From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53291) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1evR9L-000095-US for qemu-devel@nongnu.org; Mon, 12 Mar 2018 13:22:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1evR9K-0007vR-95 for qemu-devel@nongnu.org; Mon, 12 Mar 2018 13:22:15 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:47236 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 1evR9K-0007v5-4C for qemu-devel@nongnu.org; Mon, 12 Mar 2018 13:22:14 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B9C98406E97D for ; Mon, 12 Mar 2018 17:22:13 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" Date: Mon, 12 Mar 2018 17:21:23 +0000 Message-Id: <20180312172124.56461-29-dgilbert@redhat.com> In-Reply-To: <20180312172124.56461-1-dgilbert@redhat.com> References: <20180312172124.56461-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v5 28/29] libvhost-user: Claim support for postcopy List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, mst@redhat.com, maxime.coquelin@redhat.com, marcandre.lureau@redhat.com, peterx@redhat.com, quintela@redhat.com Cc: aarcange@redhat.com 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 --- 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 504ff5ea59..beeed0c43f 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 2.14.3