From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51348) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ey7mo-00076Z-MM for qemu-devel@nongnu.org; Mon, 19 Mar 2018 23:18:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ey7mk-0008Qe-1O for qemu-devel@nongnu.org; Mon, 19 Mar 2018 23:18:06 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34308 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ey7mj-0008QV-SZ for qemu-devel@nongnu.org; Mon, 19 Mar 2018 23:18:01 -0400 Date: Tue, 20 Mar 2018 05:18:01 +0200 From: "Michael S. Tsirkin" Message-ID: <1521515720-612046-50-git-send-email-mst@redhat.com> References: <1521515720-612046-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1521515720-612046-1-git-send-email-mst@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL v2 49/50] libvhost-user: Claim support for postcopy List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , "Dr. David Alan Gilbert" , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Maxime Coquelin , Peter Xu From: "Dr. David Alan Gilbert" Tell QEMU we understand the protocol features needed for postcopy. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Marc-Andr=C3=A9 Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- contrib/libvhost-user/libvhost-user.c | 33 +++++++++++++++++++++++++++++= ++++ 1 file changed, 33 insertions(+) diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-use= r/libvhost-user.c index 504ff5e..beeed0c 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -185,6 +185,35 @@ vmsg_close_fds(VhostUserMsg *vmsg) } } =20 +/* 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 =3D syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); + struct uffdio_api api_struct; + if (ufd < 0) { + return false; + } + + api_struct.api =3D UFFD_API; + api_struct.features =3D 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, VhostUserM= sg *vmsg) uint64_t features =3D 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD | 1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ; =20 + if (have_userfault()) { + features |=3D 1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT; + } + if (dev->iface->get_protocol_features) { features |=3D dev->iface->get_protocol_features(dev); } --=20 MST