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Tue, 09 Jun 2020 13:23:09 -0400 X-MC-Unique: U5mO-Zv0OiqSMxlVLQ8cOg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 006E38015CE; Tue, 9 Jun 2020 17:23:08 +0000 (UTC) Received: from [10.36.110.37] (unknown [10.36.110.37]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2B6D489262; Tue, 9 Jun 2020 17:23:04 +0000 (UTC) To: Matan Azrad , "xiaolong.ye@intel.com" , Shahaf Shuler , "amorenoz@redhat.com" , "xiao.w.wang@intel.com" , Slava Ovsiienko , "dev@dpdk.org" Cc: "jasowang@redhat.com" , "lulu@redhat.com" References: <20200514080218.1435344-1-maxime.coquelin@redhat.com> <20200514080218.1435344-10-maxime.coquelin@redhat.com> <0216165f-aedd-06c7-5a90-2cd0d238b143@redhat.com> <97528794-aa14-37da-a5bb-1e1d46e9127a@redhat.com> From: Maxime Coquelin Autocrypt: addr=maxime.coquelin@redhat.com; keydata= mQINBFOEQQIBEADjNLYZZqghYuWv1nlLisptPJp+TSxE/KuP7x47e1Gr5/oMDJ1OKNG8rlNg kLgBQUki3voWhUbMb69ybqdMUHOl21DGCj0BTU3lXwapYXOAnsh8q6RRM+deUpasyT+Jvf3a gU35dgZcomRh5HPmKMU4KfeA38cVUebsFec1HuJAWzOb/UdtQkYyZR4rbzw8SbsOemtMtwOx YdXodneQD7KuRU9IhJKiEfipwqk2pufm2VSGl570l5ANyWMA/XADNhcEXhpkZ1Iwj3TWO7XR uH4xfvPl8nBsLo/EbEI7fbuUULcAnHfowQslPUm6/yaGv6cT5160SPXT1t8U9QDO6aTSo59N jH519JS8oeKZB1n1eLDslCfBpIpWkW8ZElGkOGWAN0vmpLfdyiqBNNyS3eGAfMkJ6b1A24un /TKc6j2QxM0QK4yZGfAxDxtvDv9LFXec8ENJYsbiR6WHRHq7wXl/n8guyh5AuBNQ3LIK44x0 KjGXP1FJkUhUuruGyZsMrDLBRHYi+hhDAgRjqHgoXi5XGETA1PAiNBNnQwMf5aubt+mE2Q5r qLNTgwSo2dpTU3+mJ3y3KlsIfoaxYI7XNsPRXGnZi4hbxmeb2NSXgdCXhX3nELUNYm4ArKBP LugOIT/zRwk0H0+RVwL2zHdMO1Tht1UOFGfOZpvuBF60jhMzbQARAQABtCxNYXhpbWUgQ29x dWVsaW4gPG1heGltZS5jb3F1ZWxpbkByZWRoYXQuY29tPokCOAQTAQIAIgUCV3u/5QIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQyjiNKEaHD4ma2g/+P+Hg9WkONPaY1J4AR7Uf kBneosS4NO3CRy0x4WYmUSLYMLx1I3VH6SVjqZ6uBoYy6Fs6TbF6SHNc7QbB6Qjo3neqnQR1 71Ua1MFvIob8vUEl3jAR/+oaE1UJKrxjWztpppQTukIk4oJOmXbL0nj3d8dA2QgHdTyttZ1H xzZJWWz6vqxCrUqHU7RSH9iWg9R2iuTzii4/vk1oi4Qz7y/q8ONOq6ffOy/t5xSZOMtZCspu Mll2Szzpc/trFO0pLH4LZZfz/nXh2uuUbk8qRIJBIjZH3ZQfACffgfNefLe2PxMqJZ8mFJXc RQO0ONZvwoOoHL6CcnFZp2i0P5ddduzwPdGsPq1bnIXnZqJSl3dUfh3xG5ArkliZ/++zGF1O wvpGvpIuOgLqjyCNNRoR7cP7y8F24gWE/HqJBXs1qzdj/5Hr68NVPV1Tu/l2D1KMOcL5sOrz 2jLXauqDWn1Okk9hkXAP7+0Cmi6QwAPuBT3i6t2e8UdtMtCE4sLesWS/XohnSFFscZR6Vaf3 gKdWiJ/fW64L6b9gjkWtHd4jAJBAIAx1JM6xcA1xMbAFsD8gA2oDBWogHGYcScY/4riDNKXi lw92d6IEHnSf6y7KJCKq8F+Jrj2BwRJiFKTJ6ChbOpyyR6nGTckzsLgday2KxBIyuh4w+hMq TGDSp2rmWGJjASq5Ag0EVPSbkwEQAMkaNc084Qvql+XW+wcUIY+Dn9A2D1gMr2BVwdSfVDN7 0ZYxo9PvSkzh6eQmnZNQtl8WSHl3VG3IEDQzsMQ2ftZn2sxjcCadexrQQv3Lu60Tgj7YVYRM H+fLYt9W5YuWduJ+FPLbjIKynBf6JCRMWr75QAOhhhaI0tsie3eDsKQBA0w7WCuPiZiheJaL 4MDe9hcH4rM3ybnRW7K2dLszWNhHVoYSFlZGYh+MGpuODeQKDS035+4H2rEWgg+iaOwqD7bg CQXwTZ1kSrm8NxIRVD3MBtzp9SZdUHLfmBl/tLVwDSZvHZhhvJHC6Lj6VL4jPXF5K2+Nn/Su CQmEBisOmwnXZhhu8ulAZ7S2tcl94DCo60ReheDoPBU8PR2TLg8rS5f9w6mLYarvQWL7cDtT d2eX3Z6TggfNINr/RTFrrAd7NHl5h3OnlXj7PQ1f0kfufduOeCQddJN4gsQfxo/qvWVB7PaE 1WTIggPmWS+Xxijk7xG6x9McTdmGhYaPZBpAxewK8ypl5+yubVsE9yOOhKMVo9DoVCjh5To5 aph7CQWfQsV7cd9PfSJjI2lXI0dhEXhQ7lRCFpf3V3mD6CyrhpcJpV6XVGjxJvGUale7+IOp sQIbPKUHpB2F+ZUPWds9yyVxGwDxD8WLqKKy0WLIjkkSsOb9UBNzgRyzrEC9lgQ/ABEBAAGJ Ah8EGAECAAkFAlT0m5MCGwwACgkQyjiNKEaHD4nU8hAAtt0xFJAy0sOWqSmyxTc7FUcX+pbD