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From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Bruce Richardson <bruce.richardson@intel.com>,
	Jason Wang <jasowang@redhat.com>
Cc: Thanneeru Srinivasulu <dev.srinivasulu@gmail.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] Query : Does Binding with vfio-pci is supported inside qemu-kvm guest/vm instance.?
Date: Tue, 12 Mar 2019 10:57:16 +0000	[thread overview]
Message-ID: <38327cd0-7fa2-9172-5343-0cded8e51594@intel.com> (raw)
In-Reply-To: <20190312102009.GA932176@bricha3-MOBL.ger.corp.intel.com>

On 12-Mar-19 10:20 AM, Bruce Richardson wrote:
> On Tue, Mar 12, 2019 at 05:54:39PM +0800, Jason Wang wrote:
>>
>> On 2019/3/12 下午5:42, Thanneeru Srinivasulu wrote:
>>> Thanks Bruce..
>>>
>>> On Tue, Mar 12, 2019 at 3:08 PM Bruce Richardson
>>> <bruce.richardson@intel.com> wrote:
>>>> On Tue, Mar 12, 2019 at 10:57:55AM +0530, Thanneeru Srinivasulu wrote:
>>>>> Hi Everyone.
>>>>>
>>>>> I did attached pice  to Guest VM using vfio-pci with qemu command, and then
>>>>> tried binding the pcie bdf with vfio-pci, observing binding failure with
>>>>> vfio-pci.
>>>>>
>>>>> Where as when tryied with igb_uio, everything works fine.
>>>>>
>>>>> Does Binding with vfio-pci is supported inside VM/guest?
>>>>>
>>>> vfio support requires the presence of an IOMMU, and you generally don't
>>>> have an IOMMU available in a VM.
>>>>
>>>> /Bruce
>>
>>
>> Actually, Qemu support vIOMMU + VFIO in guest[1], all you need is to add a
>> intel IOMMU and enabling caching mode.
>>
>> Thanks
>>
>>
>> [1]
>>
>> https://www.lfasiallc.com/wp-content/uploads/2017/11/Device-Assignment-with-Nested-Guests-and-DPDK_Peter-Xu.pdf
>>
> Thanks for the info.
> 
> /Bruce
> 

One more thing: even without vIOMMU, VFIO has no-IOMMU mode which can be 
enabled (for a recent-enough kernel). This will make VFIO work even in 
cases where the guest doesn't have IOMMU emulation. See? There's no 
reason to use igb_uio, ever! :D

-- 
Thanks,
Anatoly

  reply	other threads:[~2019-03-12 10:57 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-12  5:27 Thanneeru Srinivasulu
2019-03-12  9:38 ` Bruce Richardson
2019-03-12  9:42   ` Thanneeru Srinivasulu
2019-03-12  9:54     ` Jason Wang
2019-03-12 10:20       ` Bruce Richardson
2019-03-12 10:57         ` Burakov, Anatoly [this message]
     [not found]           ` <CGME20190312110957eucas1p1af74c8d26bf80fd815847ed8086a1e78@eucas1p1.samsung.com>
2019-03-12 11:09             ` Ilya Maximets
2019-04-02 10:38           ` John Sucaet
2019-04-02 10:38             ` John Sucaet
2019-04-02 13:38             ` Burakov, Anatoly
2019-04-02 13:38               ` Burakov, Anatoly
2019-04-03  7:49               ` John Sucaet
2019-04-03  7:49                 ` John Sucaet
2019-04-03  7:54                 ` Maxime Coquelin
2019-04-03  7:54                   ` Maxime Coquelin
2019-04-04  8:23                   ` John Sucaet
2019-04-04  8:23                     ` John Sucaet

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