From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 7B6311B4E3; Wed, 10 Oct 2018 12:23:49 +0200 (CEST) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 90DC83082A43; Wed, 10 Oct 2018 10:23:48 +0000 (UTC) Received: from [10.36.112.48] (ovpn-112-48.ams2.redhat.com [10.36.112.48]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C0C6068DA7; Wed, 10 Oct 2018 10:23:41 +0000 (UTC) To: Tiwei Bie Cc: dev@dpdk.org, zhihong.wang@intel.com, jfreimann@redhat.com, nicknickolaev@gmail.com, i.maximets@samsung.com, bruce.richardson@intel.com, alejandro.lucero@netronome.com, dgilbert@redhat.com, stable@dpdk.org References: <20181009205426.21219-1-maxime.coquelin@redhat.com> <20181009205426.21219-18-maxime.coquelin@redhat.com> <20181010101725.GD2956@debian> From: Maxime Coquelin Message-ID: <88027651-738e-4140-4d59-4987443c52be@redhat.com> Date: Wed, 10 Oct 2018 12:23:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181010101725.GD2956@debian> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Wed, 10 Oct 2018 10:23:48 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH v5 17/19] vhost: restrict postcopy live-migration enablement 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: , X-List-Received-Date: Wed, 10 Oct 2018 10:23:49 -0000 On 10/10/2018 12:17 PM, Tiwei Bie wrote: > On Tue, Oct 09, 2018 at 10:54:24PM +0200, Maxime Coquelin wrote: >> Postcopy live-migration feature requires the application to >> not populate the guest memory. As the vhost library cannot >> prevent the application to that (e.g. preventing the >> application to call mlockall()), the feature is disabled by >> default. >> >> The application should only enable the feature if it does not >> force the guest memory to be populated. >> >> In case the user passes the RTE_VHOST_USER_POSTCOPY_SUPPORT >> flag at registration but the feature was not compiled, >> registration fails. >> >> For the same reason, postcopy and dequeue zero copy features >> are not compatible, so don't advertize postcopy support if >> dequeue zero copy is requested. >> >> Signed-off-by: Maxime Coquelin >> --- >> doc/guides/prog_guide/vhost_lib.rst | 8 ++++++++ >> lib/librte_vhost/rte_vhost.h | 1 + >> lib/librte_vhost/socket.c | 30 ++++++++++++++++++++++++++--- >> 3 files changed, 36 insertions(+), 3 deletions(-) >> >> diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst >> index 77af4d775..c77df338f 100644 >> --- a/doc/guides/prog_guide/vhost_lib.rst >> +++ b/doc/guides/prog_guide/vhost_lib.rst >> @@ -106,6 +106,14 @@ The following is an overview of some key Vhost API functions: >> Enabling this flag with these Qemu version results in Qemu being blocked >> when multiple queue pairs are declared. >> >> + - ``RTE_VHOST_USER_POSTCOPY_SUPPORT`` >> + >> + Postcopy live-migration support will be enabled when this flag is set. >> + It is disabled by default. >> + >> + Enabling this flag should only be done when the calling application does >> + not pre-fault the guest shared memory, otherwise migration would fail. >> + >> * ``rte_vhost_driver_set_features(path, features)`` >> >> This function sets the feature bits the vhost-user driver supports. The >> diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h >> index 9292c89c5..d280ac420 100644 >> --- a/lib/librte_vhost/rte_vhost.h >> +++ b/lib/librte_vhost/rte_vhost.h >> @@ -28,6 +28,7 @@ extern "C" { >> #define RTE_VHOST_USER_NO_RECONNECT (1ULL << 1) >> #define RTE_VHOST_USER_DEQUEUE_ZERO_COPY (1ULL << 2) >> #define RTE_VHOST_USER_IOMMU_SUPPORT (1ULL << 3) >> +#define RTE_VHOST_USER_POSTCOPY_SUPPORT (1ULL << 4) >> >> /** Protocol features. */ >> #ifndef VHOST_USER_PROTOCOL_F_MQ >> diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c >> index 7cad5593e..4b221a805 100644 >> --- a/lib/librte_vhost/socket.c >> +++ b/lib/librte_vhost/socket.c >> @@ -51,6 +51,8 @@ struct vhost_user_socket { >> uint64_t supported_features; >> uint64_t features; >> >> + uint64_t protocol_features; > > In vhost_user_set_protocol_features() in vhost_user.c, > we also need to find a way to check with this field > instead of VHOST_USER_PROTOCOL_FEATURES when receiving > the protocol features from QEMU. Makes sense. Something like calling rte_vhost_driver_get_protocol_features() there and use result instead of VHOST_USER_PROTOCOL_FEATURES should do the trick. >> + >> /* >> * Device id to identify a specific backend device. >> * It's set to -1 for the default software implementation. > [...] >