From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52145) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dkxna-00025K-2O for qemu-devel@nongnu.org; Thu, 24 Aug 2017 15:28:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dkxnY-0004SW-Qf for qemu-devel@nongnu.org; Thu, 24 Aug 2017 15:28:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48928) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dkxnY-0004Ri-Ga for qemu-devel@nongnu.org; Thu, 24 Aug 2017 15:28:12 -0400 From: "Dr. David Alan Gilbert (git)" Date: Thu, 24 Aug 2017 20:27:06 +0100 Message-Id: <20170824192730.8440-9-dgilbert@redhat.com> In-Reply-To: <20170824192730.8440-1-dgilbert@redhat.com> References: <20170824192730.8440-1-dgilbert@redhat.com> Subject: [Qemu-devel] [RFC v2 08/32] postcopy: Add vhost-user flag for postcopy and check it List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, maxime.coquelin@redhat.com, a.perevalov@samsung.com, mst@redhat.com, marcandre.lureau@redhat.com Cc: quintela@redhat.com, peterx@redhat.com, lvivier@redhat.com, aarcange@redhat.com, felipe@nutanix.com From: "Dr. David Alan Gilbert" Add a vhost feature flag for postcopy support, and use the postcopy notifier to check it before allowing postcopy. Signed-off-by: Dr. David Alan Gilbert --- contrib/libvhost-user/libvhost-user.h | 1 + docs/interop/vhost-user.txt | 10 +++++++++ hw/virtio/vhost-user.c | 40 ++++++++++++++++++++++++++++++++++- 3 files changed, 50 insertions(+), 1 deletion(-) diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h index acd019876d..95d0d34a28 100644 --- a/contrib/libvhost-user/libvhost-user.h +++ b/contrib/libvhost-user/libvhost-user.h @@ -34,6 +34,7 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_MQ = 0, VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1, VHOST_USER_PROTOCOL_F_RARP = 2, + VHOST_USER_PROTOCOL_F_PAGEFAULT = 7, VHOST_USER_PROTOCOL_F_MAX }; diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt index 954771d0d8..a279560eb0 100644 --- a/docs/interop/vhost-user.txt +++ b/docs/interop/vhost-user.txt @@ -273,6 +273,15 @@ Once the source has finished migration, rings will be stopped by the source. No further update must be done before rings are restarted. +In postcopy migration the slave is started before all the memory has been +received from the source host, and care must be taken to avoid accessing pages +that have yet to be received. The slave opens a 'userfault'-fd and registers +the memory with it; this fd is then passed back over to the master. +The master services requests on the userfaultfd for pages that are accessed +and when the page is available it performs WAKE ioctl's on the userfaultfd +to wake the stalled slave. The client indicates support for this via the +VHOST_USER_PROTOCOL_F_PAGEFAULT feature. + IOMMU support ------------- @@ -327,6 +336,7 @@ Protocol features #define VHOST_USER_PROTOCOL_F_MTU 4 #define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5 #define VHOST_USER_PROTOCOL_F_CROSS_ENDIAN 6 +#define VHOST_USER_PROTOCOL_F_PAGEFAULT 7 Master message types -------------------- diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 093675ed98..c51bbd1296 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -17,6 +17,8 @@ #include "sysemu/kvm.h" #include "qemu/error-report.h" #include "qemu/sockets.h" +#include "migration/migration.h" +#include "migration/postcopy-ram.h" #include #include @@ -34,7 +36,7 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_NET_MTU = 4, VHOST_USER_PROTOCOL_F_SLAVE_REQ = 5, VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6, - + VHOST_USER_PROTOCOL_F_PAGEFAULT = 7, VHOST_USER_PROTOCOL_F_MAX }; @@ -123,8 +125,10 @@ static VhostUserMsg m __attribute__ ((unused)); #define VHOST_USER_VERSION (0x1) struct vhost_user { + struct vhost_dev *dev; CharBackend *chr; int slave_fd; + NotifierWithReturn postcopy_notifier; }; static bool ioeventfd_enabled(void) @@ -720,6 +724,33 @@ out: return ret; } +static int vhost_user_postcopy_notifier(NotifierWithReturn *notifier, + void *opaque) +{ + struct PostcopyNotifyData *pnd = opaque; + struct vhost_user *u = container_of(notifier, struct vhost_user, + postcopy_notifier); + struct vhost_dev *dev = u->dev; + + switch (pnd->reason) { + case POSTCOPY_NOTIFY_PROBE: + if (!virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_PAGEFAULT)) { + /* TODO: Get the device name into this error somehow */ + error_setg(pnd->errp, + "vhost-user backend not capable of postcopy"); + return -ENOENT; + } + break; + + default: + /* We ignore notifications we don't know */ + break; + } + + return 0; +} + static int vhost_user_init(struct vhost_dev *dev, void *opaque) { uint64_t features, protocol_features; @@ -731,6 +762,7 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque) u = g_new0(struct vhost_user, 1); u->chr = opaque; u->slave_fd = -1; + u->dev = dev; dev->opaque = u; err = vhost_user_get_features(dev, &features); @@ -787,6 +819,9 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque) return err; } + u->postcopy_notifier.notify = vhost_user_postcopy_notifier; + postcopy_add_notifier(&u->postcopy_notifier); + return 0; } @@ -797,6 +832,9 @@ static int vhost_user_cleanup(struct vhost_dev *dev) assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER); u = dev->opaque; + if (u->postcopy_notifier.notify) { + postcopy_remove_notifier(&u->postcopy_notifier); + } if (u->slave_fd >= 0) { qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); close(u->slave_fd); -- 2.13.5