From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52965) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dkxpG-0003ix-Od for qemu-devel@nongnu.org; Thu, 24 Aug 2017 15:29:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dkxpF-0005f5-QE for qemu-devel@nongnu.org; Thu, 24 Aug 2017 15:29:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35702) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dkxpF-0005es-Ju for qemu-devel@nongnu.org; Thu, 24 Aug 2017 15:29:57 -0400 From: "Dr. David Alan Gilbert (git)" Date: Thu, 24 Aug 2017 20:27:27 +0100 Message-Id: <20170824192730.8440-30-dgilbert@redhat.com> In-Reply-To: <20170824192730.8440-1-dgilbert@redhat.com> References: <20170824192730.8440-1-dgilbert@redhat.com> Subject: [Qemu-devel] [RFC v2 29/32] vhost-user: Claim support for postcopy List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, maxime.coquelin@redhat.com, a.perevalov@samsung.com, mst@redhat.com, marcandre.lureau@redhat.com Cc: quintela@redhat.com, peterx@redhat.com, lvivier@redhat.com, aarcange@redhat.com, felipe@nutanix.com From: "Dr. David Alan Gilbert" Tell QEMU we understand the protocol features needed for postcopy. Signed-off-by: Dr. David Alan Gilbert --- contrib/libvhost-user/libvhost-user.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c index 23bff47649..290748733b 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -144,6 +144,35 @@ 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) { @@ -796,6 +825,10 @@ vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg) { uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD; + if (have_userfault()) { + features |= 1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT; + } + if (dev->iface->get_protocol_features) { features |= dev->iface->get_protocol_features(dev); } -- 2.13.5