Commit 4275cd99 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Michael S. Tsirkin
Browse files

libvhost-user: Claim support for postcopy 



Tell QEMU we understand the protocol features needed for postcopy.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 29d8fa7f

contrib/libvhost-user/libvhost-user.c

+33 −0
Original line number Diff line number Diff line
@@ -185,6 +185,35 @@ vmsg_close_fds(VhostUserMsg *vmsg) 
    }

}



/* A test to see if we have userfault available */

static bool

have_userfault(void)

{

#if defined(__linux__) && defined(__NR_userfaultfd) &&\

        defined(UFFD_FEATURE_MISSING_SHMEM) &&\

        defined(UFFD_FEATURE_MISSING_HUGETLBFS)

    /* Now test the kernel we're running on really has the features */

    int ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);

    struct uffdio_api api_struct;

    if (ufd < 0) {

        return false;

    }



    api_struct.api = UFFD_API;

    api_struct.features = UFFD_FEATURE_MISSING_SHMEM |

                          UFFD_FEATURE_MISSING_HUGETLBFS;

    if (ioctl(ufd, UFFDIO_API, &api_struct)) {

        close(ufd);

        return false;

    }

    close(ufd);

    return true;



#else

    return false;

#endif

}



static bool

vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)

{
@@ -939,6 +968,10 @@ vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg) 
    uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |

                        1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ;



    if (have_userfault()) {

        features |= 1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT;

    }



    if (dev->iface->get_protocol_features) {

        features |= dev->iface->get_protocol_features(dev);

    }