86, processor can only deal with about 250 interrupt vectors.
>> - driver may choose to share MSI vectors [1] (which is not merged but =
we will for sure need it)
> Thanks for the info:)
> X86 systems roughly have NCPU * 200 vectors available for device interr=
upts.
> The proposed patch tries to map multiple event sources to an interrupt =
vector, to avoid running out of x86 CPU vectors.
> Many virtio mmio devices may have several or tens of event sources, and=
 it=E2=80=99s rare to have hundreds of event sources.
> So could we treat the dynamic mapping between event sources and interru=
pt vectors as an advanced optional feature?
>

Maybe, but I still prefer to implement it if it is not too complex.=20
Let's see Michael's opinion on this.

Thanks