diff options
| -rw-r--r-- | contrib/libvhost-user/libvhost-user.h | 2 | ||||
| -rw-r--r-- | docs/interop/vhost-user.txt | 10 | ||||
| -rw-r--r-- | hw/virtio/vhost-user.c | 41 |
3 files changed, 52 insertions, 1 deletions
diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h index 18f95f65d7..96db29c4ce 100644 --- a/contrib/libvhost-user/libvhost-user.h +++ b/contrib/libvhost-user/libvhost-user.h @@ -48,6 +48,8 @@ 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_CRYPTO_SESSION = 7, + VHOST_USER_PROTOCOL_F_PAGEFAULT = 8, VHOST_USER_PROTOCOL_F_MAX }; diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt index cb3a7595aa..91a572d781 100644 --- a/docs/interop/vhost-user.txt +++ b/docs/interop/vhost-user.txt @@ -290,6 +290,15 @@ 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. + Memory access ------------- @@ -369,6 +378,7 @@ Protocol features #define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5 #define VHOST_USER_PROTOCOL_F_CROSS_ENDIAN 6 #define VHOST_USER_PROTOCOL_F_CRYPTO_SESSION 7 +#define VHOST_USER_PROTOCOL_F_PAGEFAULT 8 Master message types -------------------- diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 41ff5cff41..aab35c4845 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -18,6 +18,8 @@ #include "qemu/error-report.h" #include "qemu/sockets.h" #include "sysemu/cryptodev.h" +#include "migration/migration.h" +#include "migration/postcopy-ram.h" #include <sys/ioctl.h> #include <sys/socket.h> @@ -41,7 +43,7 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_SLAVE_REQ = 5, VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6, VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7, - + VHOST_USER_PROTOCOL_F_PAGEFAULT = 8, VHOST_USER_PROTOCOL_F_MAX }; @@ -164,8 +166,10 @@ 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) @@ -791,6 +795,33 @@ 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; @@ -802,6 +833,7 @@ 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); @@ -858,6 +890,9 @@ 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; } @@ -868,6 +903,10 @@ 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); + u->postcopy_notifier.notify = NULL; + } if (u->slave_fd >= 0) { qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); close(u->slave_fd); |