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Tue, 09 Jun 2020 07:26:50 -0400 X-MC-Unique: S2PpnDTgPTiisaPWCBSlBg-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 63FB1835B42; Tue, 9 Jun 2020 11:26:49 +0000 (UTC) Received: from [10.36.110.37] (unknown [10.36.110.37]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 33746891E8; Tue, 9 Jun 2020 11:26:40 +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: <0293f676-865a-4175-0fcd-7a8ff7c0a9e8@redhat.com> Date: Tue, 9 Jun 2020 13:26:38 +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? > > 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 > >>>>> 2. no need callfd to be last. >>>>> >>>>> Queues that will be configured later will be configured to the HW >>>>> when the >>>> virtq becoming enabled. >>>>> >>>>> >>>>> What do think? >>>> >>>> Maybe I did not understood what you mean, so please correct me if >> needed. >>>> >>>> If I understood correctly, then your suggestion is just to remove the >>>> workaround, but it has been introduced by Intel because the callfd >>>> gets set a second time in some cases. >>> >>> Not to remove the WA, just to improve it๐Ÿ˜Š >>> >>> I don't sure I understand the issue here, can you add details? >> >> My understanding is that callfd is sent early by Qemu but is then updated >> after by Qemu and we have no way to distinguish whether the first one is >> valid or not... I did a bit of archeology and found this explanation from Xiao: >> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Finbox >> .dpdk.org%2Fstable%2FB7F2E978279D1D49A3034B7786DACF407AFAA0C6%4 >> 0SHSMSX106.ccr.corp.intel.com%2F&data=02%7C01%7Cmatan%40mella >> nox.com%7Cdafcc4fcf4074202227208d80c542b1e%7Ca652971c7d2e4d9ba6a4 >> d149256f461b%7C0%7C0%7C637272902927735523&sdata=hvUJq5VdXH >> usbBp1y%2BSr1Yp2AukNQZbRnFS6dR3rgMw%3D&reserved=0 >> >> I haven't managed to reproduce the issue myself, so that's why I'm a bit >> reluctant in trying to improve it. Ideally Xiao could try to reproduce the issue, >> so that if we can find something more elegant (and that does make Virtio- >> user to work without the SET_STATUS support) we can be confident in >> merging it (and maybe even backport it). > > > It looks like very specific case WA which breaks other cases, for example: > Guest poll mode driver: callfd is configured twice one by one, the first is X=!-1 and the second -1, here vdpa configuration may be triggered in the first one what make the driver think wrongly that the queue is not in poll mode. Yes, I agree that it would be better to avoid having this workaround, as it may create regressions. > I will send RFC patch with my suggestion. Thanks. Xiao, any chance you try to reproduce the initial issue? This way we can test Matan's RFC. Maxime > >> Regards, >> Maxime >> >>> >>>> >>>> Thanks, >>>> Maxime >>>>> >>>>>> if (vdpa_dev->ops->dev_conf(dev->vid)) >>>>>> VHOST_LOG_CONFIG(ERR, >>>>>> "Failed to configure vDPA device\n"); >>>>>> -- >>>>>> 2.25.4 >>>>> >>> >