From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752727AbbCEWJy (ORCPT ); Thu, 5 Mar 2015 17:09:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:5917 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751378AbbCEWJw (ORCPT ); Thu, 5 Mar 2015 17:09:52 -0500 Date: Thu, 5 Mar 2015 23:09:43 +0100 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Rusty Russell , virtualization@lists.linux-foundation.org, Pawel Moll Subject: [PATCH] virtio_mmio: generation support Message-ID: <1425593244-18869-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-Fcc: =sent Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org virtio_mmio currently lacks generation support which makes multi-byte field access racy. Fix by getting the value at offset 0xfc for version 2 devices. Nothing we can do for version 1, so return generation id 0. Signed-off-by: Michael S. Tsirkin --- Pawel, you mentioned you have a working virtio 1.0 hypervisor, can you pls confirm this works correctly? drivers/virtio/virtio_mmio.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 0375456..69b2e4d 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -237,6 +237,16 @@ static void vm_set(struct virtio_device *vdev, unsigned offset, } } +static u32 vm_generation(struct virtio_device *vdev) +{ + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); + + if (vm_dev->version == 1) + return 0; + else + return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION); +} + static u8 vm_get_status(struct virtio_device *vdev) { struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); @@ -503,6 +513,8 @@ static const char *vm_bus_name(struct virtio_device *vdev) static const struct virtio_config_ops virtio_mmio_config_ops = { .get = vm_get, .set = vm_set, + .generation = vm_generation, + .get_status = vm_get_status, .get_status = vm_get_status, .set_status = vm_set_status, .reset = vm_reset, -- MST