From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752813AbeDKJQz (ORCPT ); Wed, 11 Apr 2018 05:16:55 -0400 Received: from baptiste.telenet-ops.be ([195.130.132.51]:39598 "EHLO baptiste.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291AbeDKJPy (ORCPT ); Wed, 11 Apr 2018 05:15:54 -0400 From: Geert Uytterhoeven To: Baptiste Reynal , Alex Williamson Cc: Philipp Zabel , Rob Herring , Mark Rutland , kvm@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH] vfio: platform: Fix using devices in PM Domains Date: Wed, 11 Apr 2018 11:15:46 +0200 Message-Id: <1523438149-16433-1-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a device is part of a PM Domain (e.g. power and/or clock domain), its power state is managed using Runtime PM. Without Runtime PM, the device may not be powered up, causing subtle failures, crashes, or system lock-ups when the device is accessed by the guest. Fix this by adding Runtime PM support, powering the device when the VFIO device is opened by the guest. Note that while more fine-grained power management could be implemented on the guest side, if exported, this would be inherently unsafe, as abusing it may kill the whole system. Signed-off-by: Geert Uytterhoeven --- drivers/vfio/platform/vfio_platform_common.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index 3c13327b2777f8ec..9d46fce2446daebe 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -255,6 +256,8 @@ static void vfio_platform_release(void *device_data) const char *extra_dbg = NULL; int ret; + pm_runtime_put(vdev->device); + ret = vfio_platform_call_reset(vdev, &extra_dbg); if (ret && vdev->reset_required) { dev_warn(vdev->device, "reset driver is required and reset call failed in release (%d) %s\n", @@ -297,6 +300,10 @@ static int vfio_platform_open(void *device_data) ret, extra_dbg ? extra_dbg : ""); goto err_rst; } + + ret = pm_runtime_get_sync(vdev->device); + if (ret < 0) + goto err_rst; } vdev->refcnt++; @@ -712,6 +719,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, mutex_init(&vdev->igate); + pm_runtime_enable(vdev->device); return 0; put_iommu: @@ -729,6 +737,7 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev) vdev = vfio_del_group_dev(dev); if (vdev) { + pm_runtime_disable(vdev->device); vfio_platform_put_reset(vdev); vfio_iommu_group_put(dev->iommu_group, dev); } -- 2.7.4