Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934106AbcDLV1Z (ORCPT ); Tue, 12 Apr 2016 17:27:25 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:50842 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966491AbcDLUxz (ORCPT ); Tue, 12 Apr 2016 16:53:55 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Michael S . Tsirkin" , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 45/70] virtio: virtio 1.0 cs04 spec compliance for reset Date: Tue, 12 Apr 2016 13:52:30 -0700 Message-Id: <1460494375-30070-46-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1460494375-30070-1-git-send-email-kamal@canonical.com> References: <1460494375-30070-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1748 Lines: 50 4.2.8-ckt8 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: "Michael S. Tsirkin" commit 05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c upstream. The spec says: after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Kamal Mostafa --- drivers/virtio/virtio_pci_modern.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index 8e5cf19..4469202 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -17,6 +17,7 @@ * */ +#include #define VIRTIO_PCI_NO_LEGACY #include "virtio_pci_common.h" @@ -271,9 +272,13 @@ static void vp_reset(struct virtio_device *vdev) struct virtio_pci_device *vp_dev = to_vp_device(vdev); /* 0 status means a reset. */ vp_iowrite8(0, &vp_dev->common->device_status); - /* Flush out the status write, and flush in device writes, - * including MSI-X interrupts, if any. */ - vp_ioread8(&vp_dev->common->device_status); + /* After writing 0 to device_status, the driver MUST wait for a read of + * device_status to return 0 before reinitializing the device. + * This will flush out the status write, and flush in device writes, + * including MSI-X interrupts, if any. + */ + while (vp_ioread8(&vp_dev->common->device_status)) + msleep(1); /* Flush pending VQ/configuration callbacks. */ vp_synchronize_vectors(vdev); } -- 2.7.4