From a11bfde9c77df1fd350ea27169ab921f511bf5d0 Mon Sep 17 00:00:00 2001 From: Joerg Roedel <jroedel@suse.de> Date: Mon, 17 Feb 2020 17:20:59 +0100 Subject: iommu/vt-d: Do deferred attachment in iommu_need_mapping() From: Joerg Roedel <jroedel@suse.de> commit a11bfde9c77df1fd350ea27169ab921f511bf5d0 upstream. The attachment of deferred devices needs to happen before the check whether the device is identity mapped or not. Otherwise the check will return wrong results, cause warnings boot failures in kdump kernels, like WARNING: CPU: 0 PID: 318 at ../drivers/iommu/intel-iommu.c:592 domain_get_iommu+0x61/0x70 [...] Call Trace: __intel_map_single+0x55/0x190 intel_alloc_coherent+0xac/0x110 dmam_alloc_attrs+0x50/0xa0 ahci_port_start+0xfb/0x1f0 [libahci] ata_host_start.part.39+0x104/0x1e0 [libata] With the earlier check the kdump boot succeeds and a crashdump is written. Fixes: 1ee0186b9a12 ("iommu/vt-d: Refactor find_domain() helper") Cc: stable@vger.kernel.org # v5.5 Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com> Acked-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/iommu/intel-iommu.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2452,9 +2452,6 @@ static void do_deferred_attach(struct de static struct dmar_domain *deferred_attach_domain(struct device *dev) { - if (unlikely(attach_deferred(dev))) - do_deferred_attach(dev); - return find_domain(dev); } @@ -3478,6 +3475,9 @@ static bool iommu_need_mapping(struct de if (iommu_dummy(dev)) return false; + if (unlikely(attach_deferred(dev))) + do_deferred_attach(dev); + ret = identity_mapping(dev); if (ret) { u64 dma_mask = *dev->dma_mask; @@ -3841,7 +3841,11 @@ bounce_map_single(struct device *dev, ph int prot = 0; int ret; + if (unlikely(attach_deferred(dev))) + do_deferred_attach(dev); + domain = deferred_attach_domain(dev); + if (WARN_ON(dir == DMA_NONE || !domain)) return DMA_MAPPING_ERROR;