From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1biIpY-0004lp-Gc for qemu-devel@nongnu.org; Fri, 09 Sep 2016 06:14:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1biIpT-0000LB-FZ for qemu-devel@nongnu.org; Fri, 09 Sep 2016 06:14:43 -0400 From: Maxime Coquelin Date: Fri, 9 Sep 2016 12:14:31 +0200 Message-Id: <1473416072-7063-2-git-send-email-maxime.coquelin@redhat.com> In-Reply-To: <1473416072-7063-1-git-send-email-maxime.coquelin@redhat.com> References: <1473416072-7063-1-git-send-email-maxime.coquelin@redhat.com> Subject: [Qemu-devel] [PATCH 1/2] virtio: Add backend feature testing functionnality List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: mst@redhat.com, qemu-devel@nongnu.org Cc: marcel@redhat.com, vkaplans@redhat.com, qemu-stable@nongnu.org, Maxime Coquelin This patch adds virtio_test_backend_feature() function to enable checking a backend feature before the negociation takes place. It may be used, for example, to check whether the backend supports VIRTIO_F_VERSION_1 before enabling modern capabilities. Cc: Marcel Apfelbaum Cc: Michael S. Tsirkin Cc: qemu-stable@nongnu.org Signed-off-by: Maxime Coquelin --- hw/virtio/virtio.c | 14 ++++++++++++++ include/hw/virtio/virtio.h | 2 ++ 2 files changed, 16 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 74c085c..7ab91a1 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1481,6 +1481,20 @@ void virtio_vmstate_save(QEMUFile *f, void *opaque, size_t size) virtio_save(VIRTIO_DEVICE(opaque), f); } +bool virtio_test_backend_feature(VirtIODevice *vdev, + unsigned int fbit, Error **errp) +{ + VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); + uint64_t feature; + + virtio_add_feature(&feature, fbit); + + assert(k->get_features != NULL); + feature = k->get_features(vdev, feature, errp); + + return virtio_has_feature(feature, fbit); +} + static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val) { VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index d2490c1..5fb74c8 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -235,6 +235,8 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val); void virtio_reset(void *opaque); void virtio_update_irq(VirtIODevice *vdev); int virtio_set_features(VirtIODevice *vdev, uint64_t val); +bool virtio_test_backend_feature(VirtIODevice *vdev, + unsigned int fbit, Error **errp); /* Base devices. */ typedef struct VirtIOBlkConf VirtIOBlkConf; -- 2.7.4