KVyPlpl6urKKMk1XtVMUPuae/+UwvIt0urk1mXi6DnrAN50TmQqvdjcPTQ6uoZ8zjgGeASZg jj0/bJGhgUr9U7oG7Hh2F8vzpOqZrdd65MRkxmc7bWj1k81tOU2woR/Gy8xLzi0k0KUa8ueB iYOcZcIGTcs9CssVwQjYaXRoeT65LJnTxYZif2pfNxfINFzCGw42s3EtZFteczClKcVSJ1+L +QUY/J24x0/ocQX/M1PwtZbB4c/2Pg/t5FS+s6UB1Ce08xsJDcwyOPIH6O3tccZuriHgvqKP yKz/Ble76+NFlTK1mpUlfM7PVhD5XzrDUEHWRTeTJSvJ8TIPL4uyfzhjHhlkCU0mw7Pscyxn DE8G0UYMEaNgaZap8dcGMYH/96EfE5s/nTX0M6MXV0yots7U2BDb4soLCxLOJz4tAFDtNFtA wLBhXRSvWhdBJZiig/9CG3dXmKfi2H+wdUCSvEFHRpgo7GK8/Kh3vGhgKmnnxhl8ACBaGy9n fxjSxjSO6rj4/MeenmlJw1yebzkX8ZmaSi8BHe+n6jTGEFNrbiOdWpJgc5yHIZZnwXaW54QT UhhSjDL1rV2B4F28w30jYmlRmm2RdN7iCZfbyP3dvFQTzQ4ySquuPkIGcOOHrvZzxbRjzMx1 Mwqu3GQ= Message-ID: <64c59e91-79ef-bc55-bc64-1995cfb03c84@redhat.com> Date: Tue, 9 Jun 2020 19:23:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH 9/9] vhost: only use vDPA config workaround if needed X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 6/9/20 1:09 PM, Matan Azrad wrote: > Hi Maxime > > From: Maxime Coquelin >> Hi Matan, >> >> On 6/8/20 11:19 AM, Matan Azrad wrote: >>> Hi Maxime >>> >>> From: Maxime Coquelin: >>>> Hi Matan, >>>> >>>> On 6/7/20 12:38 PM, Matan Azrad wrote: >>>>> Hi Maxime >>>>> >>>>> Thanks for the huge work. >>>>> Please see a suggestion inline. >>>>> >>>>> From: Maxime Coquelin: >>>>>> Sent: Thursday, May 14, 2020 11:02 AM >>>>>> To: xiaolong.ye@intel.com; Shahaf Shuler ; >>>>>> Matan Azrad ; amorenoz@redhat.com; >>>>>> xiao.w.wang@intel.com; Slava Ovsiienko >> ; >>>>>> dev@dpdk.org >>>>>> Cc: jasowang@redhat.com; lulu@redhat.com; Maxime Coquelin >>>>>> >>>>>> Subject: [PATCH 9/9] vhost: only use vDPA config workaround if >>>>>> needed >>>>>> >>>>>> Now that we have Virtio device status support, let's only use the >>>>>> vDPA workaround if it is not supported. >>>>>> >>>>>> This patch also document why Virtio device status protocol feature >>>>>> support is strongly advised. >>>>>> >>>>>> Signed-off-by: Maxime Coquelin >>>>>> --- >>>>>> lib/librte_vhost/vhost_user.c | 16 ++++++++++++++-- >>>>>> 1 file changed, 14 insertions(+), 2 deletions(-) >>>>>> >>>>>> diff --git a/lib/librte_vhost/vhost_user.c >>>>>> b/lib/librte_vhost/vhost_user.c index e5a44be58d..67e96a872a 100644 >>>>>> --- a/lib/librte_vhost/vhost_user.c >>>>>> +++ b/lib/librte_vhost/vhost_user.c >>>>>> @@ -2847,8 +2847,20 @@ vhost_user_msg_handler(int vid, int fd) >>>>>> if (!vdpa_dev) >>>>>> goto out; >>>>>> >>>>>> - if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED) && >>>>>> - request == VHOST_USER_SET_VRING_CALL) { >>>>>> + if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) { >>>>>> + /* >>>>>> + * Workaround when Virtio device status protocol >>>>>> + * feature is not supported, wait for SET_VRING_CALL >>>>>> + * request. This is not ideal as some frontends like >>>>>> + * Virtio-user may not send this request, so vDPA device >>>>>> + * may never be configured. Virtio device status support >>>>>> + * on frontend side is strongly advised. >>>>>> + */ >>>>>> + if (!