On Thu, Aug 24, 2017 at 08:27:09PM +0100, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > Open a userfaultfd (on a postcopy_advise) and send it back in > the reply to the qemu for it to monitor. > > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > --- > contrib/libvhost-user/libvhost-user.c | 26 +++++++++++++++++++++++--- > contrib/libvhost-user/libvhost-user.h | 3 +++ > 2 files changed, 26 insertions(+), 3 deletions(-) > > diff --git a/contrib/libvhost-user/libvhost-user.c > b/contrib/libvhost-user/libvhost-user.c > index 47884c0a15..f9b5b12b28 100644 > --- a/contrib/libvhost-user/libvhost-user.c > +++ b/contrib/libvhost-user/libvhost-user.c > @@ -15,6 +15,7 @@ > > #include <qemu/osdep.h> > #include <sys/eventfd.h> > +#include <sys/syscall.h> > #include <linux/vhost.h> > > #include "qemu/atomic.h" > @@ -773,11 +774,30 @@ vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg) > static bool > vu_set_postcopy_advise(VuDev *dev, VhostUserMsg *vmsg) > { > - /* TODO: Open ufd, pass it back in the request > - * TODO: Add addresses > - */ > + struct uffdio_api api_struct; > + > + dev->postcopy_ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); > + /* TODO: Add addresses */ > vmsg->payload.u64 = 0xcafe; > vmsg->size = sizeof(vmsg->payload.u64); > + > + if (dev->postcopy_ufd == -1) { > + vu_panic(dev, "Userfaultfd not available: %s", strerror(errno)); > + goto out;
We got error but still goto out? I feel like we should reply with some kind of error code when any error happens. > + } > + api_struct.api = UFFD_API; > + api_struct.features = 0; > + if (ioctl(dev->postcopy_ufd, UFFDIO_API, &api_struct)) { > + vu_panic(dev, "Failed UFFDIO_API: %s", strerror(errno)); > + close(dev->postcopy_ufd); > + dev->postcopy_ufd = -1; > + goto out; Same here. > + } > + /* TODO: Stash feature flags somewhere */ > +out: > + /* Return a ufd to the QEMU */ > + vmsg->fd_num = 1; > + vmsg->fds[0] = dev->postcopy_ufd; > return true; /* = send a reply */ > } > > diff --git a/contrib/libvhost-user/libvhost-user.h > b/contrib/libvhost-user/libvhost-user.h > index 3987ce643d..3e8efdd919 100644 > --- a/contrib/libvhost-user/libvhost-user.h > +++ b/contrib/libvhost-user/libvhost-user.h > @@ -234,6 +234,9 @@ struct VuDev { > * re-initialize */ > vu_panic_cb panic; > const VuDevIface *iface; > + > + /* Postcopy data */ > + int postcopy_ufd; > }; > > typedef struct VuVirtqElement { > -- > 2.13.5 > -- Peter Xu