[Patch v4 7/9] iommu/amd: copy old trans table from old kernel

[Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

From: Baoquan HE <bhe-sa4SJRhfYT7yzlqKoElxGh/sF2h8X+2i0E9HWUfgJXw@public.gmane.org>

Here several things need be done:
1) Initialize amd_iommu_dev_table because it was set several times
   since kdump kernel reboot. We don't need the set because we will
   copy the content from old kernel.
2) Re-enable event/cmd buffer
3) Install the DTE table to reg
4) Flush all caches

Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/iommu/amd_iommu_init.c | 47 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 71c7ac9..66a1fa5 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -35,7 +35,7 @@
 #include <asm/iommu_table.h>
 #include <asm/io_apic.h>
 #include <asm/irq_remapping.h>
-
+#include <linux/crash_dump.h>
 #include "amd_iommu_proto.h"
 #include "amd_iommu_types.h"
 #include "irq_remapping.h"
@@ -675,7 +675,7 @@ static int copy_dev_tables(void)
 	static int copied;
 
         for_each_iommu(iommu) {
-		if (!translation_pre_enabled()) {
+		if (!translation_pre_enabled(iommu)) {
 			pr_err("IOMMU:%d is not pre-enabled!/n", iommu->index);
 			return -1;
 		}
@@ -1160,8 +1160,13 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 	iommu->int_enabled = false;
 
 	init_translation_status(iommu);
+	if (translation_pre_enabled(iommu) && !is_kdump_kernel()) {
+                        clear_translation_pre_enabled(iommu);
+                        pr_warn("Translation was enabled for IOMMU:%d but we are not in kdump mode\n",
+                                iommu->index);
+                }
 
-	if (translation_pre_enabled())
+	if (translation_pre_enabled(iommu))
 		pr_warn("Translation is already enabled - trying to copy translation structures\n");
 
 	ret = init_iommu_from_acpi(iommu, h);
@@ -1730,9 +1735,41 @@ static void early_enable_iommu(struct amd_iommu *iommu)
 static void early_enable_iommus(void)
 {
 	struct amd_iommu *iommu;
+	bool is_pre_enabled=false;
 
-	for_each_iommu(iommu)
-		early_enable_iommu(iommu);
+	for_each_iommu(iommu) {
+		if ( translation_pre_enabled(iommu) ) {
+			is_pre_enabled = true;
+			break;
+		}
+	}
+
+	if ( !is_pre_enabled) {
+		for_each_iommu(iommu)
+			early_enable_iommu(iommu);
+	} else {
+		if (copy_dev_tables()) {
+			pr_err("Failed to copy translation tables from previous kernel.\n");
+			/*
+			 * If failed to copy dev tables from old kernel, continue to proceed
+			 * as it does in normal kernel.
+			 */
+			for_each_iommu(iommu) {
+				clear_translation_pre_enabled(iommu);
+				early_enable_iommu(iommu);
+			}
+		} else {
+			pr_info("Copied translation tables from previous kernel.\n");
+			for_each_iommu(iommu) {
+				iommu_feature_disable(iommu, CONTROL_CMDBUF_EN);
+		                iommu_feature_disable(iommu, CONTROL_EVT_LOG_EN);
+		                iommu_enable_command_buffer(iommu);
+		                iommu_enable_event_buffer(iommu);
+		                iommu_set_device_table(iommu);
+		                iommu_flush_all_caches(iommu);
+			}
+		}
+	}
 }
 
 static void enable_iommus_v2(void)
-- 
2.5.5