From 7139a2e929b9e3ca8d5c217cb8aec560be1faf00 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 1 Apr 2015 14:58:45 +0200 Subject: [PATCH] iommu/amd: Ignore BUS_NOTIFY_UNBOUND_DRIVER event Detaching a device from its domain at this event is problematic for several reasons: * The device might me in an alias group and detaching it will also detach all other devices in the group. This removes valid DMA mappings from the other devices causing io-page-faults and lets these devices fail. * Devices might have unity mappings specified by the IVRS table. These mappings are required for the device even when no device driver is attached. Detaching the device from its domain in driver unbind will also remove these unity mappings. This patch removes the handling of the BUS_NOTIFY_UNBOUND_DRIVER event to prevent these issues and align it better with the behavior of the VT-d driver. Tested-by: Suravee Suthikulpanit Signed-off-by: Joerg Roedel --- drivers/iommu/amd_iommu.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 8a1dea4d0d26..994cc7dbb833 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -2422,16 +2422,6 @@ static int device_change_notifier(struct notifier_block *nb, dev_data = get_dev_data(dev); switch (action) { - case BUS_NOTIFY_UNBOUND_DRIVER: - - domain = domain_for_device(dev); - - if (!domain) - goto out; - if (dev_data->passthrough) - break; - detach_device(dev); - break; case BUS_NOTIFY_ADD_DEVICE: iommu_init_device(dev); -- 2.20.1