From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:53945) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gtYoF-0007ZV-P4 for qemu-devel@nongnu.org; Tue, 12 Feb 2019 09:13:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gtYoE-0005t9-Ee for qemu-devel@nongnu.org; Tue, 12 Feb 2019 09:13:15 -0500 From: Stefan Hajnoczi Date: Tue, 12 Feb 2019 22:12:31 +0800 Message-Id: <20190212141234.2814-4-stefanha@redhat.com> In-Reply-To: <20190212141234.2814-1-stefanha@redhat.com> References: <20190212141234.2814-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [RFC PULL 3/6] virtio-blk: add "discard" and "write-zeroes" properties List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , qemu-devel@nongnu.org Cc: sgarzare@redhat.com, qemu-block@nongnu.org, "Dr . David Alan Gilbert" , "Michael S . Tsirkin" , Stefan Hajnoczi , Pankaj Gupta From: Stefano Garzarella In order to avoid migration issues, we enable DISCARD and WRITE_ZEROES features only for machine type >=3D 4.0 As discussed with Michael S. Tsirkin and Stefan Hajnoczi on the list [1], DISCARD operation should not have security implications (eg. page cache attacks), so we can enable it by default. [1] https://lists.gnu.org/archive/html/qemu-devel/2019-02/msg00504.html Suggested-by: Dr. David Alan Gilbert Reviewed-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi Signed-off-by: Stefano Garzarella Acked-by: Pankaj Gupta Message-id: 20190208134950.187665-4-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/block/virtio-blk.c | 4 ++++ hw/core/machine.c | 2 ++ 2 files changed, 6 insertions(+) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 938273c63c..6f2e86264d 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1026,6 +1026,10 @@ static Property virtio_blk_properties[] =3D { DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128), DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHRE= AD, IOThread *), + DEFINE_PROP_BIT64("discard", VirtIOBlock, host_features, + VIRTIO_BLK_F_DISCARD, true), + DEFINE_PROP_BIT64("write-zeroes", VirtIOBlock, host_features, + VIRTIO_BLK_F_WRITE_ZEROES, true), DEFINE_PROP_END_OF_LIST(), }; =20 diff --git a/hw/core/machine.c b/hw/core/machine.c index 077fbd182a..766ca5899d 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -33,6 +33,8 @@ GlobalProperty hw_compat_3_1[] =3D { { "usb-kbd", "serial", "42" }, { "usb-mouse", "serial", "42" }, { "usb-kbd", "serial", "42" }, + { "virtio-blk-device", "discard", "false" }, + { "virtio-blk-device", "write-zeroes", "false" }, }; const size_t hw_compat_3_1_len =3D G_N_ELEMENTS(hw_compat_3_1); =20 --=20 2.20.1