On Thu, Aug 24, 2017 at 08:27:09PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <[email protected]>
>
> 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 <[email protected]>
> ---
> 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
