A warning is triggered in amd_iommu_release_device() on removal of a device with an IOMMU_RESV_DIRECT region. The warning is based on the false assumption that correct attachment to the release_domain will always result in a NULL dev_data->domain pointer. For devices with IOMMU_RESV_DIRECT (and consequently dev->iommu->require_direct), the release domain is the permanent identity_domain which sets itself to dev_data->domain on attach. This behaviour was added in commit e94160488e65 ("iommu: Generic support for RMRs during device release"). Commit c21b34762e2f ("iommu/amd: Set release_domain to blocked_domain") caused it to take effect for AMD IOMMU. Remove the warning as it is no longer strictly an error to have a non-NULL domain pointer. As this leaves amd_iommu_release_device() empty, remove it. The warning was observed for a device with direct mapped region: /sys/bus/pci/devices/0000:04:00.0/iommu_group/reserved_regions: 0x00000000fee00000 0x00000000feefffff msi 0x000000fd00000000 0x000000ffffffffff reserved 0x0000fffd00000000 0x0000ffffffffffff direct Upon hotunplug: [ 28.715475] pcieport 0000:00:03.1: pciehp: Slot(0-3): Link Down [ 28.715482] pcieport 0000:00:03.1: pciehp: Slot(0-3): Card not present [ 28.715601] ------------[ cut here ]------------ [ 28.715603] WARNING: drivers/iommu/amd/iommu.c:2521 at amd_iommu_release_device+0x5d/0x70, CPU#4: irq/29-pciehp/99 [ 28.715657] RIP: 0010:amd_iommu_release_device+0x5d/0x70 [ 28.715687] Call Trace: [ 28.715689] [ 28.715694] iommu_deinit_device+0x84/0x110 [ 28.715699] __iommu_group_remove_device+0xa8/0xd0 [ 28.715703] iommu_bus_notifier+0x48/0x70 [ 28.715707] notifier_call_chain+0x48/0xe0 [ 28.715712] blocking_notifier_call_chain+0x45/0x60 [ 28.715716] bus_notify+0x3b/0x60 [ 28.715720] device_del+0x259/0x3b0 [ 28.715730] pci_remove_bus_device+0x85/0x100 [ 28.715735] pciehp_unconfigure_device+0x9d/0x180 [ 28.715743] __pciehp_disable_slot+0x47/0xe0 [ 28.715747] pciehp_handle_presence_or_link_change+0x80/0x5e0 [ 28.715753] pciehp_ist+0x162/0x290 Fixes: c21b34762e2f ("iommu/amd: Set release_domain to blocked_domain") Cc: stable@vger.kernel.org Signed-off-by: Kevin Mitchell --- Changes in v2: - Remove the warning alltogether as well as the now-empty amd_iommu_release_device() - Link to v1: https://lore.kernel.org/r/20261008202530.14501-2-kevmitch@arista.com drivers/iommu/amd/iommu.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 56262f6b1f70..d07abc342247 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -489,6 +489,10 @@ static void setup_aliases(struct amd_iommu *iommu, struct device *dev) clone_aliases(iommu, dev); } +/* + * We keep dev_data around for unplugged devices and reuse it when the + * device is re-plugged - not doing so would introduce a ton of races. + */ static struct iommu_dev_data *find_dev_data(struct amd_iommu *iommu, u16 devid) { struct iommu_dev_data *dev_data; @@ -2548,18 +2552,6 @@ static struct iommu_device *amd_iommu_probe_device(struct device *dev) return iommu_dev; } -static void amd_iommu_release_device(struct device *dev) -{ - struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev); - - WARN_ON(dev_data->domain); - - /* - * We keep dev_data around for unplugged devices and reuse it when the - * device is re-plugged - not doing so would introduce a ton of races. - */ -} - static struct iommu_group *amd_iommu_device_group(struct device *dev) { if (dev_is_pci(dev)) @@ -3205,7 +3197,6 @@ const struct iommu_ops amd_iommu_ops = { .domain_alloc_paging_flags = amd_iommu_domain_alloc_paging_flags, .domain_alloc_sva = amd_iommu_domain_alloc_sva, .probe_device = amd_iommu_probe_device, - .release_device = amd_iommu_release_device, .device_group = amd_iommu_device_group, .get_resv_regions = amd_iommu_get_resv_regions, .is_attach_deferred = amd_iommu_is_attach_deferred, -- 2.51.0