(dev->protocol_features & >>>>>> + (1ULL << >>>>>> VHOST_USER_PROTOCOL_F_STATUS)) && >>>>>> + (request != >>>>>> VHOST_USER_SET_VRING_CALL)) >>>>>> + goto out; >>>>>> + >>>>> >>>>> When status protocol feature is not supported, in the current code, >>>>> the >>>> vDPA configuration triggering depends in: >>>>> 1. Device is ready - all the queues are configured (datapath >>>>> addresses, >>>> callfd and kickfd) . >>>>> 2. last command is callfd. >>>>> >>>>> >>>>> The code doesn't take into account that some queues may stay disabled. >>>>> Maybe the correct timing is: >>>>> 1. Device is ready - all the enabled queues are configured and MEM >>>>> table is >>>> configured. >>>> >>>> I think current virtio_is_ready() already assumes the mem table is >>>> configured, otherwise we would not have vq->desc, vq->used and >>>> vq->avail being set as it needs to be translated using the mem table. >>>> >>> Yes, but if you don't expect to check them for disabled queues you need to >> check mem table to be sure it was set. >> >> Even disabled queues should be allocated/configured by the guest driver. > Is it by spec? Sorry, that was a misunderstanding from my side. The number of queues set by the driver using MQ_VQ_PAIRS_SET control message have to be allocated and configured by the driver: http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-1940001 > We saw that windows virtio guest driver doesn't configure disabled queues. > Is it bug in windows guest? > You probably can take a look here: > https://github.com/virtio-win/kvm-guest-drivers-windows > Indeed it limits the number of queue pairs to the number of CPUs. This is done here: https://github.com/virtio-win/kvm-guest-drivers-windows/blob/edda3f50a17015aab1450ca09e3263c7409e4001/NetKVM/Common/ParaNdis_Common.cpp#L956 Linux does the same by the way: https://elixir.bootlin.com/linux/latest/source/drivers/net/virtio_net.c#L3092 We rarely face this issue because by default, the management layers usually set the number of queue pairs to the number of vCPUs if multiqueue is enabled. But the problem is real. In my opinion, the problem is more on Vhost-user spec side and/or Vhost- user backend. The DPDK backend allocates queue pairs for every time it receives a Vhost-user message setting a new queue (callfd, kickfd, enable,... see vhost_user_check_and_alloc_queue_pair()). And then virtio_is_ready() waits for all the allocated queue pairs to be initialized. The problem is that QEMU sends some if these messages even for queues that aren't (or won't be) initialized, as you can see in below log where I reproduced the issue with Windows 10: https://pastebin.com/YYCfW9Y3 I don't see how the backend could know the guest driver is done with currently received information from Qemu as it seems to him some queues are partially initialized (callfd is set). With VHOST_USER_SET_STATUS, we will be able to handle this properly, as the backend can be sure the guest won't initialize more queues as soon as DRIVER_OK Virtio status bit is set. In my v2, I can add one patch to handle this case properly, by "destorying" queues metadata as soon as DRIVER_OK is received. Note that it was the exact reason why I first tried to add support for VHOST_USER_SET_STATUS more than two years ago...: https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg04560.html What do you think? Regards, Maxime