| Message ID | 20180308195811.24894-6-dgilbert@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | postcopy+vhost-user/shared ram | expand |
On Thu, Mar 8, 2018 at 8:57 PM, Dr. David Alan Gilbert (git) <dgilbert@redhat.com> wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > 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 <dgilbert@redhat.com> > Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > contrib/libvhost-user/libvhost-user.h | 2 ++ > docs/interop/vhost-user.txt | 10 +++++++++ > hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++- > 3 files changed, 52 insertions(+), 1 deletion(-) > > 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); > -- > 2.14.3 > >
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);