iommu/vt-d: Fix clearing real DMA device's scalable-mode context entries

mainline inclusion
from mainline-5.14-rc2
commit 474dd1c6
category: bugfix
bugzilla: 174363 https://gitee.com/openeuler/kernel/issues/I4DDEL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=474dd1c6506411752a9b2f2233eec11f1733a099

------------------------------------------------

The commit 2b0140c6 ("iommu/vt-d: Use pci_real_dma_dev() for mapping")
fixes an issue of "sub-device is removed where the context entry is cleared
for all aliases". But this commit didn't consider the PASID entry and PASID
table in VT-d scalable mode. This fix increases the coverage of scalable
mode.
Suggested-by: NSanjay Kumar <sanjay.k.kumar@intel.com>
Fixes: 8038bdb8 ("iommu/vt-d: Only clear real DMA device's context entries")
Fixes: 2b0140c6 ("iommu/vt-d: Use pci_real_dma_dev() for mapping")
Cc: stable@vger.kernel.org # v5.6+
Cc: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210712071712.3416949-1-baolu.lu@linux.intel.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NJing Xiangfeng <jingxiangfeng@huawei.com>
Reviewed-by: NChen Wandun <chenwandun@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/iommu/intel/iommu.c

@@ -5198,14 +5198,13 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 	iommu = info->iommu;
 	domain = info->domain;
 
-	if (info->dev) {
+	if (info->dev && !dev_is_real_dma_subdevice(info->dev)) {
 		if (dev_is_pci(info->dev) && sm_supported(iommu))
 			intel_pasid_tear_down_entry(iommu, info->dev,
 					PASID_RID2PASID, false);
 
 		iommu_disable_dev_iotlb(info);
-		if (!dev_is_real_dma_subdevice(info->dev))
-			domain_context_clear(info);
+		domain_context_clear(info);
 		intel_pasid_free_table(info->dev);
 	}