amd_iommu: remap the device table of IOMMU with the memory encryption mask for kdump

Orabug: 28796835

In kdump kernel, it will copy the device table of IOMMU from the old device
table, which is encrypted when SME is enabled in the first kernel. So we
have to remap the old device table with the memory encryption mask.

Signed-off-by: Lianbo Jiang <[email protected]>
Acked-by: Joerg Roedel <[email protected]>
Signed-off-by: Dan Duval <[email protected]>
Reviewed-by: Henry Willard <[email protected]>

Author: lian-bo

drivers/iommu/amd_iommu_init.c

@@ -902,12 +902,22 @@ static bool copy_device_table(void)
 		}
 	}
 
-	old_devtb_phys = entry & PAGE_MASK;
+	/*
+	 * When SME is enabled in the first kernel, the entry includes the
+	 * memory encryption mask(sme_me_mask), we must remove the memory
+	 * encryption mask to obtain the true physical address in kdump kernel.
+	 */
+	old_devtb_phys = __sme_clr(entry) & PAGE_MASK;
+
 	if (old_devtb_phys >= 0x100000000ULL) {
 		pr_err("The address of old device table is above 4G, not trustworthy!\n");
 		return false;
 	}
-	old_devtb = memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB);
+	old_devtb = (sme_active() && is_kdump_kernel())
+		    ? (__force void *)ioremap_encrypted(old_devtb_phys,
+							dev_table_size)
+		    : memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB);
+
 	if (!old_devtb)
 		return false;